BIOLOGY PP2 EXAMINERS' PROJECTION 70 PAPERS.(new ...

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BIOLOGY PP2 EXAMINERS’

PROJECTION 70 PAPERS.(new version)

N/B In Response to the Huge Costs Associated in Coming Up with

Such/Similar Resources Regulary, We inform us All, MARKING

SCHEMES ARE NOT FREE OF CHARGE. However Similar

QUESTIONS, Inform of soft Copies are Absolutely FREE to

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by Amobi Soft Copy Publishers

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PROJECTION NO. 01

Name………………………………………………………. Index No…………………/…….

School……………………………………………………… Candidates Signature………………

Date ………………………………..

NSTRUCTIONS TO CANDIDATES

• Write your name and Index Number in the spaces provided above.

• Sign and write date of examination in the spaces provided above.

• This paper consists of two sections. Section A and section B.

• Answer ALL questions in section A in the spaces provided. In section B answer question 6 (compulsory) and either question 7 or 8 in the spaces provided after question 8

For Examiners use only.

Section Question Maximum Score Candidates Score

A

1 8

2 8

3 8

4 8

5 8

B

6 20

7 20

8 20

TOTAL SCORE 80

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SECTION A: (40 MARKS)

Answer all the questions in this section in the spaces provided

1. The diagram below represents a mature bread mould (Rhizopus)

(a) Name the structures P, Q and R (3mks)

P:……………………………………………………………….

Q:………………………………………………………………

R:……………………………………………………………….

(b) What is the function of the structure P? (1mk)

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(c) State two economic importances of moulds (2mks)

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(d) (i) Name the kingdom to which bread mould belong (1mk)

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(ii) List down one general characteristic of member of the kingdom named in d (i)

above. (1mk)

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2. The diagram below represents a longitudinal section through a dicotyledonous root tip.

(a) State the function of the part labeled M (1mk)

K…………………………………………………………..

L……………………………………………………………

M…………………………………………………………..

(b) State the function of the part labeled N (1mk)

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(c) Name the process by which water moves from the soil particles into plant root (1mk)

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(d) How is the structure labeled L different from that of the stem of the plant. (1mk)

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(e) Name the zones labeled Y and Z (2mks)

Y………………………………………………………..

Z………………………………………………………..

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3. Pure breed of red cows and pure breed of white bulls were crossed to give F1 calves which had a

mixture of red and white coat known as roan. The F1 were selfed.

(a) Using letter R to represent gene for red colour and W to represent gene for white colour

work out the phenotypic ratio of F2. (4mks)

(b) Work out the genotypic ratio of a cross between F1 offspring and white bull. (3mks)

(c) Comment on the gene(s) controlling the colour of coats in cattle mentioned above. (1mk)

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4. The quantities of urine passed out per day was established in five animals P, Q, R, S and T of the

same species in their natural habitants. The results were as shown below.

(a) (i) Which of the five animals was likely to be excreting urine very rich in ammonia. (1mk)

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(ii) Give a reason for your answer in (a) (i) above (1mk)

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(b) (i) Which of the animals was likely to be living in a desert environment (1mk)

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(ii) Give a reason for your answer in (b) (i) above (1mk)

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(c) Explain how ingestion of very salty food may affect the quantity of urine produced. (2mks)

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Qu

anti

ty o

f u

rin

e

(dm

3 )

Animals

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5. The diagram below represents a section through the mammalian ear. Study it and answer the

questions that follow.

(a) Name the structures labeled H and J (2mks)

H………………………………………………………………………..……………………………….

J………………………………………………………………………………………………………….

(b) State how the structures labeled H, M and N are adapted to their functions (3mks)

H

……………………………………………………………………………………………………………………………………………………………

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M

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N

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(c) State what would happen if the structure labeled K was completely damaged (1mk)

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(d) Name the fluid contained in structure N (1mk)

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(e) Apart from hearing, state the other role performed by the human ear (1mk)

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SECTION B (40 MARKS)

Answer question 6 (compulsory) in the spaces provided and either question 7 or 8 in the spaces provided

after question 8.

6. The table below shows the population of a housefly Musca domistica which is parasitized by wasps

of species Nasonia Spp. The investigation of their population growth pattern was carried out for 70

weeks. In these experimental space and physical factors were assumed not to be limiting.

Time in

weeks

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70

Musca

domestica

40 70 110 260 350 480 400 395 350 40 60 140 250 240 230

Nasonia

spp

10 20 30 45 100 200 300 380 410 250 60 20 40 200 280

(a) Using the readings in the table, plot graphs on the same axis of population growth of

organisms against time. (8mks)

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(b) Account for the growth of

(i) Musca domestica between 10th week – 25th week (1mk)

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(ii) Nasonia species between 40th week – 50th week (1mk)

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(c) What is the population of?

(i) Nasonia Spp on the 62nd week (1mk)

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(ii) Musca domestica on the 4th week (1mk)

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(d) Bemex, another parasite of housefly was introduced into the ecosystem. Giving a reason

what will be the effect on the population of

(i) Housefly Musca domestica (2mks)

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(ii) Nasonia Spp (2mks)

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(e) In estimating the population of Musca domestica in the experiment above, capture-

recapture method was used. Describe the procedure which was followed. (4mks)

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7. Describe how fruits and seeds are suited to their mode of dispersal (20mks)

8. (a) What is natural selection? (2mks)

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(b) Describe how natural selection brings about adaptation of a species of a living organism to

its environment. (18mks)

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PROJECTION NO. 02

231/2

BIOLOGY

PAPER 2

THEORY

2 HOURS

SECTION A (40 MARKS)

1. In a family with four children, the father had blood group A while the mother had blood

group B. One of the children had blood group 0.

(a) (i) What were the genotypes of the parents? (1mk)

Mother

Father

(ii) What was the genotype of the child with blood group 0? (1mk)

(b) Work out the genotypes of the other children.

(c) Which child can receive blood from any member of the family? (1mk)

(d) State the percentage of children who can donate blood at all blood groups. (1mk)

2. (a) What is active transport? (1mk)

(b) State three factors that increase the rate of active transport. (3mks)

(c) Give four roles of active transport in living organisms. (4mks)

3. The diagram below represents one of the joints in the mammalian skeleton.

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(a) Name the type of joint shown in the diagram.

(b) Name the parts labeled Z and U.

Z: …………………………………………………………………………………

U: ……………………………………………………………………………………

(c) Name two parts of the body where this type of joint is found. (2mks)

(d) State the functions of the fluid found in W. (2mks)

(e) Name the type of muscles found in the gut. (1mk)

4. (a) What is accommodation? (1mk)

(b) Describe the sequence of events that occur in the eye for one to be able to see

clearly

(i) a distant object (4mks)

(ii) if one moved from a dim lit room to bright light. (3mks)

5. An experiment was set up to investigate a certain process as shown in the diagram below.

The set up was left in bright sunlight for 4 hours.

(a) State the aim of the experiment. (1mk)

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(b) Name X and Y. (2mks)

X: ……………………………………………………………………………………

Y: ………………………………………………………………………………………

(c) Other than sunlight, name three factors that would affect the experiment. (3mks)

(d) State how the identity of X could be confirmed. (1mk)

(e) Explain why only submerged water plants are used in this experiment. (1mk)

6. In an ecological study, a grass hopper population and that of crows was estimated in a

certain grassland area over a period of one year. The results are as shown in the table

below.

Month J F M A M J J A S 0 N D

Number of adult

grasshoppers xl02 90 20 11 25 2500 1652 120 15 10 35 192 456

Number of crows 4 2 0 1 8 22 7 2 1 1 5 15

Amount of rainfall 20 0 55 350 520 350 12 10 25 190 256 350

(i) What is the relationship between the rainfall and grasshopper population? (1mk)

(ii) (a) Account for the relationship stated in a (i) above. (3mks)

(b) Explain the relationship between the grasshopper population and that of the crows.

(3mks)

(c) If the data was used in the construction of pyramid of numbers, what would be the

trophic level of;

(3mks)

i. Grasshopper

ii. Crows

iii. The grass in the study area

(d) If the area studied was one square kilometer, state;

(i) One method that could have been used to estimate the crow population. (1mk)

(ii) One method that could have been used to estimate the grasshopper population. (1mk)

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(e) Suggest what would happen if a predator for grasshoppers entered the study area.

(2mks)

(f) What is meant by the term carrying capacity? (1mk)

(g) Why would the carrying capacity of wild animals in woodland grassland be higher

than that of cattle?

(2mks)

(h) What is an ecosystem? (3mks)

7. Describe the role of the liver in homeostasis. (20mks)

8. (a) State three reasons why transport is necessary in animals. (3mks)

(b) Describe how the mammalian heart is adapted to its function. (17mks)

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PROJECTION NO. 03

Name………………………………………………………. Index No…………………/…….

School……………………………………………………… Candidates Signature………………

INSTRUCTIONS TO CANDIDATES






A 1 - 5 40

B 6 20

7 20

8 20

TOTAL SCORE 80

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Answer all the questions in this section in the spaces provided

1. The diagram below illustrates the mechanism of gaseous exchange in mammalian lungs.

a) Name the tissues labeled M and N (2mks)

M:………………………………..…… N:…………….…….……………….

b) Name the gases labeled V and W (2mks)

V:………………………………..…… W:…………….…….……………….

c) Name the cell labeled Z (1mk)

Z:………………………………..……

V W

M

N Z

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d) State three adaptations of alveolus to its function. (3mks)

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2. John ate rice and beans for breakfast.

a) State the physical and chemical processes that occurred in the mouth cavity.

Physical ………………………………………………………………………… (1mk)

Chemical ……………………………………………………………………….. (1mk)

b) Name the digestive juices that will be released into (3mks)

i) The mouth cavity ………………………………………………………………………………..

ii) The stomach……………………………………………………………………………………..

iii) The duodenum………………………………………………………………………………….

c) Explain how the ileum is adapted to its functions (3mks)

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3. Form three students in Geteri secondary were estimating the number of tsetse flies in a

small bush near the school. At first they caught 400 tsetse flies, marked and released

them. After five days, they caught 500 tsetse flies of which 80 had been marked.

a) i) Calculate the tsetse flies population in the bush. (3mks)

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ii) State the method used in estimating the population of tsetse flies. (1mk)

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b) State two abiotic and two biotic factors that influence tsetse fly population in a

bush.

i) Abiotic factors (2mks)

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ii) biotic factors (2mks)

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4. a) The diagram below shows a defect in a human eye.

i) Name the defect. (1mk)

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ii) State what brings about the defect in (a)(i) above. (1mk)

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iii) State how the defect can be corrected (1mk)

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b) Explain the changes in the eye during vision in bright light. (3mks)

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c) State the functions of the mammalian ear. (2mks)

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Light rays

Blurred image

Lens

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5. In a certain variety of tomato, a recessive mutant gene which is responsible for

chlorophyll synthesis causes the leaves of the plant to be white when present in

homozygous condition. This kind of plant dies soon after germination. In the

heterozygous state, the mutant produces a plant with variegated leaves which normally

completes its life cycle.

i) Suggest why the homozygous recessive plant is only able to survive germination but

not to complete its life cycle thereafter. (3mks)

…………………………………………………………………………………………………………………………………………

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ii) Work out the phenotypic ratio of the offspring’s that would be produced as a result

of self pollination of the plants with variegated leaves. (5mks)

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SECTION B: (40MARKS)

Answer question 6 compulsory in the spaces provided and either question 7 or 8 in the spaces

provided after question 8.

6. An experiment was carried out whereby three healthy rats were fed on equal amounts

of glucose. After half an hour, the glucose concentration per ml. of blood was measured

at 15 minutes intervals for three hours. The following results were obtained.

0 min 15 min 30 min 45 min 60 min 75 min 90 min

A 0.800 0.774 0.715 0.680 0.650 0.595 0.555

B 0.745 0.695 0.695 0.660 0.635 0.600 0.545

C 0.795 0.695 0.665 0.635 0.590 0.550 0.495

Mean 0.780 0.720 0.691 - 0.625 - 0.532

a) i) Calculate the mean concentration of glucose in mg per ml of blood at 45 and 75

minutes.

Record your answer on the table. (2mks)

ii) On the graph paper provided, plot a graph of the mean glucose concentration

against time. (6mks)

Glucose

conc.

mg/ml

Rats

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iii) What was the mean glucose concentration in the blood after 37.5 minutes? (1mk)

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iv) Give a reason why it was necessary to use three rats in the experiment instead of one. (1mk)

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v) Why was the initial concentration of glucose in the rats not the same? (2mks)

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vi) Account for the difference in mean glucose concentration during the period. (3mks)

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b) Give two reasons why glucose is the main respiratory substrate. (2mks)

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c) Give three ways in which glucose is assimilated in the body. (3mks)

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7. Describe how the mammalian heart is structurally adapted to its functions. (20mks)

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8. Describe the events that take place from the time a pollen grain lands on the stigma of the flower

up to the time the seeds form. (20mks)

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PROJECTION NO. 04

NAME: ……………………………………. INDEX NUMBER: ……………………………….

SCHOOL: ………………………………… CANDIDATES SIGNATURE: …………………..

DATE: ……………………………………………..

231/2

BIOLOGY

THEORY

PAPER 2

2 Hours



• Answer ALL the questions in the spaces provided

FOR EXAMINER’S USE ONLY

SECTIONS QUESTION MAXIMUM SCORE CANDIDATE’S

SCORE

A

1 8

2 8

3 8

4 8

5 8

B

6 20

7 OR 8 20

TOTAL SCORE 80

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SECTION A 40 MARKS

Answer All questions in the spaces provided)

1. A group of students’ set-up an experiment to investigate a certain physiological process.

The set up was as shown in the figure below.

After sometime the student observed that a sugar solution was formed and its level rose

in the cavity where sugar crystals were placed.

a) What physiological process was being investigated? (1mk)

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b) Account for the formation of sugar solution and its rise in level. (3mks)

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c) Suggest the result the students would obtain if they repeated the experiment using

a boiled pawpaw. Give reasons (2mks)

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d) State two importance of the physiological process named in 1 a) above to plants (2mks)

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2. In an experiment some germinating seeds were placed in a large airtight flask and left for

Four days.

a) Suggest the expected changes in the composition of gases in the flask on the fifth

day. (2mks)

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b) Give reasons for your answer a) above. (1mk)

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c) Name two factors that cause dormancy in seeds. (2mks)

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………………………………………………………………………………………………………….…………………………………

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d) Account for the loss in dry weight of cotyledons in a germinating pea seed. (2mks)

……………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………….

………………………………………………………………………………………………………………………………………………

e) Name the hormone that causes moulting in insects. (1mk)

……………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………..

3. The diagram below shows part of the human digestive system.

a) Identify the parts labeled A, C, G and H (2mks)

A ……………………………………………..… C …………………………………………………..………..

G ………………………………………………… H ……………………………………………………..……..

b) Name one substance absorbed at part labeled E ………………………………………..…….. (1mk)

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c) State one role of the substance stored in structure labeled I in digestion. (1mk)

…………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………..

d) Explain three ways by which structure labeled D is adapted for absorption of the

products of digestion (3mks)

……………………………………………………………………………………….……………………………………………..……

……………………………………………………………………………………………………………………..……………………

……………………………………………………………………………………………………………………………….…………

……………………………………………………………………………………………………………………………….…………

e) State role of hydrochloric acid secreted by the walls of structure labeled B. (1mk)

………………………………………………………………………………………………………………..………………………

…………………………………………………………………………………………………………………………………………

4. In a family with two children, the mother had blood group A while the father had blood

group B. One of their children had blood group AB.

a) i) What are the genotypes of the parents? (2mks)

Mother…………………………………. Father ………………………………

ii) What was the genotype of the child with blood group AB? (1mk)

…………………………………………………………………………………………………………………………….……………

…………………………………………………………………………………………………………………………………………

b) Determine the possible genotypes of the other children (4mks)

……………………………………………………………………………………………….…………………………………………………..………

…………………………………………………………………………………………..………………………………………………………….……

………………………………………………………………………………………………………………………………………………….…………

……………………………………………………………………………………………………………………………………………………….……

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…………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………………………

c) What is the advantage of having blood group AB? (1mk)

……………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………………

5. In an investigation to compare the basal metabolic rate of some animals, the amount of

Oxygen absorbed per unit body weight in a given time was determined. The results are as

indicated in the table below.

Animal Body weight (kg) Volume of oxygen absorbed

(gm/hr)

Buffalo

Baboon

Dog

Rat

Mouse

4,500

70

12

0.1

0.025

53

190

280

870

1,580

a) What is the meaning of the term basal metabolic rate? (1mk)

…………………………………………………………………………………………………………………..…………………………

…………………………………………………………………………………………………………………..…………………………

b) i) Compare the volume of oxygen consumed between the buffalo and the

mouse (2mks)

………………………………………………………………………………………………………………………….……..……………

………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………….……

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ii) Account for the comparison in b i) above

buffalo (2mks)

………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………..……

……………………………………………………………………………………………………………………………………………..

…………………………………………………………………………………………………………………………………………….

Mouse (2mks)

………………………………………………………………………………………..……………………………………………………

………………………………………………………………………………………………………………………………..……………

………………………………………………………………………………………………………………………….…………………

……………………………………………………………………………………………………………………………………………

c) State one other factors that affects basal metabolic rate of an organism. (1mk)

……………………………………………………………………………………………………………………………………….…

………………………………………………………………………………………………………………………………………….

SECTION B. (40 MARKS)

Answer question 6 (compulsory) and either question 7 or 8 in the spaces provided after question 8.

6. Ten young rats were placed in a cage. The amount of food available to the mice each day was

kept constant. The results obtained were as shown in the table below

Time in months 0 2 4 6 8 10 12 14 16 18

Number of rats 10 10 55 105 300 445 440 180 135 150

a) Using a suitable scale, plot a graph of a number of rats against time (6mks)

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b) With reference to the graph, account for the changes in rat population between

i) 0 to 2 months (1mk)

…………………………………………………………………………………………………….………………………………….……

………………………………………………………………………………………………………………………………………………

ii) 2 to 10 months (2mks)

………………………………………………………………………………………………………………………..……………………

……………………………………………………………………………………………………………………………..………………

……………………………………………………………………………………………………………………………..………………

………………………………………………………………………………………………………………………………………………

iii) 10 to 12 months (2mks)

…………………………………………………………………………………………………………………………………..…………

………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………….……………

………………………………………………………………………………………………………………………………….……………

iv) 12 to 16 months (2mks)

………………………………………………………………………………………………………………………………….…………

…………………………………………………………………………………………………………………………….………………

………………………………………………………………………………………………………………………………….…………

………………………………………………………………………………………………………………………………….…………

c) i) Between which two months was the population change greatest. (1mk)

………………………………………………………………………………………………………………..……………………………

……………………………………………………………………………………………………………………………………..………

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ii) Calculate the rate of population change over the period you have given

in a) above (2mks)

d) Briefly describe how you would use the capture – recapture method to estimate the

population of grasshoppers. (4mks)

…………………………………………………………………………………………………………………………….…………………

…………………………………………………………………………………………………………………………….…………………

………………………………………………………………………………………………………………………….……………………

…………………………………………………………………………………………………………………………………………….…

………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………….

7. Discuss the adaptations of the mammalian skin to its function. (20mks)

8. a) Explain the meaning of each of the following as used in evolution.

i) Natural selection (3mks)

………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………..…………………………………

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ii) Struggle for existence (3mks)

………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………..…………………………………

…………………………………………………………………………………………………………………………………………….

b) Discuss the evidences of organic evolution (14mks)

……………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………..………………..…

…………………………………………………………………………………………………………………………….………..……………………

……………………………………………………………………………………………………………………………………………….……………

…………………………………………………………………………………………………………………….………………………………………

…………………………………………………………………………………………………………………….………………………………………

………………………………………………………………………………………………………….……………………………………………..…

……………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………….……

…………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………………………..

…………………………………………………………………………………………………………………………………………………………..

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…………………………………………………………………………………………………………………………………………………………..

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PROJECTION NO. 05

Name………………………………………………………. Index No…………………/…….

School……………………………………………………… Candidate’s Signature……………

Date ………………………………..

231/2

BIOLOGY

THEORY

Paper 2

2 Hours

Write your name and Index Number in the spaces provided above.

• This paper consists of two sections. Section A and Section B.


For Examiner’s use only.


1

2

3

4

5

8

8

8

8

8

6 20

7 20

8 20

TOTAL SCORE 80

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1. The diagram below shows the mammalian digestive system. Study it carefully and answer the


a) i) Name the parts labeled A and B. (2mks)

A………………………………………………………………………………………………………...………

B. ……………………………………………………………………………………………………………....

ii) How is the structure labeled A in the diagram adapted to carry out its function? (2mks)

…………………………………………………………………………………………..………………………………………….……………….....

……………………………………………………………………………………………………………………………………………………….....

b) i) Name the hormone secreted by the walls of part labeled C (1mk)

………………………………………………………………………………………………………………………………………………….….....

………………………………………………………………………………………………………………………………………………………..

ii) Explain the role of the hormone in b (i) above in digestion. (3mks)

……………………………………………………………………………………………………………………………………………………….....

………………………………………………………………………………………………………………………………………………….…….....

……………………………………………………………………………………………………...........................................................

..................................................................................................................................................................

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2. The diagram below represents a feeding relationship in an ecosystem.

a) Name the type of ecosystem represented by the above food web. (1mk)

……………………………………………………………………………………………………........................................................

……………………………………………………………………………………………………………………………………………………………

b) Name the organisms in the food web that

i) Are producers (1mk)

……………………………………………………………………………………………………......................................................

ii) Occupies the highest trophic level (1mk)

…………………………………………………………………………………………………….....................................................

c) i) Write a food chain that ends with the hawk as quaternary consumer. (1mk)

……………………………………………………………………………………………………………………………………………………..

ii) State two short term effects on the above ecosystem if all the small fish were killed.

(2mks)

……………………………………………………………………………………………………..........................................................

……………………………………………………………………………………………………..........................................................

……………………………………………………………………………………………………………………………………………………………

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d) How does oil spills lead to death of fish. (1mk)

………………………………………………………………………………………………….………………………………………………….....

…………………………………………………………………………………………………………………………………………………………

e) Name one other cause of water pollution apart from oil spills. (1mk)

…………………………………………………………………………………………………………………………………………………………..

………………………………………………………………………………………………………………………………………………………….

3. Study the flow chart below of a process that takes place in both plants and animals.

a) Name the above process. (1mk)

………………………………………………………………………………………………………………….………………………………….....

…………………………………………………………………………………………………………………………………………………………

.

b) i) In the above process name the chemical reaction represented by X. (1mk)

…………………………………………………………………………………………………….......................................................

…………………………………………………………………………………………………………………………………………………………..

ii) Name the part of the cell where the enzyme controlled reactions in b(i) above takes

place. (1mk)

…………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………….

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c) Name the products Z in

i) Plants (1mk)

……………………………………………………………………………………………………………………………………………………….....

…………………………………………………………………………………………………………………………………………………………..

ii) Animals (1mk)

………………………………………………………………………………………………………………………………………………….….....

…………………………………………………………………………………………………………………………………………………………

d) What would be the fate of pyruvic acid if oxygen supply is availed in the mitochondria of an

animal cell (2mks)

…………………………………………………………………………………………………………………………………………………….....

……………………………………………………………………………………………………………………………………………….…….....

…………………………………………………………………………………………………………………………………………………………

e) What is meant by the term oxygen debt? (1mk)

……………………………………………………………………………………………………......................................................

………………………………………………………………………………………………………………………………………………………..

4. a) Define multiple allelism and give an example. (2mks)

………………………………………………………………………………………………………………..……………………………………….....

……………………………………………………………………………………………………..........................................................

b) In Drosophila melanogaster the gene for eye colour is sex linked. The gene for red eye is

dominant. A cross was made between a homozygous red eye female and a white eyed

male. Workout the phenotypic ration of the F1 generation. (Use R to represent the gene for

red eyes.) (4mks)

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c) Suggest two reasons to explain why Drosophila melanogaster is the most preferred

organisms for studies in modern genetics. (2mks)

…………………………………………………………………………………………….……………………….………………………………….....

………………………………………………………………………………………………………………………………….….………………….....

…………………………………………………………………………………………………………………………………………………………….

5. An experimental set-up below was placed in the sun for some days. The rate of bubbles given off

per unit time, from the cut end of the water plant (Elodea) was measured. The results obtained are

shown in the table below.

a) i) Name the gas that was given off by the plant. (1mk)

…………………………………………………………………………………………………….....................................................

……………………………………………………………………………………………………………………………………………………….

ii) Name the biological process that the gas in a(i) produces. (1mk)

…………………………………………………………………………………………………….....................................................

……………………………………………………………………………………………………………………………………………………….

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b) What conclusion is drawn from the results obtained in this experiment? (1mk)

……………………………………………………………………………………………………......................................................

…………………………………………………………………………………………………………………………………………………………

c) You are provided with an electric bulb, a metre rule and a light meter. Briefly describe how

you would use this experimental set-up in the laboratory to demonstrate the effect of light

intensity on the rate photosynthesis. (4mks)

………………………………………………………………………………………………………………………………………………….…….....

…………………………………………………………………………………………………………………………………………………………....

…………………………………………………………………………………………………………………………………………………..…….....

……………………………………………………………………………………………………...........................................................

……………………………………………………………………………………………………...........................................................

d) Suggest one possible experimental error that may occur in this experiment. (1mk)

……………………………………………………………………………………………………........................................................

…………………………………………………………………………………………………………………………………………………………

SECTION B: (40 MARKS)

Answer question 6 Compulsory and either question 7 and 8 in the spaces provided after question 8.

6. An experiment was carried out to investigate the effect of heat on germination of seeds. Ten bags

each containing 60 pea seeds were placed in water-bath maintained at 850C. After an interval of two

minutes a bag was removed and seeds planted. The number that germinated was recorded. The

procedure used for pea seeds was repeated for wattle seeds. The results were tabulated as in the

table below.

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Time (Minutes) Number of seeds that germinated

Garden pea seeds Wattle seeds

0 – 2

2 – 4

4 – 6

6 – 8

8 – 10

10 – 12

12 – 14

14 – 16

16 – 18

18 – 20

20 – 22

60

60

44

40

36

11

2

1

1

0

0

0

0

1

2

28

36

41

44

47

49

49

a) Using a suitable scale and on the same axes, draw graphs of time in hot water against

number of seeds that germinated for each plant. (7mks)

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b) i) After how many minutes would you expect 50% of wattle seeds exposed in hot water to

germinate. (1mk)

……………………………………………………………………………………………………...................................................

………………………………………………………………………………………………………………………………………………………

ii) What was the minimum number of minutes after exposure of garden pea seeds to hot

water was there no germination. (1mk)

……………………………………………………………………………………………………......................................................

………………………………………………………………………………………………………………………………………………………..

c) From the graph, which of the two types of seeds was more sensitive to heat influence on

germination. Why? (1mk)

……………………………………………………………………………………………………......................................................

………………………………………………………………………………………………………………………………………………………..

………………………………………………………………………………………………………………………………………………………..

d) Explain why the ability for the:

i) Garden pea seeds to germinate declined with the time of exposure to heat. (3mks)

…………………………………………………………………………………………………………………………………………………………....

……………………………………………………………………………………………………...........................................................

……………………………………………………………………………………………………...........................................................

………………………………………………………………………………………………………………………………………………………..…..

ii) Wattle seeds to germinate increased with time of exposure to heat. (2mks)

………………………………………………………………………………………………….............................................................

……………………………………………………………………………………………………...........................................................

…………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………….

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e) What results would be expected if the temperature of water was maintained at

temperatures.

i) Above 850C (1mk)

…………………………………………………………………………………………………………………………………………………..….....

…………………………………………………………………………………………………………………………………………………………..

ii) At 50C (1mk)

…………………………………………………………………………………………………….......................................................

…………………………………………………………………………………………………………………………………………………………..

f) Apart from temperature state three internal factors necessary for seed germination. (3mks)

……………………………………………………………………………………………………..........................................................

……………………………………………………………………………………………………..........................................................

……………………………………………………………………………………………………..........................................................

…………………………………………………………………………………………………………………………………………………………….

7. a) Briefly describe the circulation of blood in a mammalian heart. (6mks)

b) Discuss the pumping mechanism of the heart. (14mks)

8. Describe the role played by growth hormones in growth and development in plants. (20mks)

……………………………………………………………………………………………………...........................................................

………………………………………………………………………………………………………………………………………..……………….....

……………………………………………………………………………………………………..........................................................

……………………………………………………………………………………………………...........................................................

……………………………………………………………………………………………………...........................................................

……………………………………………………………………………………………………...........................................................

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……………………………………………………………………………………………………...........................................................

……………………………………………………………………………………………………...........................................................

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……………………………………………………………………………………………………...........................................................

…………………………………………………………………………………………………………………………………………………………....

…………………………………………………………………………………………………………………………………………………………....

…………………………………………………………………………………………………………………………………….………………….....

…………………………………………………………………………………………………………………………………………………….….....

………………………………………………………………………………………………………………………………………………..……….....

……………………………………………………………………………………………………...........................................................

……………………………………………………………………………………………………...........................................................

……………………………………………………………………………………………………...........................................................

……………………………………………………………………………………………………...........................................................

……………………………………………………………………………………………………...........................................................

……………………………………………………………………………………………………...........................................................

……………………………………………………………………………………………………...........................................................

……………………………………………………………………………………………………...........................................................

……………………………………………………………………………………………………...........................................................

……………………………………………………………………………………………………...........................................................

……………………………………………………………………………………………………...........................................................

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PROJECTION NO. 06

NAME: ………………………………..………………………………. INDEX NUMBER: ……………………………….

SCHOOL: ………………………………………………………..…… CANDIDATES SIGNATURE: …………………..

DATE: ……………………………………………..

231/2

BIOLOGY

PAPER 2

2 Hours



• This paper consists of two sections; A and B.

• Answer ALL the questions in section A in the spaces provided.

• In section B, answer questions 6 (compulsory) and either question 7 or 8 in the spaces provided after question 8.


Section

Question

Maximum Score

Candidates Score

A

1 8

2 8

3 8

4 8

5 8

B

6 20

7 20

8 20

Total Score 80

SECTION A: (40MARKS)

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1. a) State three structural differences between arteries and veins (3mks)

………………………………………………………………………………………………………………………………………………………….

………………………………………………………………………………………………………………………………………………………….

………………………………………………………………………………………………………………………………………………………….

………………………………………………………………………………………………………………………………………………………….

………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………..

b) List two factors that aid in blood flow through the veins (2mks)

…………………………………………………………………………………………………………………………………………………………..

………………………………………………………………………………………………………………………………………………………..….

………………………………………………………………………………………………………………………………………………………..….

…………………………………………………………………………………………………………………………………………………………….

c) Name the proteins in the blood which are responsible for determining the blood group of a

person (2mks)

…………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………….

d) In a certain person, blood took long time to clot after a cut. What vitamin deficiency was the

person likely to have been suffering from? (1mk)

…………………………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………………………

2. a) What is carbon dioxide fixation in photosynthesis? (3mks)

…………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………....

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b) Explain how oxygen is formed in the process of photosynthesis (4mks)

………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………….…….

…………………………………………………………………………………………………………………………………………….…….

…………………………………………………………………………………………………………………………………………..……….

c) Other than carbon (IV) oxide, name another raw material for photosynthesis (1mk)

…………………………………………………………………………………………………………………………………………….……….

………………………………………………………………………………………………………………………………………………….….

3. Below is a cross section of the human spinal cord.

a) Name the parts labeled A and B (2mks)

A ……………………………………………………………………………………………………………….

B ………………………………………………………………………………………………………………..

b) State the function of the part labeled C (1mk)

………………………………………………………………………………………………………….…………………..………………………….

…………………………………………………………………………………………………………………………………………………….…….

c) Describe the reflex arc when a bare footed man steps on a sharp pin (5mks)

…………………………………………………………………………………………………………………………………….………………………

…………………………………………………………………………………………………………………………………………………………….

C

B

A

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…………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………….……………………

…………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………………………...

………………………………………………………………………………………………………………………………………………………………..

4. a) Name two disorders in humans caused by gene mutations (2mks)

………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………..…………………….

………………………………………………………………………………………………………………………………………………………...

b) What is meant by the term allele? (1mk)

………………………………………………………………………………………………………………………………………………………….

………………………………………………………………………………………………………………………………………….……………….

c) In a particular species of tropical beetle, the wings had either red or orange marks. A cross

between a red marked beetle with orange marked beetle produces offsprings with yellow marks

only. When F1 offsprings were selfed, they produced F2 generation in the ratio of

1 red : 2 yellow : 1 orange

i) Explain the absence of red and orange marks in F1 offspring’s (1mk)

……………………………………………………………………………………………………………………..………………………………….

……………………………………………………………………………………………………………………………..………………………….

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ii) Using a punnet square, show how the F2 generation was crossed. (Use letters R for red

marks and W for Orange marks) (4mks)

5. a) Describe the three characteristics of a population (3mks)

…………………………………………………………………………………………………………………………………………………………..

……………………………………………………………………………..…………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………..

………………………………………………………………………………………………………………………………………………….………

……………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………..

b) The table below gives information about an aquarium community which is ecologically

balanced.

Type of organism Weight in grams

Insect larvae 500g

Fishes 1,200g

Water Plants 5000g

Bacteria 10g

i) What do you understand by the term ecologically balanced? (1mk)

…………………………………………………………………………………………………………………….……………………………………..

……………………………………………………………………………………………………………………………………………………………

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ii) Construct a pyramid of biomass from the above data (3mks)

……………………………………………………………………………………………………………………………..…………………..……….

…………………………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………….……..…….

…………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………….

iii) Briefly describe the shape of the pyramid of biomass (1mk)

…………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………….


Answer question 6 (Compulsory) and either question 7 or 8 in the spaces provided after question 8

6. The table below shows the rate of enzyme activity at different pH values.

pH Rate of Product formation (mg/hr)

1

2

3

4

5

6

7

8

9

10

8.0

10.0

10.0

6.0

3.3

2.0

1.0

0.3

0.0

0.0

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a) Using a suitable scale, draw a graph of the rate of product formation against pH (6mks)

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b) Account for the rate of product formation between

i) pH 1 and 3 (2mks)

ii) pH 5 and 8 (2mks)

iii) pH 9 and 10 (2mks)

c) What is the optimum pH value for this enzyme (1mk)

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d) Suppose this enzyme is a digestive in what part of the alimentary canal would it be found (1mk)

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i) Give a reason for your answer (2mks)

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e) Apart from the pH, state four other factors that may affect the rate of enzyme activities (4mks)

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7. a) Describe how insect pollinated flowers are adapted to pollination (10mks)

b) Explain how seeds and fruits are adapted to wind and animal dispersal (10mks)

8. Explain how a finned fish is adapted to locomotion in water (20mks)

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PROJECTION NO. 07

231/2

BIOLOGY

Paper 2

Time: 2 Hours



• This paper consists of two sections. Section A and Section B.

• Section A consists of 40 marks and All questions in this section should be answered in the spaces provided in this question paper.




1

2

3

4

5

8

8

8

8

8

6 20

7 20

8 20

TOTAL SCORE 80

of 744



Answer ALL questions in this section in the spaces provided.

1. Shown below is a section through the mammalian nephron.

a) Name the structures labeled - (2mks)

A …………………………………………………………………..……………………………………………………………………..

N ……………………………………………………………………………………………………………………………………………

b) Name all structures in a nephron which are normally present in the cortex region of

kidney. (1mk)

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c) Which region in the Nephron deals with conservation of body water (1mk)

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d) Name one hormone that has an effect on part labelled X. (1mk)

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e) How is part labeled N adapted to its function. (3mks)

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2. a) In a certain family with two children, one child is blood group B while the other one is

blood group O. Work out the genotype of the two children if the mother is blood group A

and father group B. (4mks)

b) What would be the phenotypic ration of the F1 generation? (1mk)

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c) What is haemolytic disease of the new-born (Erythroblastosis foetalis) (3mks)

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3. a) State two limitations of using fossil records as evidence of evolution. (2mks)

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b) What is the significance of isolating mechanisms in the process of evolution? (3mks)

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c) Describe geographical distribution as an evidence of evolution. (3mks)

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4. The results in the table below shows the effects of some conditions for seed germination.

In each experiment, all other environmental conditions were kept constant, except for the one being

investigated.

Experiment Treatment % germination

I - Seeds placed in tightly closed

container with pyrogallic acid.

0

II i) Seeds kept in source of light.

ii) Seeds kept in dark cupboard

96

97

III i) Seeds kept in a refrigerator at 40C

ii) Seeds kept in an oven at 600C

iii) Seeds kept at 350C

0.5

0

92

IV i) Dry seeds in closed containers

ii) Moist seeds in closed container

0

87

a) i) What was the purpose of pyrogallic acid in experiment (i) (1mk)

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ii) State the aim of the experiment (ii) (1mk)

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b) i) Account for the results obtained in experiment set-up (iii). (3mks)

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ii) State why 100% germination was not achieved in experiment (iv) (ii) (1mk)

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c) Of what biological significance is the condition necessary for germination been investigated

by experiment (iv). (2mks)

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5. A student obtained a castor oil petiole, measuring 4cm long, which was split half way to obtain 4

flaps. The two pieces were then placed in solutions of different concentrations in a beaker, for 10

minutes. The appearance after 10 minutes is as shown.

Piece in A Piece in B

a) Account for the appearance of the pieces in solutions A and B (6mks)

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b) State the significance of the biological process involved in the experiment. (2mks)

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.


Answer question 6 (compulsory) in the spaces provided either question 7 or 8 in the spaces provided after

question 8.

6. The data below was obtained from an experiment designed to measure the velocity of flow of water

during the course of a single day in the xylem of two trees of the same species.

Time of day/hr 0300 0600 0900 1200 1500 1800 2100 2400 0300 0600

Velocity of

flow/cm hr-1

Eucalyptus

species

0 45 125 140 135 85 45 25 5 0

Acacia species - 5 105 135 110 45 30 25 10 0

a) Using the same axes, draw graphs to show the velocity of flow against time. (8mks)

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b) At what time of the day was the velocity of flow same for the species? (1mk)

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c) Account for the shape of the graphs of eucalyptus. (4mks)

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d) What forces move the water through the plant? (4mks)

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e) Determine the rate of flow at 1900 hours. (2mks)

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f) Suggest two features of Acacia that lead to the difference in the velocity of flow. (2mks)

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7. Describe how various factors regulate population growth in an ecosystem. (20mks)

8. a) Describe how the structure of the eye is adapted to its function. (16mks)

b) Identify two defects of the eye and how they can be rectified. (4mks)

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PROJECTION NO. 08

Name:....................................................... Index No.: ........................................

Candidate’s Signature: .................

Date: ................................................

231/2

BIOLOGY

Paper 2

Time: 2 hours

Kenya Certificate of Secondary Education

Paper 2

BIOLOGY

Instructions to Candidates

❖ Write your name and index number in the spaces provided above.

❖ Sign and write the date of the examination paper.

❖ Answer ALL the questions in the spaces provided in the question paper.

❖ ALL working MUST be clearly shown where necessary.

❖ Mathematical tables and silent electronic calculators may be used.

CANDIDATE’S SCORE

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1. The diagram below shows a life cycle of a cockroach

(a) Name the hormone that would be at high concentration during the first and second

week and their functions.

(i) First week (2mks)

Hormone ……………………………………………………………………………..…………………………………

Function………………………………………………………………………….…………………………………………

(ii) Second week (2mks)

Hormone ……………………………………………………………………………………………………………………

Function ………………………………………………..……………………………………………………………………

(b) Name the structure that produces hormone named in a (ii) above (1mk)

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c) Name the process represented by the life cycle above (1mk)

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d) State two importance for the process named in (c) above (2mks)

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2. The diagram below represents part of a geasous system in a grasshopper.

P Q

a) Name the structures labeled P and Q

P……………………………………………………………………………………..(1mk)

Q …………………………………………………………………………………….(1mk)

b) State the function of the structure labeled P (1mk)

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c) Describe the path taken by carbon (IV) oxide from the tissues of the insect the

atmosphere (3mks)

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d) How is the structure labeled Q adapted to its functions (2mks)

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3. The set up below illustrates an experiment to demonstrate a certain biological process,

before the addition of the yeast suspension the glucose solution was first boiled and then

cooled at 40oC.

a) What was the aim of the experiment? (1mk)

……………………………………………………………………………………………………………………………………

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b) What observations would you make in the tubes a few minutes after the experiment

begun (2mks)

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c) Explain the observations made in (b) above (2mks)

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d) Why was glucose solution boiled before cooling at 40oC (1mk)

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e) How can you set up a control experiment for the above (1mk)

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.

4. The following are short messages (sms) on cell phone communication between Mrs.

Mkenzie and her husband. They can be used as analogies of gene mutation

Intentended message Actual message

1. I want a drive I want a driver

2. Yesterday was my shopping day Yesterday was my hopping day

3 My skirt was stolen My shirt was stolen

4 Tommorrow I will be visiting my team Tommorow I will be visitng my mate

a) For each of these messages identify the type of gene mutation illustrated (4mks)

1……………………………………………………………………………………………

2……………………………………………………………………………………………

3……………………………………………………………………………………………

4……………………………………………………………………………………………

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b) State one example of chromosomal mutation that lead to

i) Change in chromosome structure (1mk)

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ii) Change in chromosomal number (1mk)

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c) Explain why genetic counseling is termed as one practical application of genetics

(2mks)

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5. The following is a photograph of s dissected mammal. Study the photograph and answer the

questions that follows

R

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T

a) Name the structures labeled R,S and T (3mks)

R…………………………………………………………………………………………………….

S…………………………………………………………………………………………………….

T…………………………………………………………………………………………………….

b) On the photograph, label and name the site of production of vitamin K (1mk)

………………………………………………………………………………………………………………………………………………….

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c) State one function of the following parts (2mks)

S…………………………………………………………………………………………………………………………………………………..

…………………………………………………………………………………………………………………………………………………….

T

…………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………

d) i) State the sex of the dissected mammal (1mk)

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ii) Give a reason for your answer in d (i) above (1mk)

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Answer question 6(compulsory) then choose any between question 7 and 8

6. The figure below shows the changes in the concentration of various substances in a river

following the discharge of untreated sewage into it. Study it and answer the questions that

follow

a) Account for the changes in the concentration of:

i) Organic matter (3mks)

…………………………………………………………………………………………………………………………………………

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ii) Nutrient ions (2mks)

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iii) Dissolved oxygen (4mks)

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b) Describe the changes you would expect to observe with respect to:

i) Fish population (3mks)

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ii) Water plants and photosynthetic algae (4mks)

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c) State four ways of controlling the type of pollution illustrated above (4mks)

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7. Describe how the following types of plants are adapted to their habitats:

a) Mesophytes (10mks)

b) Halophytes (5mks)

c) Hydrophytes (5mks)

8. Discuss the adaptations of the human eye to its functions (20mks)

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PROJECTION NO. 09

Name:……………………………………………………... Index No. …………………………

School:……………………………………………………. Candidate’s Signature…………………… Date: …………………………

231/2

BIOLOGY

PAPER 2

(THEORY)

of 744


TIME: 2 HOURS

INSTRUCTIONS TO CANDIDATES:-

• Write your name and index number in the spaces provided above.

• Sign and write the date of examination in the spaces provided above.


• Answer all the questions in Section A in the spaces provided.

• In section B, answer question 6 (compulsory) and either question 7 or 8 in the spaces provided after

question 8.

For Examiner’s Use Only:-

Section Question Maximum score Candidates score

A 1

2

3

4

5

8

8

8

8

8

B 6

7 or

8

20

20

20

TOTAL SCORE 80

of 744


1. The diagram below represents part of a cockroach gaseous exchange system.

a) State the function of the part labelled M (1 mark)

…………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………….

b) Suggest how the part M is adapted to the gaseous exchange function (3 marks)

…………………………………………………………………………………………………………………………………………………………….

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c) How does the movement of oxygen in an insect and mammals from atmosphere to the tissue

of its body differ (4marks)

………………………………………………………………………………………………………………………………..……………………

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N

M

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2. The following chart below shows blood transfusion pathway

a) What five conclusions can you draw from the flow chart (5marks)

………………………………………………………………………………………………………………………………………………………….…

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b) Why is the knowledge of blood groups necessary before blood transfusion? (1 mark)

…………………………………………………………………………………………………………………………………………………………….

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c) A part from knowledge of blood groups, state two precautions that must be observed during

blood transfusion (2 marks)

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…………………………………………………………………………………………………………………………………………………………….

AB

A

B

O

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3. The genetic disorder haemophilia is due to a recessive sex linked gene. A man who is haemophiliac

married a woman who is a carrier for the condition.

a) Using letter (H) to represent normal condition and (h) to represent haemophiliac condition.

i) What is the genotype of the man and the woman? (2 marks)

Man ………………………………………………………………………..

Woman ……………………………………………………………………..

ii) Work out across between the man and the woman (3marks)

b) What is the chances that both the first and the second sons will be haemophiliac? (2 marks)

……………………………………………………………………………………………………………………………………….……………………

……………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………….

c) Haemophilia is most common in the males than females humans. Explain. (1 mark)

………………………………………………………………………………………………………………………………………….…………………

…………………………………………………………………………………………………………………………………………………………….

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4. The diagram below shows different groups of organisms and their biomass.

a) Define the term biomass (2 marks)

………………………………………………………………………………………………….…………………………………………………

…………………………………………………………………………………………………………….……………………………………….

b) Account for the decrease in biomass in the successive group of organisms (3 marks)

…………………………………………………………………………………………………………………………………………………….

………………………………………………………………………………………………………………………………………..…………….

……………………………………………………………………………………………………………………………………….…………….

………………………………………………………………………………………………………………………………………………………

c) Describe how energy from the sun is made available for carnivore II (3 marks)

……………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………..……

…………………………………………………………………………………………………………………………………………………………..

………………………………………………………………………………………………………………………………………………………….

5. Cell of a certain herbaceous plant were found to have an average diameter of 2.5m the cells were

put in varying concentrations of salt solutions. The average diameter of the cells in each solution

was determined and the results were recorder as shown in the table below.

Carnivore II

Carnivore I

Herbivore

Green plants

2

15

300

1200

Biomass (g/cm3)

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Concentration of

salt solution %

Diameter of cells.

μ m

1

5

10

15

5.0

4.0

3.0

2.0

a) From the results above, determine the cell sap concentration (1 mark)

……………………………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………………………..

b) Give an explanation for the average diameter of the cells placed in the following salt concentration

compared to the normal diameter of the cells.

i) 1 % salt solution (3 marks)

…………………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………

ii) 15 % salt solution (3 marks)

………………………………………………………………………………………………………………………………………………..

………………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………………

Give the term used to describe salt solution whose concentration is the same as cell sap. (1 mark)

………………………………………………………………………………………………………………………………………………….

………………………………………………………………………………………………………………………………………………….

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SECTION B (40 .MARKS)

Answer question 6 (compulsory) and either 7 or 8 in the space provided after question 8.

4. In the experiment, the population growth of yeast cells in a Petri dish was determined over a period of 75

minutes. The results below were obtained.

Time in minutes Number of yeast cells

0 4

5 6

10 8

15 10

25 30

30 50

35 80

40 120

45 140

50 150

55 160

65 166

75 166

a) Using a suitable scale, plot a graph of number of cells against time in minutes (6 marks)

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b) Name the type of the curve you have drawn above (1 mark)

…………………………………………………………………………………………………………………………………………………………..

…………………………………………………………………………………………………………………………………………………………..

c) Determine the number of yeast cells after 37 minutes (1 mark)

…………………………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………………………

d) After how long was the population of yeast cells 144? (1 mark)

………………………………………………………………………………………………………………………………………………….…………

…………………………………………………………………………………………………………………………………………………………….

e) Work out the rate of cell division between 32 minute and 42 minute (2 marks)

……………………………………………………………………………………………………………………………………………………….……

…………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………….

f) Account for the shape of graph between 45th minute and 60th minute (3 marks)

…………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………….

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…………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………………………

g) In a field study to estimate the population of grasshoppers in the school field of 4 km2, 60

grasshoppers were caught using sweep nets, marked with red paint and released back to the field.

The following day students went back with their sweep nets and caught 100 grasshoppers, in which

20 were found to be already marked.

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i) Calculate the population size of grasshoppers in the field (2 marks)

ii) Calculate the population density of the grasshoppers in the field (2 marks)

iii) What factors would maintain the population of grasshoppers and yeast cells at the carrying

capacity. (2 marks)

………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………

7. Describe the various evidences to support organic evolution (20 marks)

8. a) Describe how the heart beat is controlled and maintained (10 marks)

b) Describe the structure and function of thrombocytes (10 marks)

………………………………………………………………………………………………………………………………….…………………………

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PROJECTION NO. 10

NAME: …………………………………………………..…………… INDEX NO:……….……………………………..…………..

SCHOOL………………………………….……………………..…… DATE……………..……………………………………………

CANDIDATE’SIGN…………………………..…………………….

231/2

BIOLOGY

PAPER 2 (THEORY)

TIME: 2 HOURS

INSTRUCTIONS TO THE CANDIDATES

• Write your name, school and index number in the spaces provided above.




• In section B, answer question 6(compulsory) and either question 7 or 8 in the spaces provided after

question 8.

For Examiner’s Use only:-

SECTION QUESTION MAXIMUM SCORE CANDIDATE’S SCORE

A 1

2

3

4

5

8

8

8

8

8

B 6

7

8

20

20

20

TOTAL SCORE 80

SECTION A (40MRKS)

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Answer all question in the spaces provided

1. The figure below shows the embryo-sac before fertilization.

(a) Identify the structures labelled A and B . (2mrks)

A ………………………………………………………………..……………….………..…….……………………………

B …………………………………………………………………………………………………………………………………

(b) Identify the structures labelled in the diagram that will develop into the following after

fertilization.

i) Embryo……………………………………………………………….…………...……………………… (1mrk)

ii) Endosperm.……………………………………………………………………….………….……………. (1mrk)

(c) State the ploidy of each the following nuclei after fertilization.

i) C ……………………………………………………………………………………………………………… (1mrk)

ii) D …………………………………………………………………………………………………….………… (1mrk)

(d) Briefly outline the process of “double” fertilization in flowering plants. (2mrks)

…………………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………..……..

…………………………………………………………………………………………………………………………………………………….

2. (a) Name two substances which are found in the intercellular air spaces in a green leaf during a hot

sunny day. (2mrks)

……………………….……………………………………………………………………………………..…………………………………………….

……………………….……………………………………………………………………………………..…………………………………………….

E

D

B

C

A

Generative

nucleus

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(b) Name the gaseous exchange structure found in the:

i) Stem of a mesophyte plant……………………………………………..………………………………………………(1mrk)

ii) Root of aquatic halophytes………………………………………………………………..…………………(1mrk)

iii) Terrestrial insects……………………………………………………………………………………..…………..(1mrk)

(c) State three ways in which the gill filaments are adapted to their functions. (3mrks)

…………………………………………………………………………………………………………………………………………………………..

…………………………………………………………………………………………………………………………………………………….…..

…………………………………………………………………………………………………………………………………………………….…..

………………………………………………………………………….. …………………………………………………………………………..…

…………………………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………………………..

…………………………………………………………………………………………………………………………………………………………….

3. In cats, sex is determined by X and Y chromosomes in the same way as humans. One gene for coat

colour in cats is present on the X chromosome but not on the Y chromosome. The gene has two

alleles orange (B) and black (b). Female cats that are homozygous for the Xb allele have black coats;

female cats that are heterozygous have tortoise-shell coats (orange with dark patches).

(a) Give the genotype of:

(i) A female cat with tortoise shell coat. (1mrk)

…………………………………………………………………………………………………………..………………………………………………..

………………………………………………………………………………………………………...………………………………………………….

(ii) A male cat with an orange coat. (1mrk)

…………………………………………………………………………………………………………………………………………………………..

…………………………………………………………………………………………………………………………………………………..………..

(iii) A male cat with a black coat. (1mrk)

…………………………………………………………………………………………………….………………………………………………………

………………………………………………………………………………………………………………………………………………………………

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(b) A black coated male cat is mated with a tortoise- shell coated female cat. Use a punnet

square to determine the genotypic and phenotypic ratios of the kittens that could be produced

by this cross . (5mrks)

4. In a Savanna grassland ecosystem, the following organisms were identified; grasses, squirrels,

gazelles, lizards, insect larvae, wild dogs, snakes, hawks, vultures and lions, Energy flow in the

ecosystem was also determined as follows.

HEAT LOSS TO THE

ENVIRONMENT

1500kJ 320kJ

Producers Primary

Consumer

Secondary

Consumer

Tertiary

Consumers

A 500kJ B

X

C 100kJ 1000kJ

1500kJ

2000kJ

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a) Define the term ecosystem (1mrk)

…………………………………………………………………………………………………………………………………………..………………

………………………………………………………………………………………………………………………………………………..………….

…………………………………………………………………………………………………………………………………………………………....

b) Name the process through which:

i) Producers convert sun’s energy into chemical energy (1mrk)

………………………………………..………………………….…………………………………………………………………………………………..

………………………………………………………………………………………………………………………………………………………………..

ii) Living organisms convert chemical energy into heat energy lost to the environment (1mrk)

……………………………………………………………………………………………………………………………………………………..

……………………………………………………………………………………………………………………………………………………..

c) Identify organism X (1mrk)

………………………………………………………………………………………………………………………………………………………………..

……………………………………………………………………………………………………………………………………………………………….

d) Determine the amount of energy represented by A and B (2mrks)

A ………………………………………………………………………………………………………………………….………

B …………………………………………………………………………………………………………………………………….

e) If 75% of the energy in the tertiary consumers is lost as heat. Calculate the amount of energy

represented by C (2mrks)

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5. Three potted seedlings labelled R, Sand T were treated as follows:

R- Tip of seedling was cut off.

S- Tip was covered with aluminium foil cap.

T- Tip was left intact

The seedlings were placed in, a box which had a hole on one side and painted black on the inside.

The experiment was left for four days.

a) (i) State the expected observations (3mrks)

R ………………………………………………………………………………………………….…………………………….

S …………………………………………………………………………………………………………………..…………..

T ………………………………………………………………………………………………………………….……………..

ii) Explain the observations in a (i) above

R ………………………………………………………………………………………………………………………………… (1mrk)

……………………………………………………………………………………………………………………………………

S …………………………………………………………………………………………………………………………….………… (2mrks)

………………………………………………………………………………………………………………………………………..

T ………………………………………………………………………………………………………………………………………… (2mrks)

………………………………………………………………………………………………………………………………….…

Light

Aluminium foil cap

Box

R S T

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SECTION B- (40MRKS)

Answer questions 6(compulsory) and either 7 or 8 in the spaces after question 8.

6. An experiment was set up to investigate the effect of light on the rate of photosynthesis in the shoot

of a water weed. The shoot was immersed in a 2% sodium hydrogen carbonate solution. The gas given

off by the shoot was collected for five minutes at different light intensities and the volume measured.

The results obtained are shown in the table below.

Light intensity(arb units) 1 2 3 5 10 20 30 40 50

Gas collected (cm3/5minutes) 0.35 0.6 0.85 1.20 1.55 1.70 1.80 1.79 1.79

Using the data given in the table, plot a graph of volume of the gas collected against the light intensity

(6mrks)

b) Account for the rate of gas production in the following intervals of light intensity.

i) 1 - 10 (2mrks)

………………………………………………………………………………………………………………………………………………...

………………………………………………………………………………………………………………………………………………..

………………………………………………………………………………………………………………………………………………..

………………………………………………………………………………………………………………………………………………...

…………………………………………………………………………………………………………………………………………………...

ii) 30 - 50 (2mrks)

…………………………………………………………………………………………………………………………………………………………..

…………………………………………………………………………………………………………………………………………………………..

………………………………………………………………………………………………………………………………………………………..…..

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c) What is the use of sodium hydrogen carbonate in this experiment. (1mrk)

…………………………………………………………..………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………….

d) State the products of light stage of photosynthesis. (2mrks)

…………………………………………………………..………………………………………………………………………………………………

…………………………………………………………..……………………………………………………………….………………………………

……………………………………………………………………………………………………………………………………………………………

e) State the functions of each of the products of the dark stage of photosynthesis in man (3mrks)

…………………………………………………………..……………………………………………………………………………………………….

…………………………………………………………..………………………………………………………………………………………………..

…………………………………………………………..………………………………………………………………………………………………..

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f) Why are plants referred to us as producers in an ecosystem. (2mrks)

…………………………………………………………..…………………………………………………………….…………………………………

…………………………………………………………..……………………………………………………………………..…………………………

(g) Other than light intensity, name two other factors that affect the rate of photosynthesis. (2mrks)

…………………………………………………………..……………………………………………………………………………………………

………………………………………………….………..…………………………………………………………………………………………..

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7. a) Define the term secondary thickening (2mrks)

b) Briefly describe how secondary thickening occurs in woody plants (14mrks)

c) i) State two ways in which growth in plants is different from that in animals (2mrks)

ii) State how ecdysis affects the growth of insects (2mrks)

8. a) State five differences between aerobic and anaerobic respiration. (5mrks)

b) Discuss the application of anaerobic respiration in industry and at home (15mks)

……………………………………………………………………………………………………………………………………………………………….……..

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PROJECTION NO. 11

NAME………………………………………………………….INDEX NO………………………

SCHOOL…………………………………………………….. DATE……………………………

SIGN…………………………….

231/2

BIOLOGY

PAPER 2

TIME: 2 HOURS



o Answer all questions in section A in the spaces provided

o Section B: Question 6 is compulsory, Answer either question 7 or 8

FOR EXAMINERS USE ONLY

Section Question Maximum score Candidate

score

A 1

2

3

4

5

8

8

8

8

8

B

6

7

8

20

20

20

TOTAL 80

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1. A human gene which is Y-linked controls the length of hair on male ears. One allele

produces non-hairy ears while the other produces hairy ears, (hairy pinna).

(a) What are alleles (1mark)

………………………………………………………………………………………………

……………………………………………………………………………………………....

(b) If a man with hairy ears/pinna marries, work-out the phenotypes of his children.

(Use letter h to represent gene for hairy pinna). (4 marks)

………………………………………………………………………………………………......................................

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…………………………………………………………………………………...................................................

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…………………………………………………………………………………………………………………………………..

(c) Explain why this trait is not observed in females (2marks)

…………………………………………………………………………………………………………………………….......

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(d) Give one other trait in man that is Y—linked (1mark)

……………………………………………………………………………………………………………..…………….......

...................................................................................................... ..................................

2. (a) The graph below represents the growth pattern of animals in a certain phylum

Growth

In size

Time

(i) Name the phylum showing the above growth pattern (1mark)

………………………………………………………………………………………………

………………………………………………………………………………………………

(ii) State the type of growth shown (1mark)

………………………………………………………………………………………………

………………………………………………………………………………………………

(iii) Explain the growth pattern illustrated by the graph (3marks)

………………………………………………………………………………………….……………………………….......

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(b) Explain the meaning of

(i) Growth

………………………………………………………………………………….. (1mark)

……………………………………………………………………………………………………

(ii) Development

………………………………………………………………………….. …………. (1mark)

……………………………………………………………………………………………………

(iii) Cleavage………………………………………………………………………………………. (1mark)

………………………………………………………………………………………………………………………….…

3. In an experiment some slices were cut from a living potato tuber and were immersed in

distilled water for one hour. After that the slices were immersed in a concentrated salt

solution for another one hour. The slices were taken out of the liquid, weighed and

immersed again in the liquid at regular intervals. The results are shown in the graph

below. Point L shows the beginning of the experiment.

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a) Give the name given to the condition of the cells of the slices at point (1mark)

……………………………………………………………………………………………………………………….………

………………………………………………………………………………………………………………………………..

b) (i) find the change in weight between L and M (1mark)

…………………………………………………………………………………………………………..……………….......

........................................................................................................................................

............................................................................................................................. ...........

(ii) Which process brings about this change in weight? (1mark)

……………………………………………………………………………………………….....................................

............................................................................................................................. ...........

........................................................................................................................................

(c) Explain the condition of the cells at point N. (2mark)

……………………………………………………………………………………………………………….………….......

........................................................................................................................................

............................................................................................................................. ...........

........................................................................................................................................

(d) The slices were removed from the concentrated salt solution at point P and washed

in distilled water. Draw a curve on the graph, to show what would happen in the next

one hour in the third section. (1mark)

(e) State two characteristics of active transport (2marks)

…………………………………………………………..……………………………………………………………….......

............................................................................................................................. ...........

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4. (a) Explain how carbon (IV) oxide produced by respiring mesophyl cells of flowering

plants reaches the atmosphere (4 marks)

……………………………………………………………………………………………………………..………………….......

..............................................................................................................................................

...................................................................................................................................... ........

…………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………

(b) How are submerged hydrophytes adapted for gaseous exchange (2marks)

……………………………………………………………………………………………….....................................

....................................................................................................................................... .

............................................................................................................................. ...........

……………………………………………………………………………………………………………………...............

............................................................................................................................. ...........

(c) State 2 respiratory diseases in Man (2marks)

………………………………………………………………………………………………......................................

............................................................................................................................. ...........

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5. The following figures are anterior views of two vertebrae

a) Identify the vertebra (2marks)

K………………………………………………… L……………………………………………

b) State where vertebra K is located in human body (1mark)

……………………………………………………………………………………………………………………………….

c) Name two parts labeled X and Y in vertebrae L (2marks)

X…………………………………………………………..…… Y…………………….………………………………..

d) How is vertebra K adapted to its function (3marks)

……………………………………………………………..…………………………………………………………….......

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........................................................................................................ ................................

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6. An investigation was carried out between 2003 and 2012 to study the changes of fish

population in a certain small lake. Four species of fish, T, W, M, P were found to live in

this lake. In 2004 a factory was built near the lake raising the average temperature from

25oC to 30oC. In 2005 sewage and industrial waste from a nearby town was diverted

into the lake. 2007, discharge of hot water, sewage and industrial waste into the lake

was stopped. The fish population during the period of investigation are shown in the

table below.

Fish species 2003 2005 2007 2009 2010 2011 2012

T 5900 200 17 100 700 4300 8000

W 300 25 8 19 60 400 508

M 30 120 0 0 0 0 0

P 4300 260 25 30 35 510 807

(a) (i) In which year were the fish population lowest? (1mark)

………………………………………………………………………………………………………………………………....

……………………………………………………………………………………………………………………….…………..

(ii) State the factors that might have caused the lowest fist population during the year

you have stated in (a)(i) above (3marks)

…………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………

(iii) Explain how each factor you have stated in (a)(ii) above could have brought about

the changes in fish population (6marks)

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(b) (i) What is the difference in the rate of population recovery of species T and P?

(3marks)

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(ii) Suggest two biological factors that could have led to this difference (2marks)

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(c) (i) State a method that might have been used in estimating the fish population in the

lake? (1mark)

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(ii) State one advantage of the method you have stated in (c) (i) above (1mark)

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(iii) State three limitations of the method named in (c) (i) above. (3marks)

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7. How is the mammalian skin adapted to its functions (20 marks)

8. (a) Explain the role of Auxin in Geotrophic response in plants (5 marks)

(b) Describe other roles of hormones in the growth and development of plants

(15 marks)

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PROJECTION NO. 12

Name: …………………………………… Index No: ……………………..……………..

Candidate’s Signature:…………………………….

Date: ……………….……………..…

231/2

BIOLOGY

Paper 2

Time: 2 Hours


BIOLOGY

Paper 2

Time: 2 Hours







question 8.


SECTION QUESTIONS MAXIMUM SCORE CANDIDATE’S SCORE

A 1

2

3

4

5

8

8

8

8

8

B 6

7

8

20

20

20

TOTAL SCORE 80

This paper consists of 8 printed pages. Candidates should check to ascertain that

all pages are printed as indicated and that no questions are missing.

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Answer ALL the questions in this section in the spaces provided.

1. The figure below shows apparatus at the start of an experiment to investigate the digestion

of an emulsion of fat droplets in water by enzyme A.

The pH indicator is green in a pH of 7, blue when the pH is above 7 and red when it is

below 7. The apparatus is kept at 40oC for 20 minutes during which time the indicator

changes from green to red.

(a) Describe how the products of fat digestion enter a person’s blood. (1mk)

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(b) (i) State the identity of enzyme A. (1mk)

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(ii) Explain why the apparatus was kept at 40oC. (1mk)

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(c) Name the products of digestion of the emulsion by enzyme A. (2mks)

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(d) Describe the process which led to the change in pH (3mks)

Partially permeable

membrane

Emulson of fat droplets in water +

Enzyme A

Water + pH indicator

Tightly tied

Partially permeable

membrane

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2. Study the diagram below and answer the questions that follow.

(a) Name the part labelled E. (1mk)

………………………………………………………………………………………

(b) What are the functions of the part labelled A. (2mks)

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(c) Which part of the structure responds to:

(i) Progesterone ………………………………………………………………..

(1mk)

(ii) Oxytocin ………………………………………………………………….. (1mk)

(d) Which type of cell division occurs in structure B and not structure labeled E.

………………………………………………………………………………………

(1mk)

(e) State two functions of testosterone (2mks)

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A

B

E

B

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3. The hemophilia is an X- linked recessive condition. The following pedigree shows a

portion of a family in which members have hemophilia. Use H for non-hemophilia

h for hemophilia.

(a) Identify the genotypes of parents A and B.

A……………………………………………………………………….. (1mk)

B………………………………………………………………………. (1mk)

(b) What is the genotype of offspring number 1 (1mk)

………………………………………………………………………………………

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(c) A carrier woman marries a hemophiliac man. What is the probability that the

couple will have a son who is hemophiliac show your working. (4mks)

Normal male

Haemophiliac

male Normal female

Normal

carrier Haemophiliac

female

A B

2 1

4

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(d) Name one defect of non-disjunction chromosomal mutation (1mk)

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4. The diagram below shows a front view of the iris and pupil of the eye.

(a) Complete the table below to show what happens to the structure shown when the

eye is in. (6mks)

Structure Darkness Bright light

Radial muscles

Circular muscles

Size of pupil.

(b) Explain how myopia can be corrected. (2mks)

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5. The diagram below represents the direction of flow of water over the gills of a fish and

the flow of blood in a capillary in the gills the percentage oxygen in solution at points A,

B, P, Q and R is given in the table below the diagram. The percentage hemoglobin

saturation is also given at positions P, Q and R.

Radial muscle

Pupil

Circular muscle

Water

A B

Q P R

Blood from heart Blood to blood

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(a) Why is the percentage of oxygen lowest at P? (1mk)

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(b) State with reasons, what this data suggest what will happen to oxygen in the water at

position B ? (2mks)

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(c) Why is the percentage of oxygen, in solution lower at R than at Q ? (1mk)

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(d) Suppose the direction of blood was opposite the above, suggest the disadvantage of

this arrangement as compared to the one above. (1mk)

………………………………………………………………………………………………

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(e) The principle whereby the blood flows in the opposite direction to that of another

fluid is known as counter-current effect (flow). Give two examples where this effect

occurs in the human body (2mks)

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(f) Name any structure of gaseous exchange in the leaves of plants. (1mk)

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Position % oxygen in solution % Hb saturation with O2

A 10 ____

B 7 ____

P 4 55

Q 7 85

R 6 95

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Answer question 6(compulsory) and either question 7 or 8 in the spaces provided after

question 8.

6. The relationship between oxygen concentration, sugar consumption and potassium ion

uptake in isolated wheat roots was determined. The results obtained were tabulated as

shown below. The loss of sugar and potassium uptake or gain are in arbitrary units.

(a) Plot graphs of sugar loss and potassium ions gain against oxygen concentration on

the same axes. (6mks)

(b) Name the process by which potassium ions is taken by the roots. Give reason for your

answer (4mks)

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(c) Account for sugar loss and potassium ions gain.

(i) 0% oxygen concentration (2mks)

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(ii) Between 5% and 20% oxygen concentration (2mks)

………………………………………………………………………………………

Percentage oxygen in aerotun stream

0 5 10 15 20 30 100

Sugar loss 15 20 43 45 45 44 43

Potassium ion gain 5 55 70 75 75 72 70

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(d) Suggest two factors necessary for the above process apart from oxygen (2mks)

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(e) State two ways by which the process above can be stopped (2mks)

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(f) Name two main areas in a mammalian body where the above process occurs. (2mks)

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7. Determine how the differentiated structures in the mammalian skin are adapted to the

functions. (20mks)

8. State and explain how various hormones regulate growth and development of plants.

(20mks)

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PROJECTION NO. 13

Name:……………………………………..……... Index. No. ………………..…………

Candidate’s Signature………………….……

Date: …………………….……………

231/2

BIOLOGY (THEORY)

PAPER 2

TIME: 2 HOURS


• Write your name,school index number, date of examination and sign this paper in the spaces

provided above.

• This paper consists two sections A and B

• Answer All the questions in sections A in the spaces provided .

• In section B, answer question 6 (compulsory) and either question 7 or 8 in the spaces



SECTION A

Section Questions Maximum score Candidates score

A 1 8

2 8

3 8

4 8

5 8

B 6 20

7 20

8 20

TOTAL 80

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(40 MARKS)

Answer all questions in this section in the spaces provided.

1.a) Define the term mutation. (1mk)

...……………………………………………………………………………………………………

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b) A couple, George and Grace had a son who was suffering from haemophilia even though

none of them showed signs of haemophilia.

i) State the genotype of George and Grace. (2mks)

………………...…………………………………………………………………………………….

………………………………………………………………………………………………………

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ii) Using a genetic cross work out the genotype of the couple’s son. (4mks)

c) What are linked genes? (1mk)

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2. An experiment was set up to investigate the effect of unilateral light on the growth of oat

coleoptile. The diagrams in the table below represent the experimental set ups at the start, and at

the end of the experiment.

Key: Rays of light

a)

Account

for the

results in

the experimental setup A. (3mks)

……………………………………………………………………………………………………..

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Set up Start of experiment Results

A

B

C

D

E Blade of mica

Blade of mica

Aluminium foil

cap

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b) Explain the purpose of experimental set ups B and C. (3mks)

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c) Explain the results in experimental set ups D and E. (2mks)

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3. Three pieces of potato cylinders of equal length were placed in three solutions of different

concentrations.

The set ups were left to stand for 45 minutes. The results were recorded in the table below.

Solution Initial length of cylinder (mm) Final length of cylinder (mm)

A 40 40

B 40 38.5

C 40 41

a) Describe the nature of solution A in relation to the concentration of the potato cells. (1mk)

………………………………………………………………………………………………………

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b) Explain the observation that was made on the potato cylinder which was put in solution B.

(3mks)

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c)i) State what would happen to red blood cells if they were placed in solution C. (1mk)

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ii) Explain your answer in (c)(i) above. (2mks)

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d) Name the process involved in uptake of mineral salts by plants from the soil. (1mk)

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4) a) Explain the term double fertilization as applied in plants. (3mks)

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b) State the role of each of the following hormones in male humans.

i) Follicle stimulating hormone. (1mk)

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ii) Testosterone (1mk)

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c) What is in vitro fertilization? (2mks)

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d) Name the causative agent of gonorrhea. (1mk)

………………………………………………………………………………………………………

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5. The diagram below shows part of gaseous exchange system in an insect. Study it and answer

the questions

that follow.

a) What are the structural adaptations of the parts labelled A and B to their functions? (2mks)

i) A:

………………………………………………………………………………………………………

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ii) B:

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b) Name the parts of the following animals that carry out the same function as part B above.

(2mks)

i)Man …………………………….…………………………………………………………

ii) Tilapia fish………………………….……………………………………………………..

c) Name the structures used for gaseous exchange in plants growing in water logged soils. (1mk)

………………………………………………………………………………………………………

………………………………………………………………………………………………………

A

Muscle

fibres

B

Spiracle

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d)i) Give two reasons why accumulation of lactic acid during vigorous exercise leads to an

increase in heartbeat. (2mks)

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ii) In what form is oxygen transported from lungs to the tissues? (1mk)

………………………………………………………………………………………………………

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Answer question 6 (compulsory) and either question 7 or 8 in the spaces provided after

question 8.

6. During germination and growth of a cereal, the dry weight of the endosperm, the embryo and

total dry

weight were determined at two day intervals. The results are shown in the table below.

Time after planting (Days) Dry weight of endosperm (mg) Dry weight of embryo (mg) Total dry weight (mg)

0 43 2 45

2 40 2 42

4 33 7 40

6 20 17 37

8 10 25 35

10 6 33 39

a)On the same axes, draw graphs of dry weight of endosperm, embryo and the total dry weight


b) What was the total dry weight on day 5? (1mk)

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c) Account for:

i) Decrease in dry weight of endosperm from day 0 to day 10. (2mks)

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ii) Increase in dry weight of embryo from day 0 to day 10. (2mks)

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iii) Decrease in total dry weight from day 0 to day 8. (1mk)

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……................................................................................................................................ ....................

iv) Increase in dry weight after day 8. (1mk)

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d) State two factors within the seed and two outside the seed that cause dormancy.

i) Factors within the seed. (2mks)

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ii) Factors outside the seed. (2mks)

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e) Give two characteristics of meristematic cells. (2mks)

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7. Describe how a mammalian heart is adapted for its function. (20mks)

8. a) Describe how xerophytes are adapted to living in their habitat. (10mks)

b) Explain how an upright position is maintained in herbaceous plants. (10mks)

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PROJECTION NO. 14

Name: ………………………………………………… Index No: ……………………..………….

School: …………………………………….......... Candidate’s Signature:……………………………..

Date:……………….…………….. ………

231/2

BIOLOGY

Paper 2

Theory

Time: 2 Hour







question 8.


SECTION QUESTION MAXIMUM SCORE CANDIDATES SCORE

A 1

2

3

4

5

8

8

8

8

8

B 6

7 or

8

20

20

20

TOTAL SCORE 80

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Answer all questions in this section.

1. The diagram below shows a specialized cell from a human being.

(a) Identify the cell. (1mk)

…………………………………………………………………………………………………………………….….........................

………………………………………………………………………………………………………………………………………….…..

(b) Name the parts labelled A,B, and C. (3mks)

A:……………………………………………………………………………………………….

B: ……………………………………………………………………………………………….

C: ……………………………………………………………………………………………….

(c) State the functions of the part labeled D. (1mk)

………………………………………………………………………………………………………………………………………….

………………………………………………………………………………………………………………………………………….

C

D

B

A

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(c) A student observed cells under a microscope and counted six (6) cells a cross the diameter of

view. The diameter of field of view was found to be 1.25mm. Calculate the length of one of

of the cells observed. ( Answer in micrometer). (3mks)

2. A group of students set up an experiment to investigate a certain physiological process. The set up

was as shown in the diagram below.

(a) What physiological process was being investigated? (1mk)

…………………………………………………………………………………............................................................

…………………………………………………………………………………………………………………………………………..

(b) (i) State two major observation that was made after some time. (2mks)

……………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………….

(ii) Account for the above observation in b (i) above. (4mks)

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Distilled water

Peeled Irish potato

Petri - dish

Concentrated salt solution

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(c) State the significance of the biological process involved in the experiment. (1mk)

……………………………………………………………………………………………………………………………………………….

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3. The diagram below represents a maize seedling.

(a) Name the parts labeled P and Q. (2mks)

P: ………………………………………………………………………………………………

Q: ……………………………………………………………………………………………….

(b) State the function of the part labeled R. (1mk)

……………………………………………………………………………………………………………………………………….…..

………………………………………………………………………………………………………………………….………………….

(c) Give three adaptations of the structure labeled S to its functions. (3mrks)

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(d) What is the role of air in germination of the above seedlings? (2mks)

…………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………….……………………………………………….

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P

R

Q

S

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4. The diagram below represents female reproductive system;

(a) Name the part labelled; A ,B ,C and D. (4mks)

A: ................................................................................................................................................

B: .................................................................................................................................................

C: ................................................................................................................................................

D: ................................................................................................................................................

(b) State two functions of structure A. (2mks)

......................................................................................................................................................

......................................................................................................................................................

(c) How is part C adapted to its functions? (1mk)

.....................................................................................................................................................

.....................................................................................................................................................

(d) Of what significance is part E to reproduction? (1mk)

....................................................................................................................................................

....................................................................................................................................................

B

C

D

E

F

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5. (a) What is mutation? (2mks)

......................................................................................................................................................

......................................................................................................................................................

(b) Explain why certain bacteria and other pathogens become resistance to drugs after some time.

(2mks)

.....................................................................................................................................................

.....................................................................................................................................................

………………………………………………………………………………………………………………………………………………..

(c) Work out a cross between a Haemophiliac man married to a carrier woman for Haemophilia.

Use letter h to represent genes. (3mks)

(d) State the phenotypic ratio of the children. (1mk)

......................................................................................................................................................

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SECTION B(40 MARKS)

Answer 6 Compulsory and Either Questions 7 and 8

6. A group of students carried out a study of the population growth of flour weevils. They put 16

grams of maize flour into two equal boxes K and L respective . They then introduced equal

numbers of weevils into the boxes. The boxes were kept under similar environmental conditions.

The weevils were counted at intervals and the results recorded in the table below.

No. of days after introduction of weevils Approximate No. of weevils present.

K L

0 20 20

5 20 20

40 200 300

60 550 800

80 560 1300

100 650 1750

120 640 1750

135 650 1740

150 645 1748

(a) Using a suitable scale ,draw two graphs on the same axes from the results in the table.

Plot approximate number of weevils present on the Y – axis( Use graph paper provided)

(8mks)

(b) What were the approximate number of weevils present in the two boxes on the 70th day.

(2mks)

Number in K: ...........................................................................................................................

Number in L:..............................................................................................................................

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(c) (i) On what day was the population of weevils in K 580. (1mk)

..................................................................................................................................................................

…………………………………………………………………………………………………………………………………………………………….

(ii) Between which days was the population difference greatest . (1mk)

.....................................................................................................................................................

………………………………………………………………………………………………………………………………………………

(d) Account for the shape of graph L between day 5 and day 100. (4 mks)

.........................................................................................................................................

.........................................................................................................................................

.........................................................................................................................................

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………………………………………………………………………………………………………………….………………….

……………………………………………………………………………………………………………………………………..

(e) State factors that would make the human species assume the graph curve above in K.(4mks)

..................................................................................................................................................................

..................................................................................................................................................................

…………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………………………

7. (a) Describe the mechanism of inhalation in man. (10mks)

(b) Using photosynthesis theory explain the mechanics of opening of stomata. (10mks)

8. Explain structure and functions of the human eye. (20mks)

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PROJECTION NO. 15

Name:……………………………………………………... Index No. ……………………………………………….…………………

School:……………………………………………………. Candidate’s Signature……………………………..……

Date: ………………………………………...

231/2

BIOLOGY

PAPER 2

(THEORY)

TIME: 2 HOURS







question 8.



A 1

2

3

4

5

8

8

8

7

4

B 6

7 or

8

9

5

20

20

20

TOTAL SCORE 80

of 744


1. State the functions of the following

(a) (i) Nerve cells (2mks)

………………………………………………………………………………………………….…………………………………………………………

…………………………………………………………………………………………………………………………………………………………….

(ii) Plasma (2mks)

…………………………………………………………………………………………………………………………………………………….………

……………………………………………………………………………………………………………………………………………………………

(b) Give the functions of the following organ systems

(i) Excretory system (2mks)

……………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………………

(ii) Endocrine system (2mks)

……………………………………………………………………………………………………………………………………………..……………

…………………………………………………………………………………………………………………………………………………………..

2. (a) Explain how the characteristics of the red blood cells adapt it to its functions (4mks)

……………………………………………………………………………………………………………….……………………………………………

……………………………………………………………………………………………………………………….……………………………………

…………………………………………………………………………………………………………………………….………………………………

……………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………….

(b) Explain the process of blood clotting (4mks)

………………………………………………………………………………………………………………….………………………………………

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3. (a) Name two sites where gaseous exchange takes place in an aquatic plant (2mks)

…………………………………………………………………………………..………………………………………………………………………

………………………………………………………………………………………..…………………………………………………………………

…………………………………………………………………………………………………………………………………………………………..

(b) The diagram below represents the gills of a bony fish. Study it and answer the questions that

follow

(i) Name the parts labeled A,B and C (3mks)

……………………………………………………………………………………………………………………………………………………..……

……………………………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………….………………………

…………………………………………………………………………………………………………………………………………………………….

(ii) State the functions of the part labelled A (2mks)

……………………………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………….……………………..

…………………………………………………………………………………………………………………………………………………………….

(iii) Explain how the part labelled C is adapted to perform its function (2mks)

……………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………..

A

B

C

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(c) Explain why the red blood cells are biconcave and lack a nucleus (1mk)

………………………………………………………………………………………………………………………………………….………………

…………………………………………………………………………………………………………………………………………..………………

…………………………………………………………………………………………………………………………………………………………..

4. In an experiment a variety of garden peas having a smooth seed coat was crossed with a variety with

wrinkled seed coat. All the seeds obtained in F1 generation had smooth seed coat. The F1 generation

selfed. The total number is F2 generation was 7324.

(a) Work out the total number of wrinkled seeds in the F2 generation (2mks)

(b) Give an explanation to the absence of plants with smooth seedcoat in the F1 generation (1mk)

…………………………………………………………………………………………………………………….……………………………………

……………………………………………………………………………………………………………………………………………….…………

(c) The following diagrams represents

Name the types of chromosomal mutations, X and Y (2mks)

………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………..

………………………………………………………………………………………………………………………………………………………

I II

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(d) Other than the above types of chromosomal mutations, name three other types of chromosomal

mutations (3mks)

……………………………………………………………………………………………………………………………………………….

………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………….

………………………………………………………………………………………………………………………………………………

5. (a) Explain the role of enzymes in living cells (1mk)

…………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………..

(b) The graph below shows the effects of temperature on the rate of reaction of the enzymes salivary

amylase

(i) Account for the changes in the curve between C and D (1mk)

……………………………………………………………………………………………………………………………………………………….……

…………………………………………………………………….………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………………………….

(ii) What does the dotted line represent? (1mk)

………………………………………………………………………………………………………………….…………………………………………

………………………………………………………………………………………………………………………………….…………………………

Temperature (oC)

10 20 20 40 50 60

Rat

e o

f re

spir

atio

n

P

C

D

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(c) Explain how the following factors affect the rate of enzyme activity

(i) Temperature (2mks)

……………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………………

(ii) Substrate concentration (2mks)

……………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………………

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SECTION B (40MKS)

Answer question six and either 7 or 8

6. In an experiment to investigate the effects of light intensity on the rate of photosynthesis, a shoot of

elodea (water weed) was used. The shoot was immersed in 2% sodium hydrogen carbonate solution

maintained at 15oC in an apparatus which allowed for collection of a gas evolved from the shoot. The

gas given off was collected for five minutes at each light intensity and its volume recorded as shown

below.

Light intensity

(arbitrary

units)

1 2 4 7 12 18 26 37 46

Gas evolved

(cm3 per 5

min)

0.45 0.70 0.95 1.40 1.75 1.82 1.90 1.90 1.90

(a) Using the data given in the table plot a suitable graph of gas evolved against light intensity (6mks)

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(b) Account for the rate of gas evolved

(i) 1 and 18 arbitrary units (3mks)

…………………………………………………………………………………………………………………….………………………………………

……………………………………………………………………………………………………………….……………………………………………

…………………………………………………………………………………………………………………….………………………………………

…………………………………………………………………………………………………………………………………………………………….

(ii) 26-46 arbitrary units (2mks)

……………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………….…………………

(c) Explain why a green leaf is normally tested for the presence of starch instead of glucose (2mks)

…………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………….

(d) How is the dry mass of a leaf determined (3mks)

………………………………………………………………………………………………………………………………………….…………………

…………………………………………………………………………………………………………………………….………………………………

………………………………………………………………………………………………………………………………….…………………………

……………………………………………………………………………………………………………………………………………………………

(e) Describe how the chloroplast is adapted to its functions (4mks)

……………………………………………………………………………………………………………………………………………………….……

…………………………………………………………………………………………………………………………………………………….………

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7. Discuss the various evidences which show that organic evolution has taken place (20 Marks)

8. Discuss the adaptations of the reproductive system of a male mammal to its function (20 Marks)

………………………………………………………………………………………………………………………………..…………………………

………………………………………………………………………………………………………………………….…………………………………

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PROJECTION NO. 16

NAME: ……………………………………………………………… INDEX NO: ……………………

SCHOOL: ……………………………………………..…………….. DATE: ………………….………

CANDIDATE’S SIGN: …………………………..………………

231/2

BIOLOGY

PAPER 2

TIME: 2 HOURS


• Write your name , school and index number in the spaces provided above.





question 8.



A 1

2

3

4

5

8

8

8

8

8

B 6

7 or

8

20

20

20

TOTAL SCORE 80

of 744


1. (a) State the role of the following parts of a light microscope. (2mks)

(i)Diaphragm

……………………………..…………………………………………………………………………….………………………………………………

……………………………………………………………………………………………………………………………………………………………

ii) Revolving nosepiece

……………………………….………………………………………………………………………………………………..……………………..

…………………………………………………………………………………………………………………………………………………………

(b) During preparation of temporary slides, the following procedures are carried out, state the

importance of each.

i) Staining (2mks)

……………………………….………………………………………………………….……………………………………………………………

………………………………………………………………………………………………………………………………………………………….

ii) Cutting very thin sections

……………………………….………………………………………………………………………………………………………………………..

…………………………………………………………………………………………………………………………………………………………

(c) Name the cell organelle that: (2mks)

i) Forms secretory vesicles

……………………………….………………………………………………………………..………………………………………………………

…………………………………………………………………………………………………………………………………………………………

ii) forms site of protein synthesis

………………………….…………………………………….……………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………

(d) Name the tissue that carry out the following functions in plants: (2mks)

i) Filling the spaces between other tissues.

………………………….……..………………………….…………………………………………………………..………………………………

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ii) Manufacture of food substances.

…………………………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………………………..

2. (a) Describe the following chromosomal mutations. (2mks)

(i) Inversion

……………………………….………………………………………………………………….…………………………………..…………………

…..……………………………….………………………………………………………………………………………………….……………………

(ii) Deletion.

……………………………….………………………………………………………………………………………..…………………………………

……………………………….……………………………………………………………………………………………………………………………

(b) In humans, the disease phenylketonuria is inherited through a recessive gene. A phenotypically

normal couple produced one normal child and one phenylketonuric child.

(i) Using a symbol A for normal gene and a for phenylketonuric gene, write down the

genotypes of the parents. (2mks)

……………………………….…………………………………………………………………………………………………………………………

……………………………….………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………

(ii) Work out the possible genotype of the normal child. (3mks)

(c) What is meant by genetic engineering? (1mk)

…………………………………………………………………………………………………………………………………………………….…

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3. The diagram below shows the structure of a flower.

(a)To what family does the flower belong? (1mk)

……………………………………………………………………………………………………………………………………………………….

………………………………………………………………………………………………………………………………….……………………

(b) (i) Suggest the agent of pollination of the flower. (1mk)

……………………………………………………………………………………………………………….………………………………………

…………………………………………………………………………………………………………….…………………………………………

ii) Give reasons for your answer in (b) (i) above. (2mks)

………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………

(c) Name the parts of the flower that develops into each of the following (2mks)

(i) Seed coat

…………………………………………………………………………….…………………………………………………………………………

………………………………………………………………………………………………………………………………………………………..

(ii) seed

……………………………………………………………………………………………………………………………………………………..

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(d) Pregnancy will continue normally even if the ovaries of an expectant mother are removed after 4

months. Explain. (2mks)

………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………….………………………………………………

4. (a) Distinguish between single circulatory and double circulatory system. (2mks)

……………………………………………………………………………………….………………………………………………………………

……………………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………………….

(b)A person of blood group O requires a transfusion. Name the blood group (s) of the possible donor.

(1mk)

………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………

(c) The diagram shows the exchange site between circulatory system and body cells.

(i) Name the blood cells labelled B. (1mk)

………………………………………………………………………………………………………………………………………….………

………………………………………………………………………………………………………………………………………………….

(ii) State the difference between blood and tissue fluid. (2mks)

…………………………………………………………………………………..………………………………………………………………

………………………………………………………………………………………….…………………………………………………………

Flow of blood

Body cells Tissue fluid

B

of 744


(d) State two environmental factors that cause a decrease in rate of transpiration in leaves. (2mks)

………………………………………………………………………………………………………………………….…………………………

…………………………………………………………………………………………………………………………………………….………

…………………………………………………………………………………………………………………………………………………….

5. (a) What are the analogous structures as used in evolution? (1mk)

…………………………………………………………………………………………………………………………………………….………

……………………………………………………………………………………………………………………………………..………………

……………………………………………………………………………………………………………………………………………………..

(b) How do disease causing micro-organisms become resistant to drugs. (3mks)

……………………………………………………………………………………………………………………………………………….………

……………………………………………………………………………………………………….………………………………………………

……………………………………………………………………………………………………….………………………………………………

…………………………………………………………………………………………………………………………………………………………

(c)The diagram below represents a bone of a mammal.

(i) Identify the bone. (1mk)

……………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………..

(ii) Name the bone that articulates at the point labelled F. (1mk)

……………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………

(iii) Explain two adaptations of the bone identified in (i) above. (2mks)

………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………

F

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………………………………………………………………………………………………………………………………………….…………

……………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………


Answer all question 6 (compulsory) and either question 7 and 8 in the spaces provided after question 8.

6. (a) An experiment was carried out to investigate the population of a certain micro-organism.

Two Petri-dishes were used. Into the petridish labelled M, 60cm3 of a culture medium was

placed while 30cm3 of the same culture medium was placed in Petri-dish labelled N equal

numbers of micro organisms were introduced in both Petri dishes. The set ups were then

incubated at 350C. The number of micro-organisms in each was determined at irregular

intervals for a period of 60 hours. The results were as shows in the table below.

Relative number of microorganisms

M 40 40

180

280 1200

1720

1600 1840 1560 600

N 40 40 120 200 680 560 560 600 600 400

Time in hours 0 5 10 15 23 30 35 42 45 60

(i) On the same axes, draw the graphs of relative number of microorganisms against time on the grid

provided. (7mks)

(ii) After how many hours was the difference between the two populations greatest? (1mk)

……………………………………………………………………………………………………………………………………………………..

……………………………………………………………………………………………………………………………………………………

(iii) Work out difference between the two populations at 50 hours. (2mks)

…………………………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………………………

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(iv) With a reason state the effect on the population of microorganisms in petridish M if the

temperature was raised to 600C after 20hours. (2mks)

…………………………………………………………………………………………………………………………………………..……

…………………………………………………………………………………………………………………………………………………

(v) Account for the shape of the curve for population in petridish N between 46 hours and 59 hours.

(3mks)

……………………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………………….

………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………

(b) Explain how the osmotic pressure of the mammalian blood is maintained constant. (5mks)

………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………………….

………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………….

7. Explain how the mammalian eye is adapted to its functions (20mks)

8. Explain how abiotic factors affect plants. (20mks)

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of 744


PROJECTION NO. 17

NAME: ……………………………………………………….… INDEX NO……………………..…

SCHOOL………………………………………………….…………… DATE: ………..…………….…………

CANDIDATE’S SIGNATURE…………………………………

231/2

BIOLOGY

PAPER 2 (Theory)

Time: Hours






• In section B, answer question 6(compulsory) and either question 7 or 8 in the spaces provided

after question 8.



A 1

2

3

4

5

8

8

8

8

8

B 6

7 or

8

20

20

20

TOTAL SCORE 80

This paper consists of 8 printed pages. Candidates should check to ascertain that all papers are

printed as indicated and that no questions are missing

of 744



Answer all the questions in this section in the spaces provided.

1. A cross between a red flowered plants produced plants with pink flowers.

Using R to represent the gene for red colour, and W for white colour,

(a) What were the parental genotypes (1mark)

……………………………………………………………………………………………………………………………………..

……………………………………………………………………………………………………………………………………..

(b) Work out a cross between F1 plants. (4marks)

(c) Give the:

(i) Phenotypic ratio of F2 plants (1mark)

………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………

(ii) Genotypic ratio of F2 plants (1mark)

………………………………………………………………………………………………………………………………………..

…………………………………………………………………………………………………………………………………………

(d)Name a characteristic in humans which is controlled by multiple alleles. (1mark)

…………………………………………………………………………………………………………………………………………

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2. In an experiment to investigate an aspect of digestion, two test tubes P and Q were set

up as shown in the diagram below.

The test tubes were left in the water bath for 30 minutes. The content of

each test tube was then tested for starch using iodine solution.

(a) What was the aim of the experiment? (1mark)

…………………………………………………………………………………………………………………………..

………………………………………………………………………………………………………………………….

(b) What results were expected in test tube P and Q. (2marks)

P…………………………………………………………………………………………….

Q……………………………………………………………………………………………

(c) Account for the results you have given in (b) above test tube P and Q (2marks)

…………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………..

………………………………………………………………………………………………………………………………………..

(d) Why was the set up left at 37oC for 30 minutes? (1mark)

………………………………………………………………………………………………………………………………………….

………………………………………………………………………………………………………………………………………..

Set up P Set up Q

Starch + Saliva

Water bath maintained

at 37oC

Starch + boiled saliva

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(e) Name the carbohydrate stored in (2marks)

(i) Mammalian liver

…………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………….

(ii) Potato tuber

………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………

3. The diagram below represents the female reproductive system.

(a) Name the structures labelled A and C (2marks)

…………………………………………………………………………………………………………………………………..

…………………………………………………………………………………………………………………………………..

…………………………………………………………………………………………………………………………………..

(b) State the conditions that results if implantation occurs at point labelled D. (1mark)

………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………….

B

A C

D

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(c) Name the hormone secreted by the part labelled A and for each give one function.

(4marks)

……………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………..

………………………………………………………………………………………………………………………………….

………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………..

(d) What role does part labelled B play during pregnancy? (1mark)

…………………………………………………………………………….............................................................

…………………………………………………………………………………………………………………………………………


(a) What type of evolution is illustrated by the limbs? (1mark)

…………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………

Grasping

twigs. etc

(weaver)

Waders

(water bird)

Graspin

g twigs.

etc

(weaver

)

Heavy-

clawed

(eagle)

Webbed

(ducks)

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(b) What does the origin of the limbs suggest about the ancestry of these

animals? (1mark)

………………………………………………………………………………………………………………………………….…

……………………………………………………………………………………………………………………………………..

(c) (i) What are the vestigial structures?

…………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………….

(ii) State any example of vestigial structures in human. (1mark)

……………………………………………………………………………………………………………………………………..

………………………………………………………………………………………………………………………….…………….

(d) (i) What is natural selection? (1mark)

………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………

(ii) Give one example of natural selection in action (1mark)

……………………………………………………………………………………………………………………..…………………

……………………………………………………………………………………………………………….……………………….

(e) Explain comparative serology as an evidence of evolution. (2marks)

………………………………………………………………………………………………………….……………………………

…………………………………………………………………………………………………………………..………………….

………………………………………………………………………………………………………………………………………..

5. (a) What is blood transfusion ? (1mark)

…………………………………………………………………………………………………………………………..…………….

…………………………………………………………………………………………………………………………………………

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(b) State three precautions to be observed before transfusing blood. (3marks)

…………………………………………………………………………………………………………………….………………….

……………………………………………………………………….………………………………………………………………..

………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………..

(c) State the advantage and disadvantage of blood group O. (2marks)

Advantage

…………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………….

Disadvantage

…………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………….

(d) (i) What is a universal recipient? (1mark)

……………………………………………………………………………………………………………………………………….

………………………………………………………………………………………………………………………………………..

(ii) State the blood group of universal recipient. (1mark)

…………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………

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Answer any 6 (COMPULSORY) in the spaces provided and either question 7 or 8 in the

spaces provided after question 8.

6. Two persons A and B drunk volumes of concentrated solutions of glucose. The amounts

of glucose in their blood was determined at intervals. The results are shown in the table below.

Time in minutes Glucose level in blood (mg/100cm3)

A B

0 87 84

15 112 123

30 139 170

45 116 188

60 100 208

90 95 202

120 92 144

150 88 123

(a) On the grid provided, plot graphs of glucose level in blood against time on the

same axes. (7marks)

(b) What was the concentration of glucose in the blood of person A and B at the 20th

minute? (2 marks)

A…………………………………………………………………………….

B…………………………………………………………………………..

(c)Suggest why glucose level in person A stopped rising after 30 minutes

while it continued to rise in person B. (2marks)

…………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………..

……………………………………………………………………………………………………………………………………….

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(c) Account for the decrease in glucose level of person A after 30 minutes

and person B after 60 minutes. (4marks)

A………………………………………………………………........................................................

B………………………………………………………………........................................................

(e)Name the compound that stores energy released during oxidation of

glucose. (1mark)

……………………………………………………………………………………………………………………….

………………………………………………………………………………………………………………………

(f) Explain what happens to the excess amino acids in the body. (4marks)

…………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………..

………………………………………………………………………………………………………………………..

7. (a) Name and state the functions of the cellular components of mammalian

blood. (7marks)

(b)What are the functions of the blood plasma in mammals? (13marks)

8. Explain how a bony fish is adapted for movement in its habitat. (20marks)

………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………

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………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………..

………………………………………………………………………………………………………………………..…………………………

………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………….

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PROJECTION NO. 18

NAME …………………………………………………………… INDEX NO……………..……………..………………………….

SCHOOL ………………………………………………………… CANDIDATE’S SIGNATURE………………………………..

. DATE…………………………………………………………..

231/2

BIOLOGY

PAPER 2

(THEORY)

TIME: 2 HOURS



• This paper consist of TWO sections; A and B.

• Answer all the questions in the section A in the spaces provided.

• In section B answer Question 6 (compulsory) and either question 7 or 8 in the space provided after question 8.

• Check to ascertain that all pages are printed and that no questions are missing.


Section Question Maximum

Score

Candidates

Score

A

1 8

2 8

3 8

4 8

5 8

B 6 20

7 20

8 20

Total Score 80

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1. Examine the diagram below and use it to answer the questions that follow.

(a) Name the parts labeled. (3mks)

B __________________________________________________________________________

C __________________________________________________________________________

D __________________________________________________________________________

(b) What is the substance which makes up part labeled A? (1mk)

____________________________________________________________________________

_____________________________________________________________________________

(c) Name the process by which mineral salts move into structure B. (1mk)

_______________________________________________________________________________

_______________________________________________________________________________

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(d) Explain what happens when a red blood cell is put in distilled water. (3mks)

____________________________________________________________________________

____________________________________________________________________________

____________________________________________________________________________

____________________________________________________________________________

2. The figure below is a pedigree showing the inheritance of colourblindness, a disease transmitted

through a recessive gene located on the X-chromosome.

(a) Using the symbol N for normal gene and n for colourblind gene, write down the genotypes

of parents 1 and 2. (2mks)

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

(b) Work out the possible genotypes of the children 3, 4 and 5. (4mks)

1 2

3 4 5 6

7 8 9

Normal male

Colourblind male

Normal female

male Colourblind male

KEY

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(c) The diagrams below illustrate some chromosome mutations.

A

B

C

Identify the mutations. (3mks)

Meiosis

X X

A

B

C

D

E

F

V

U

W

X

E

F

V

U

W

X

A

C

B

D

A

B

C

D

B

C

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A __________________________________________________________________________

B __________________________________________________________________________

C __________________________________________________________________________

3. The diagram below shows structures of the bat wing and human arm.

(a) These structures are thought to have same ancestral origin. State one structural similarity and one adaptational difference between the two.

(i) Structural similarity. (1mk)

____________________________________________________________________

_____________________________________________________________________

(ii) Adaptational difference. (2mks)

____________________________________________________________________

____________________________________________________________________

____________________________________________________________________

____________________________________________________________________

(b) Give two other examples of structures in nature that show the type of evolution as in

Wing membrane

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(a) above. (2mks)

___________________________________________________________________________

___________________________________________________________________________

____________________________________________________________________________

(c) Distinguish between the terms ‘chemical evolution’ and ‘organic evolution’. (2mks)

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

(d) What is the study of fossils called? (1mk)

___________________________________________________________________________

___________________________________________________________________________

4. The diagram below represents some hormones, their sources and functions in a mammal.

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(a) Identify the gland described as master gland. (1mk)

___________________________________________________________________________

(b) Name the hormones:- (4mks)

II __________________________________________________________________________

III _________________________________________________________________________

V __________________________________________________________________________

VI _________________________________________________________________________

(c) Describe the consequences of deficiency of hormone II in man. (2mks)

Master gland

I III V

Stimulates tests Stimulates

growth of follicles Stimulates

in ovary development

of corpus

luteum

II

Stimulates

spermatogenesis IV

Stimulates VI

development of Stimulates

secondary sexual development

characteristics of uterine wall

Female

Male

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____________________________________________________________________________

____________________________________________________________________________

____________________________________________________________________________

____________________________________________________________________________

(d) Other than stimulate development of uterine wall, suggest two other functions of hormone

VI. (2mks)

____________________________________________________________________________

____________________________________________________________________________

____________________________________________________________________________

____________________________________________________________________________

5. Ascaris lumbricoides is an endoparasite.

(a) Name the genus to which it belongs. (1mk)

____________________________________________________________________________

_____________________________________________________________________________

(b) State the habitat of the organism. (1mk)

____________________________________________________________________________

____________________________________________________________________________

(c) State three ways in which the organism is adapted to living in its habitat. (3mks)

___________________________________________________________________________

____________________________________________________________________________

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____________________________________________________________________________

(d) Mention three ways of preventing spread of the parasite. (3mks)

____________________________________________________________________________

____________________________________________________________________________

____________________________________________________________________________


Answer question 6 (compulsory) and EITHER question 7 or 8 in the spaces provided after

question 8.

6. The table below shows how the quantities of sweat and urine vary with external temperature.

External temperature C Urine cm³/hr Sweat cm³/hr

0 100 5

5 90 6

10 80 10

15 70 20

20 60 30

25 50 60

30 40 120

35 30 200

(a) On the same graph, plot the quantities of urine and sweat produced against the external temperature. (7mks)

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(b) At what temperature are the amounts of sweat and urine produced equal? (1mk)

__________________________________________________________________________

__________________________________________________________________________

(c) What happens to the amount of sweat produced as the temperature rises? Explain the

observation. (3mks)

__________________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

(d) Explain the observation made on the amount of urine produced as the temperature

increases. (3mks)

__________________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

(e) How is the skin adapted for temperature regulation? (6mks)

__________________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

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__________________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

7. Describe the structural adaptations of the mammalian heart to its function. (20mks)

8. Describe how water moves from the soil to the leaves in a tree. (20mks)

_______________________________________________________________________________________

_______________________________________________________________________________________

_______________________________________________________________________________________

_______________________________________________________________________________________

_______________________________________________________________________________________

_______________________________________________________________________________________

_______________________________________________________________________________________

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_______________________________________________________________________________________

_______________________________________________________________________________________

_______________________________________________________________________________________

_______________________________________________________________________________________

_______________________________________________________________________________________

_______________________________________________________________________________________

_______________________________________________________________________________________

_______________________________________________________________________________________

_______________________________________________________________________________________

_______________________________________________________________________________________

_______________________________________________________________________________________

_______________________________________________________________________________________

_______________________________________________________________________________________

_______________________________________________________________________________________

_______________________________________________________________________________________

_______________________________________________________________________________________

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PROJECTION NO. 19

NAME: …………………………………………. INDEX NO: ……………………………….

SIGNATURE: …………………………………. DATE : ……………………………………

231/2

BIOLOGY

PAPER 2

(THEORY)

TIME: 2 HOURS

INSTRUCTIONS TO CANDIDATES:

(a) Write your Name and Index Number in the spaces provided.

(b) Sign and write the Date of examination in the spaces provided.

(c) This paper consists of TWO sections A and B.

(d) Answer all questions in section A in the spaces provided.

(e) In section B, answer question 6 (compulsory) and either question 7 or 8 in the spaces provided.


SECTION QUESTION MAX. SCORE CANDIDATE SCORE

A

1 8

2 8

3 8

4 8

5 8

B

6 20

7 20

8 20

TOTAL 80

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1. The diagram below shows surface view of a human brain.

(a) Name the part labeled B and C. (2mks)

B:…………………………………………………………………………………………

C:…………………………………………………………………………………………

(b) State three functions of the part labeled A. (3mks)

……………………………………………………………………………………………

……………………………………………………………………………………………

……………………………………………………………………………………………

…………………………………………………………………………………………..

(c) State what would happen if the part labeled B was damaged. (2mks)

……………………………………………………………………………………………

……………………………………………………………………………………………

……………………………………………………………………………………………

…………………………………………………………………………………………..

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2. The diagram below represents part of phloem tissue.

(a) Name the structures labeled R and S and the cell labeled T. (3mks)

R:…………………………………………………………………………………………

S:…………………………………………………………………………………………

Cell labeled T:…………………………………………………………………………..

(b) State the function of the structure labeled S. (1mk)

……………………………………………………………………………………………

(c) Explain why xylem is a mechanical tissue. (2mks)

……………………………………………………………………………………………

……………………………………………………………………………………………

(d) (i) State the effect of removal of the cell labeled T. (1mk)

……………………………………………………………………………………………

……………………………………………………………………………………………

(ii) Give a reason for your answer in (a) above. (1mk)

……………………………………………………………………………………………

…………………………………………………………………………………………….

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3. (a) Name two disorders in human caused by gene mutation. (2mks)

…………………………………………………………………………………………………

…………………………………………………………………………………………………..

(b) Describe the following chromosomal mutations:

(i) Inversion (2mks)

………………………………………………………………………………………………

……………………………………………………………………………………………..

(ii) Translocation (2mks)

………………………………………………………………………………………………

……………………………………………………………………………………………….

(c) In mice the allele for black fur is dominant to the allele for brown fur. What

percentage of offspring would have brown fur form a cross between heterozygous

black mice? Show working. Use letter B to represent the allele for black colour.

(4mks)


(a) (i) Which part marked a, b, c and d, when defective after implantation may lead

to abortion. (1mk)

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……………………………………………………………………………………………

…………………………………………………………………………………………..

(ii) Give a reason for your answer. (1mk)

……………………………………………………………………………………………

……………………………………………………………………………………………

…………………………………………………………………………………………….

(b) The part labeled b can be removed after 4 months of pregnancy without

interfering with the pregnancy. Explain. (2mks)

……………………………………………………………………………………………

……………………………………………………………………………………………

……………………………………………………………………………………………

…………………………………………………………………………………………….

(c) Under each of the following, state the name of the causative agent.

(i) Syphillis (1mk)

……………………………………………………………………………………….

(ii) Gonorrhea (1mk)

……………………………………………………………………………………….

(iii) AIDS

(1mk)

………………………………………………………………………………………..

(d) State two disadvantages of external fertilization. (2mks)

……………………………………………………………………………………………

…………………………………………………………………………………………….

5. Study the figure below and answer the questions that follow.

Semipermeable Membrane Solution A Solution B Sugar Molecule (a) Which solution has higher concentration of free water molecules? (1mk)

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………………………………………………………………………………………………

……………………………………………………………………………………………...

(b) Which solution is more concentrated? (1mk)

………………………………………………………………………………………………

(c) In which direction will osmosis take place? Indicate using an arrow. (1mk)

(d) What does semi-permeable membrane represent in an animal cell (1mk)

………………………………………………………………………………………………

………………………………………………………………………………………………

(e) Name two processes in living organisms that depend on osmosis. (2mks)

………………………………………………………………………………………………

………………………………………………………………………………………………

………………………………………………………………………………………………

SECTION B – 40 MARKS

Answer question 6 (Compulsory) and any other one question from this section.

6. During germination and growth of a cereal, the dry weight of endosperm, the embryo

and total dry weight were determined at two-day intervals. The results are shown in

the table below.

Time after planting Dry weight of endosperm

Dry weight of embryo (mg)

Total dry weight (mg)

0 43 2 45

2 40 2 42

4 33 7 40

6 20 17 37

8 10 25 35

10 6 33 39

(a) Using the same axes, draw graphs of dry weight of endosperm, embryo and the

total dry weight against time. (8mks)

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(b) What is the total dry weight on day 5? (1mk)

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………………………………………………………………………………………………

……………………………………………………………………………………………...

(c) Account for:

(i) Decrease in dry weight for endosperm from day 0 to 10. (2mks)

…………………………………………………………………………………………

…………………………………………………………………………………………

………………………………………………………………………………..

(ii) Increase in dry weight of embryo from day 0 to 10. (2mks)

…………………………………………………………………………………………

…………………………………………………………………………………………

…………………………………………………………………………………

(iii) Decrease in total dry weight from day 0 to day 8. (2mks)

…………………………………………………………………………………………

…………………………………………………………………………………………

………………………………………………………………………………….

(iv) Increase in total dry weight after day 8. (1mk)

…………………………………………………………………………………………

…………………………………………………………………………………………

…………………………………………………………………………………

(d) State one cause of dormancy: (2mks)

(i) Within a seed

………………………………………………………………………………………………

(ii) Outside the seed

………………………………………………………………………………………………

7. Explain the role of human skin in:

(a) Thermo regulation. (14mks)

(b) Protection (6mks)

8. Explain various ways in which fruits and seeds are adapted to dispersal. (20mks)

PROJECTION NO. 20

of 744


NAME……………..………………………………………… INDEX NO……...........………………..………

SCHOOL…………………………………………………… CANDIDATE’S SIGNATURE……………………..

DATE………..………………….

231/2

BIOLOGY

PAPER 2

(THEORY)

TIME: 2 HOURS



• This paper consist of TWO sections; A and B. • Answer all the questions in the section A in the spaces provided.


• Check to ascertain that all pages are printed and that no questions are missing. FOR EXAMINER’S USE ONLY


Score

Candidates

Score

A

1 8

2 8

3 8

4 8

5 8

B 6 20

7 20

8 20

Total Score 80


of 744



1. The graph below show the effect of temperature on an enzyme catalysed reaction.

(a) Account for the shape of the curve between. (i) A and B. (3 marks)

____________________________________________________________________

____________________________________________________________________

____________________________________________________________________

____________________________________________________________________

(ii) C and D. (2 marks)

____________________________________________________________________

______________________________________________________________________

______________________________________________________________________

•

• • X B C

A

D

Rate of

Reaction

Temperature

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______________________________________________________________________

(b) What does the point marked X represent? (1 mark)

____________________________________________________________________________

____________________________________________________________________________

____________________________________________________________________________

(c) Apart from temperature, state two other factors that affect the rate of enzyme controlled

reaction. (2 marks)

____________________________________________________________________________

____________________________________________________________________________

____________________________________________________________________________

2. Color blindness is a sex linked trait caused by a recessive gene on the X chromosome. Using the

symbol XC to represent the gene for normal colour vision and Xc to represent the gene for colour

blindness work out the following.

(a) The phenotype of children born to a normal man and carrier woman. (5 marks)

(b) What is the genotypic ratio of their children? (1 mark)

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(c) Define the term:

(i) Allelle. (1 mark)

______________________________________________________________________

______________________________________________________________________

______________________________________________________________________

(ii) Genetic engineering. (1 mark)

______________________________________________________________________

______________________________________________________________________

______________________________________________________________________

3. (a) State the functions of the following parts of the ear.

(i) Tymphanic membrane. (1 mark)

______________________________________________________________________

______________________________________________________________________

______________________________________________________________________

(ii) Eustachian tube. (1 mark)

______________________________________________________________________

______________________________________________________________________

______________________________________________________________________

(iii) Vestibular apparatus. (1 mark)

______________________________________________________________________

______________________________________________________________________

______________________________________________________________________

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(b) (i) Define tropic response. (1 mark)

______________________________________________________________________

______________________________________________________________________

______________________________________________________________________

(ii) What is the importance of tropic response? (1 mark)

______________________________________________________________________

______________________________________________________________________

______________________________________________________________________

(c) State one role of meninges. (1 mark)

______________________________________________________________________

______________________________________________________________________

4. The diagram below shows part of a longitudinal section of a young root.

(a) Name the parts labelled A, B, C and D. (4 marks)

A __________________________________________________________________________

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B __________________________________________________________________________

C __________________________________________________________________________

D __________________________________________________________________________

(b) State the function of the part labeled A. (1 mark)

__________________________________________________________________________

___________________________________________________________________________

____________________________________________________________________________

(c) How is the tissue labelled D adapted to it function. (3 marks)

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

5. The experiment below was set up to demonstrate a physiological process. Two tubes A and B made

of sheep’s bladder were filled with different liquids and placed in a basin containing a liquid.

After 20 minutes it was found that tube A felt hard and the liquid in it had increased.

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Tube B was soft and contained less liquid.

(a) Explain what took place in tube A. (2 marks)

____________________________________________________________________________

____________________________________________________________________________

____________________________________________________________________________

____________________________________________________________________________

Tube B. (2 marks)

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

(b) Identify the liquid hypertonic to the liquid in the basin. (1 mark)

___________________________________________________________________________

(c) What does the sheep’s bladder correspond to in a living organism. (1 mark)

___________________________________________________________________________

(d) What physiological process was being investigated in the above experiment? (1 mark)

___________________________________________________________________________

(e) What is the meaning of the term haemolysis. (1 mark)

___________________________________________________________________________

____________________________________________________________________________

___________________________________________________________________________

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6. You have been provided with the data below on the growth of mice population. The population

starts with two sexually mature mice, a male and a female. Every time they reproduce they

reproduce in litter of six (3 males and 3 females) at 7 weeks intervals. Assume that they take

14 weeks to sexually mature and produce. They only die of old age when they are 3 years old.

The following table shows population growth and litter production.

Time interval in weeks 0 7 14 21 28 35 42 49

Mice population 2 8 14 28 62 104 146 260

Litter population 0 6 6 24 24 42 42 114

(a) Using the same axis draw graphs of population of mice and litter against time. (8 marks)

(b) (i) How many times has the first litter of mice reproduced. (1 mark)

______________________________________________________________________

_______________________________________________________________________

(ii) How many times has the third litter of mice reproduced? (1 mark)

______________________________________________________________________

______________________________________________________________________

(c) State four factors that may have affected the population growth of mice. (4 marks)

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(d) Explain the shape of the litter curve. (4 marks)

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(e) How many pairs of mice reproduced between 14 - 21st weeks and 42 - 49 weeks?(2 marks)

(i) Between 14 – 21st weeks.

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(ii) Between 42 – 49 weeks.

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7. Describe how the structure of mammalian skin is adapted to its function. (20 marks)

8. Describe the role of hormones in human female menstrual cycle. (20 marks)

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PROJECTION NO. 21

NAME: …………………………………………. INDEX NO: ……………………………….

SIGNATURE: …………………………………. DATE : ……………………………………

231/2

BIOLOGY

PAPER 2

(THEORY)

TIME: 2 HOURS


(f) Write your Name and Index Number in the spaces provided.

(g) Sign and write the Date of examination in the spaces provided.

(h) This paper consists of TWO sections A and B.

(i) Answer all questions in section A in the spaces provided.

(j) In section B, answer question 6 (compulsory) and either question 7 or 8 in the spaces

provided.



A

1 8

2 8

3 8

4 8

5 8

B

6 20

7 20

8 20

TOTAL 80

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1. The diagram below shows how gaseous exchange occurs across the gills of a fish.

(a) From the diagram above, water and blood flow in opposite direction.

(i) Give the term used to describe this type of flow. (1mk)

…………………………………………………………………………………………

………………………………………………………………………………….…

(ii) Explain the significance of this type of flow. (2mks)

…………………………………………………………………………………………

…………………………………………………………………………………………

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(b) Name two organs in human beings that display the flow system named in (a) (i)

above. (2mks)

……………………………………………………………………………………………

…………………………………………………………………………………………….

(c) Explain why the gills of a fish are:

(i) Highly vascularised. (1mk)

………………………………………………………………………………………

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(ii) Thin walled (1mk)

……………………………………………………………………………………

…………………………………………………………………………………….

(iii) Moist (1mk)

………………………………………………………………………………………

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2. A pea plant with round seeds was crossed with a pea plant that had wrinkled seeds.

The gene for round seeds is dominant over that for wrinkled seeds.

Using letter R to represent the dominant gene state:

(a) The genotype of parents if plant with round seed was heterozygous. (2mks)

..……………………………………………………………………………………………

……………………………………………………………………………………………

………………………………………………………………………………………….

…………………………………………………………………………………………….

(b) The gametes produced by the round and wrinkled seed parents:-

Round seed parent (1mk)

…………………………………………………………………………………………….

Wrinkled seed parent. (1mk)

…………………………………………………………………………………………….

(c) The genotype and phenotype of F1 generation. Show your working.

. (3mks)

(d) What is a test-cross? (1mk)

……………………………………………………………………………………………

……………………………………………………………………………………………

3. A student set up an experiment to investigate a certain process. Study it and answer

the questions that follow. The cubes are of the same size and shape.

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(a) (i) Name the process being investigated. (1mk)

……………………………………………………………………………………………

(ii) What observations would be made after 40 minutes? (2mks)

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(b) Account for your observation. (4mks)

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(c) Suggest a control experiment for this experiment. (1mk)

……………………………………………………………………………………………

4. The diagram below represents a villus.

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(a) (i) State the roles of the following structures in the villus: (2mks)

Capillary:

……………………………………………………………………………………….…..

…………………………………………………………………………………………….

Lacteal:

……………………………………………………………………………………………

……………………………………………………………………………………………

(ii) The epithelial cells, one of which is shown enlarged on the figure have

microvilli on their exposed surface. Suggest an advantage of these microvilli

to the epithelial cells. (1mk)

………………………………………………………………………………………

………………………………………………………………………………………

(b) (i) Name the process by which the products of digestion, present in high

concentrations in the ileum, would pass into the capillaries. (1mk)

……………………………………………………………………………………………

……………………………………………………………………………………………

(ii) Describe how the capillaries are adapted to allow this process to happen

efficiently. (2mks)

……………………………………………………………………………………………

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(c) Some substances are absorbed into the capillaries by active uptake.

(iv) Explain why active uptake is sometimes necessary. (1mk)

……………………………………………………………………………………….

……………………………………………………………………………………….

(v) Suggest why active uptake stops when the epithelial cells of the ileum are

exposed to a respiratory poison. (1mk)

………………………………………………………………………………………

……………………………………………………………………………………….

5. The diagram below shows a cross section through the female part of a flower.

(f) Name the structures labeled W, X and Y. (3mks)

X:……………………………………………………………………………………………

Y:……………………………………………………………………………………………

Z:…………………………………………………………………………………………….

(g) State two functions of the pollen tube. (1mk)

………………………………………………………………………………………………

………………………………………………………………………………………………

(h) What happens to antipodal cells after fertilization? (1mk)

………………………………………………………………………………………………

…………………………………………………………………………………………

(i) What does semi-permeable membrane represent in an animal cell (1mk)

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(j) Name the structure labeled K and state their role. (2mks)

………………………………………………………………………………………………

………………………………………………………………………………………………

……………………………………………………………………………………………….

SECTION B

Answer question 6 (Compulsory) and any other one question from this section.

6. In an experiment, a plant was exposed to different light intensities and a range of

carbon (IV) oxide concentration in a green house. Rate of photosynthesis was then

determined using the product formed. The product was measured in mg-sec(s).

(e) Plot a graph of rate of photosynthesis against carbon (IV) oxide concentration.

(7mks)

(f) (i) At what interval of carbon (IV) oxide was the rate of photosynthesis

determined? (1mk)

………………………………………………………………………………………………

………………………………………………………………………………………………

(ii) The amount of carbon (IV) oxide in the atmosphere air is about 0.03%. What

was the rate of photosynthesis at this concentration in dim light? (1mk)

………………………………………………………………………………………………

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(g) Suggest the factors which was limiting the rate of photosynthesis between 0.12

and 0.20% carbon (IV) oxide in:

(i) Dim light. (2mks)

…………………………………………………………………………………………

…………………………………………………………………………………………

…………………………………………………………………………………

(ii) Bright light. (2mks)

…………………………………………………………………………………………

…………………………………………………………………………………………

…………………………………………………………………………………

(h) (i) Explain the advantages of the leaf being broad and flat. (2mks)

………………………………………………………………………………………………

………………………………………………………………………………………………

……………………………………………………………………………………………...

(ii) What is the fate of excess products of photosynthesis? (2mks)

………………………………………………………………………………………………

………………………………………………………………………………………………

……………………………………………………………………………………………..

(i) Describe how photosynthesis theory accounts for changes on stomata rhythm

during the day. (5mks)

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7. (a) Explain why plants lack elaborate excretory organs like those found in animals.

(3mks)

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(b) Name five methods of excretion in plants. (5mks)

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(c) State any six excretory products in plants and give economic uses. (12mks)

8. How is the human eye adapted to its function? (20mks)

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PROJECTION NO. 22

NAME: ……………………………………………….INDEX NUMBER: ……………………..

CLASS: ……………………………………….. ADM. NO. …………………………

BIOLOGY

PAPER 2

[THEORY]

TIME: 2 HRS

Instructions to candidates

1. Write your name, class and admission number in the spaces provided above.

2. Answer all the questions In section A in the spaces provided

3. In section B, answer question 6 [compulsory] and either question 7 or 8 in the spaces

provided after question 8

For examiners use only


A 1 8

2 6

3 10

4 8

5 8

B 6 20

7 or 8 20

Total Score 80

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Section A [40 marks]

1. [a] What is meant by the term sex linked genes? [1 mark]

……………………………………………………………………………………………………

……………………………………………………………………………………………………

[b] Name two sex linked traits in humans. [2 marks]

……………………………………………………………………………………………………

……………………………………………………………………………………………………

……………………………………………………………………………………………………

[c] In drosophila melanongaster , the inheritance of the eye colour is sex linked. The gene is

dominant. A cross was made between a heterozygous red eyed female and a white eyed

male. Work out the phenotypic ratio of F1 generation. [Use R to represent the gene for red

eye color.] [5 marks]

2. The diagram below represents a mature fruit of a certain plant.

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[a] State the agent for dispersal for the fruit. [1 mark]

……………………………………………………………………………………………………

……………………………………………………………………………………………………

[b] Give a reason for your answer in [a] above. [1 mark]

……………………………………………………………………………………………………

……………………………………………………………………………………………………

[c] State two characteristics of fruits and seeds dispersed by the agent you named in [a] above.

[1 mark]

……………………………………………………………………………………………………

……………………………………………………………………………………………………

……………………………………………………………………………………………………

[d] What are the advantages of fruit and seed dispersal? [2 marks]

……………………………………………………………………………………………………

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……………………………………………………………………………………………………

[e] State one importance of fruits in the survival of plants. [1 mark]

……………………………………………………………………………………………………

……………………………………………………………………………………………………

……………………………………………………………………………………………………

3. [a] What are vestigial structures? Give an example. [2 marks]

……………………………………………………………………………………………………

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[b] How do vestigial structures act as evidence that evolution has taken place? [1 mark]

……………………………………………………………………………………………………

……………………………………………………………………………………………………

[c] The peppered moth [biston betularia] exists in many parts of England. It normally rests on

barks of trees. It exists in two major forms; a normal or wild type which is speckled white and a

mutant variety which is darker [melanic form]. Before industrialization almost all the peppered

moth in England were of white variety. After 1840s the population of the melanic form increased

rapidly especially around the industrial cities. The white form dominated in the rural non polluted

areas.

[i] Explain why mutant [melanic] form is dominated in the industrial [polluted] areas.

[2 marks]

……………………………………………………………………………………………………

……………………………………………………………………………………………………

……………………………………………………………………………………………………

……………………………………………………………………………………………………

[ii] Discuss why the lighter [non melanic] form is dominated in rural [non polluted]

areas. [2 marks]

……………………………………………………………………………………………………

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……………………………………………………………………………………………………

……………………………………………………………………………………………………

……………………………………………………………………………………………………

[iii] What factor could have led to the differences in population size of the two

varieties in the two areas? [1 mark]

……………………………………………………………………………………………………

……………………………………………………………………………………………………

[iv] State the advantages of natural selection. [2 marks]

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4. The diagram below represents a structure used for gaseous exchange in a woody plant.

(a). Name the part labeled A and B. [2 marks]

A……………………………………………………………………………………

B……………………………………………………………………………………

(b). Name the gases marked by arrows X and Y. [2 marks]

X……………………………………………………………………………………

Y……………………………………………………………………………………

(c). Give the function of the part labeled B. [1 mark]

……………………………………………………………………………………………………

……………………………………………………………………………………………………

(d). Name the physiological process that results in the production of gas X in the plant

tissues. [1 mark]

……………………………………………………………………………………………………

……………………………………………………………………………………………………

(e). Why does low oxygen concentration in the soil result in reduced mineral on

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absorption by root hair of plants? [2 marks]

……………………………………………………………………………………………………

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……………………………………………………………………………………………………

……………………………………………………………………………………………………

4. The following experiment was set up by a form one class. After an hour, the contents of

the visking tubing and the beaker were tested using iodine solution and benedict’s

solution.

Record in the table below the expected observations after the contents in set up A and B were

tested using iodine solution and benedict’s solution. [8 marks]

Visking tubing Beaker

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Set up Iodine solution Benedicts solution Iodine solution Benedict’s

solution A

B

SECTION B [40 MARKS]

Answer question 6 (compulsory) and either question 7 or 8.

6. An experiment to investigate the population of a certain type of micro-organism was carried

out. Two petri-dishes labeled X and Y were used into the petri-dish labeled X, 60ml of a

culture medium were added while 15ml of the same culture medium were placed in the petri-

dish labeled Y. Equal numbers of micro-organisms were introduced in both petri-dishes. The

set-ups were incubated at 35°C. The number of micro-organisms in each petri-dish was

determined at regular intervals for a period of 60 hours. The results were as shown in the

graph below.

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[a] At what intervals were the numbers of micro-organisms determined. [1 mark]

……………………………………………………………………………………………………

……………………………………………………………………………………………………

……………………………………………………………………………………………………

……………………………………………………………………………………………………

……………………………………………………………………………………………………

[b] After how many hours was the population in each petri-dish highest? Indicate the

population in each case

Petri-dish X:…………………………………………………………[2 marks]

Time………………………………………………………………………………….

Population:…………………………………………………………………………..

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Petri-dish Y:……………………………………………………………[2 marks]

Time………………………………………………………………………………….

Population:…………………………………………………………………………..

[c]. After how many hours was the difference in the two populations greatest? [1 mark]

……………………………………………………………………………………………………

……………………………………………………………………………………………………

[d]. Account for the shape of curve Y between.

[i]. 0 – 5 hours [2 marks]

……………………………………………………………………………………………………

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[ii]. 5 - 25 hours [2 marks]

……………………………………………………………………………………………………

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[iii]. 25 – 50 hours [2 marks]

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……………………………………………………………………………………………………

[e]. Account for the high numbers of micro-organisms in petri-dish X after 25 hours.

[2 marks]

……………………………………………………………………………………………………

……………………………………………………………………………………………………

……………………………………………………………………………………………………

……………………………………………………………………………………………………

……………………………………………………………………………………………………

[f]. With reasons give the effects on the population of micro-organisms if after 10

hours the petri-dishes were kept at;

[i]. 10°C

……………………………………………………………………………………………………

……………………………………………………………………………………………………

Reason [2 marks]

……………………………………………………………………………………………………

……………………………………………………………………………………………………

[ii]. 60°C

……………………………………………………………………………………………………

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Reason [2 marks]

……………………………………………………………………………………………………

……………………………………………………………………………………………………

7. Describe how the mammalian eye is adapted to its functions. [20 marks]

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OR

8. (a) Explain how plants can eliminate metabolic waste products. [8 marks]

(b) Explain why plants have less specialized excretory organs as compared to animals.

[5 marks]

(c) How is the kidney adapted to perform its function? [7 marks]

….…………………………………………………………………………………………………

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PROJECTION NO. 23

NAME___________________________________ INDEX NO._______________________ SCHOOL__________________________________ DATE___________________________ CANDIDATE’S SIGNATURE______________________ 231/2 BIOLOGY (THEORY) PAPER 2 TIME: 2 HOURS

INSTRUCTION TO CANDIDATES 1. Write your name and Index number in the spaces provided above 2. Sign and write the date of the examination in the spaces provided above 3. This paper consists of two sections; A and B. 4. Answer ALL questions in Section A in the spaces provided 5. In Section B answer question 6 (compulsory) and either 7 or 8 in the spaces provided after question 8. FOR EXAMINER’S USE ONLY


A

1 2 3 4 5

8 8 8 8 8

B

6 7 or 8

20 20 20

TOTAL SCORE

80 MARKS

SECTION A (40MARKS)

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Answer ALL questions in this section in the spaces provided. 1. The set up below was used to investigate a certain process.

Glucose solution was boiled and the olive oil added on top. It was then allowed to cool before the yeast suspension was added.

(a) Name the biological process being investigated (1mk) ……………………………………………………………………………………………………………………………….………………….. …………………………………………………………………………………………………………………………………………………….

(b) Why was the glucose solution boiled (1mk) ………………………………………………………………………………………………………………………………………………….. ……………………………………………………………………………………………………………………………………….…………

(d) What is the importance of cooling the glucose solution before adding the yeast? (1mk)

……………………………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………………………... (d) What is the role of olive oil in the experiment (1mk) …………………………………………………………………………………………………………………………………………………………….. ……………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………….

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(e) What will be observed in the lime water at the end of the experiment (1mk)

…………………………………………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………………………………………

(f) Suggest what would be observed if a thermometer reading 250c was inserted

in the glucose solution with the yeast suspension (2mks) ………………………………………………………………………………………………………………………………………………. ………………………………………………………………………………………………………………………………………………. ……………………………………………………………………………………………………………………………………………….

(g) Suggest a control experiment for this set up (1mk) ……………………………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………………………… 2. In an investigation a variety of a plant grown seeds with white seed coats were crossed with a plant

grown from seeds with yellow seed coats. All the seeds obtained in the first filial (F1) generation had white seed coats.

(a) Using letter W to represent the gene for white seed coat, work out the genotypes of the F1

generation. Show your working (3mks)

(b) If the F1 generation was selfed, determine the phenotypic ratio of the second filial (F2) generation. Show your working. (4mks)

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(c) If the total number of seeds produced in F2 generation was 16,000, calculate the number of seeds with yellow seed coats. Show your working. (1mk)

3. The set ups below were used in an experiment to demonstrate a certain physiological process.

(a) State the physiological process being demonstrated (1mk) …………………………………………………………………………………………………………………………………………………………. ………………………………………………………………………………………………………………………………………………………….

(b) Explain the results at the end of the experiment (3mks) …………………………………………………………………………………………………………………………………………………….. …………………………………………………………………………………………………………………………………………………….. ……………………………………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………………………………………………

(c) (i) What role does the visking tubing serve in the experiment (1mk)

……………………………………………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………………………………………………

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(ii) Name the structure in a plant cell with similar properties as visking tubing (1mk) ………………………………………………………………………………………………………………………………………. ……………………………………………………………………………………………………………………………………….

(d) State the significance of the process being investigated in (a) above in plants (2mks)

…………………………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………. 4. (a) Briefly discuss how the following gives evidences on specification: -

i) Cell biology (2mks) ………………………………………………………………………………………………………………………………. ………………………………………………………………………………………………………………………………. ……………………………………………………………………………………………………………………………….

ii) Comparative embryology (2mks) ……………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………….. ………………………………………………………………………………………………………………………………………..

(b) State one limitation of using fossil records as an evidence of organic evolution (1mk)

……………………………………………………………………………………………………………………………………….. ………………………………………………………………………………………………………………………………………… (c) i) What is meant by the term vestigial structure (1 mk) ………………………………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………………………………. ii) Name two examples of vestigial structures in man (2mks) ………………………………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………………………………...

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(a) State part of plant where this section was obtained from (1mk) ……………………………………………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………………………………………………

5. The information given below was obtained in a certain ecosystem Organism Biomass Green plants 95 Lizards 15 Praying Mantis 7 Predatory birds 14 Moths 20

Grass hoppers 30 Herbivorous bugs 18

(a) Construct a labeled pyramid of biomass (2mks)

(b) (i) Construct four step food chains (2mks)

(ii) State three ways in which energy is lost in an ecosystem (3mks) ………………………………………………………………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………………………………………………………………… (iii) From the data given above state two groups of animals competing for the same

resource (2mks) ………………………………………………………………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………………………………………………………………

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SECTION B (40 MARKS) Answer question 6 (compulsory) and either question 7 or 8 in the spaces provided after question 8. 6. Two persons X and Y drunk volume of concentrated solutions of glucose. The amount of glucose in

their blood was determined at intervals. The results are as shown in the table below.

Time (Min) Glucose level in blood (mg/100cm3)

X Y

0 87 84

15 112 123

30 139 170

45 116 188

60 100 208

90 95 202

120 92 144 150 88 123

a) On the grid provided, plot graphs of glucose level in the blood of X and Y

against time, on the same axis. (8mks)

What was the concentration of glucose in blood of X and Y at 20th minote? (2mks) b)

X ……………………………………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………………………………….. Y

…………………………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………………………….

c) Suggest why the glucose level in person X stopped rising after 30 minutes while that of person Y kept on rising (2mks)

d) Account on decrease in glucose level in person X after 30 minutes and Y after 60 minutes. (4mks)

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e) Name the compound that stores energy released during oxidation of glucose in cells (1mk) ………………………………………………………………………………………………………………………………………….. …………………………………………………………………………………………………………………………………………….

f) Explain what happens to excess amino acids in man (2mks)

…………………………………………………………………………………………………………………………………………….. ……………………………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………………………….

g) State the assimilation of fatty acids and glycerol in man (1mk) ………………………………………………………………………………………………………………………………………………. ……………………………………………………………………………………………………………………………………………….

8. Describe how seeds and fruits are adapted to their various methods of dispersal (20mks)

8. (a) What is meant by the term digestion (2mks) (b) Describe how the mammalian small intestine is adapted to its function (18mks)

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PROJECTION NO. 24

NAME………………………………………………………………………………………… INDEX

NO……………………........................

231/2 CANDIDATE’S SIGN………….….….….…..

BIOLOGY

PAPER 2 DATE……….…………………………………

(THEORY)

TIME: 2 HOURS


(a) Write your Name, Index Number and School in the spaces provided above.

(b) Sign and write the date of examination in the spaces provided above.

(c) This paper consists of two Section; A and B.

(d) Answer all the questions in Section A in the spaces provided.

(e) In Section B answer question 6 (Compulsory) and either question 7 or 8 in the


FOR EXAMINER’S USE ONLY:


Score

Candidates

Score

A

1 8

2 8

3 8

4 8

5 8

B 6 20

7 20

8 20

Total Score 80

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Answer all the questions in the spaces provided.

1. The figure below shows the effect of light intensity on the exchange of carbon (IV) oxide

between a green leaf and the air around it.

(a)Account for the effect of increasing light intensity on the rate of uptake of carbon (IV)

oxide. (4 marks)

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

(b) What is the name given to point X? (1 mark)

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(c) Explain why at point X, the carbon (IV) oxide taken in is equal to carbon (IV) given out

by the plant. (3 marks)

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

2. (a) The diagram below shows the side view of a human brain.

Which letter represent the part of the brain which; (2 marks)

(i) Control voluntary movements of the body.

_____________________________________________________________________

(ii) Is more developed in birds and fish than in man.

_____________________________________________________________________

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(b) The diagram below shows the arrangement of cones and rods in retina of the eye.

With reasons identify the following cells. (6 marks)

M__________________________________________________________________________

Reason(s)

___________________________________________________________________________

___________________________________________________________________________

N__________________________________________________________________________

Reason

__________________________________________________________________________

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P___________________________________________________________________________

Reason ______________________________________________________________________

___________________________________________________________________________

3. A person met a leopard as he walked along a forest path. His adrenal gland secreted

adrenaline to prepare him to run away. What was the effect of adrenaline on his?

(a) Circulatory system. (5 marks)

____________________________________________________________________________

____________________________________________________________________________

____________________________________________________________________________

____________________________________________________________________________

____________________________________________________________________________

____________________________________________________________________________

(b) Respiratory system? (3 marks)

____________________________________________________________________________

____________________________________________________________________________

____________________________________________________________________________

____________________________________________________________________________

4. (a) Name the sex chromosome in humans that is considered to be ‘genetically empty’. (1 mark)

___________________________________________________________________________

___________________________________________________________________________

(b) Colour blindness is a human disease inherited through a recessive gene carried on the X

chromosome. If the carrier female married a normal male. Work out the expected

genotypes

of their children. Show all your working. (Let n stand for colour blindness allele). (5 marks)

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(c) Work out the genotypic ratio of the off springs. (1 mark)

____________________________________________________________________________

_____________________________________________________________________________

(d) Work out the probability of the first child being a carrier female. (1 mark)

____________________________________________________________________________

____________________________________________________________________________

____________________________________________________________________________

5. During a biological practical lesson on estimation of the size of onion epidermal cells. Form one

student from Huduma Bora Academy placed a transparent ruler across the field of view, brought

the millimeter marks to focus and observed them as illustrated below. Give your answer in

micrometers.

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They then prepared a temporary slides of the onion epidermal cells and observed the

arrangement of cells as illustrated below:

(a) Work out:

(i) Length of each cell. (2 marks)

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

(ii) The width of each cell. (2 marks)

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

(b) State two limitations of using the above method of in estimating the size of cells.(2 marks)

___________________________________________________________________________

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(c) Give a reason why using the onion epidermis is more suitable than using a whole scale of

leaf of an onion bulb. (1 mark)

___________________________________________________________________________

__________________________________________________________________________

(d) A part from iodine solution, identify a stain that was probably used by the students to make

observation clearer. (1 mark)

_________________________________________________________________________

___________________________________________________________________________


Attempt question 6 (Compulsory) and either 7 or 8 in the spaces provided after question 8.

6. A group of students did an experiment to estimate the population of grasshoppers in a plot.

They swept the ground ten times with a net and recorded the number of grasshoppers in each

of the ten samples.

The table below shows the results obtained.

Sample number No of grasshopper Cumulative total

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1 35 35

2 31 66

3 28 94

4 23 117

5 20

6 18

7 15

8 11

9 8

10 6

(a) Complete the cumulative total column in the results table. (3 marks)

(b) (i) On the grid provided plot the number of grasshoppers collected per sample against

the cumulative total. (6 marks)

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(ii) From your graph estimate the population of grasshoppers in the plot.

____________________________________________________________________

____________________________________________________________________

(c) The number of grasshoppers in this study cannot be adequately determined by this method.

What would you consider to be the two main sources of error in this method?

___________________________________________________________________________

____________________________________________________________________________

(d) A fish farmer wanted to know the number of fish in his pond. He collected ten fish from the

pod and labelled each by tying a tag lag label on its fin, and returned the fish to the pond to

mix with other fish. When he later collected a sample of 50 fish from the same pond, he

found out that 4 of them had tag labels.

(i) From the information estimate the total number of fish in the pond.

Show your working. (4 marks)

____________________________________________________________________

____________________________________________________________________

____________________________________________________________________

____________________________________________________________________

(ii) What assumption is made in this method of estimating size of population? (2 marks)

____________________________________________________________________

____________________________________________________________________

____________________________________________________________________

____________________________________________________________________

7. (a) Explain the economic importance of plant excretory products. (10 marks)

(b) Describe the adaptations of the lungs to their function. (10 marks)

8. (a) Describe the role of hormones in the human menstrual cycle. (15 marks)

(b) Explain how halophytes are adapted to their habitat. (5 marks)

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PROJECTION NO. 25

NAME.................................................................................................................... INDEX NO:.......................

CANDIDATE’S SIGNATURE.........................

DATE.........................

231/2

BIOLOGY

PAPER II


a) Write your name and index number in the spaces provided. b) This paper consists of two sections A and B c) Answer all the questions in section A in the spaces provided. d) In section B question 6 is COMPULSORY & choose either question 7 or 8.


SECTION QUESTION MARKS CANDIDATES SCORE

A

1

2

3

4

5

8

8

8

8

8

6 20

B 7 20

8 20

TOTAL 80

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SECTION A (40 Marks)

1. a) Define the term mutation. (1 mark)

.........................................................................................................................................................................

.........................................................................................................................................................................

b) State two human disorders resulting from gene mutation. (2 marks)

.........................................................................................................................................................................

.........................................................................................................................................................................

……………………………………………………………………………………………………………………………………………………………………

c) The diagram below represents a nucleotide

U A G U U A A G

Name the nucleic acid shown above. (1 mark)

......................................................................................................................................................................

…………………………………………………………………………………………………………………………………………………………………

d) Colour blindness is a sex linked trait caused by a recessive gene on the X chromosome. Using the

symbol XN to represent the gene for normal colour vision and Xn to represent the gene for colour

blindness, work out the phenotype of the children born to a normal man and a carrier woman. (4 marks)

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2. The experiment below was set up to investigate a certain physiological process. The glucose solution was first boiled then cooled. The set was left for 24 hours.

a) Suggest two aims of experiment. (2 marks) .........................................................................................................................................................................

........................................................................................................................................................................

.........................................................................................................................................................................

(b) (i) State the expected observations after 24 hours. (2 marks)

.........................................................................................................................................................................

.........................................................................................................................................................................

.........................................................................................................................................................................

(ii) Explain your observations in a (i) above. (2 marks)

...........................................................................................................................................................................

.................................................................................................................................................................

......................................................................................................................................................................

(iii) Why was glucose solution boiled then cooled? (1 mark)

.........................................................................................................................................................................

.........................................................................................................................................................................

(iv) Suggest a control for the experiment. (1 mark)

...........................................................................................................................................................................

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3. To estimate the population in size of crabs in a certain lagoon, traps were laid at random. 400 crabs were caught, marked and released back into the lagoon. Four days later, traps were laid again and 374 crabs were caught. Out of the 374 crabs, 80 were found to be marked.

a) Calculate the population size of the crabs in the lagoon. (3 marks)

b) State two assumptions that were made during the observation. (2 marks) ......................................................................................................................................................................

.........................................................................................................................................................................

.........................................................................................................................................................................

c) What is the name given to this method of estimating the population size? (1 mark) .........................................................................................................................................................................

.........................................................................................................................................................................

d) Below is an example of a food chain.

Napier grass Mouse Snake Hawk

Identify the tropic level occupied by

(i) Napier grass (1 mark) .........................................................................................................................................................................

.........................................................................................................................................................................

(ii) Hawk (1 mark)

.........................................................................................................................................................................

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4. a) Birds have beaks which are structurally modified to different modes of feeding.

(i) What is the name given to such structures in evolution? (1 mark)

.........................................................................................................................................................................

.........................................................................................................................................................................

(ii) What is the name given to the evolution of beaks of birds? (1 mark) .........................................................................................................................................................................

.........................................................................................................................................................................

b) (i) What is meant by “vestigial structures”? (1 mark) .........................................................................................................................................................................

.........................................................................................................................................................................

(iii) Name two vestigial structures present in man. (1 mark) .........................................................................................................................................................................

.........................................................................................................................................................................

c) Bacteria tend to develop resistance to antibiotics after they have been subjected to them for a long period of time. Explain. (2 marks)

.........................................................................................................................................................................

.........................................................................................................................................................................

.........................................................................................................................................................................

d) Explain continental drift as an evidence of evolution. (2 marks) .........................................................................................................................................................................

.........................................................................................................................................................................

.........................................................................................................................................................................

5. a) Name the type of circulatory system found in the members of the class insecta. (1 mark)

.........................................................................................................................................................................

.........................................................................................................................................................................

b) Name the blood vessels that transport blood from:

(i) Small intestines to the liver. (1 mark) .........................................................................................................................................................................

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(ii) Lungs to the heart. (1 mark) .........................................................................................................................................................................

.........................................................................................................................................................................

b) The diagram below shows gaseous exchange in tissues

(i) Name the gas that diffuses

I. to the body cells (1 mark) .........................................................................................................................................................................

.........................................................................................................................................................................

II. from the body cells (1 mark)

.........................................................................................................................................................................

.........................................................................................................................................................................

(ii) Which compound dissociates to release the gas named in (i) I above (1 mark) .........................................................................................................................................................................

.........................................................................................................................................................................

(iii) What is tissue fluid (2 marks)

.........................................................................................................................................................................

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SECTION B (40 Marks)

Answer question 6 (Compulsory) and either question 7 or 8 in the spaces provided.

6. The cells of Tradescantia plant were found to have an average diameter of 2.5ΏM. The cells were placed in varying concentrations of sugar solution. The diameter of the cells in each solution was determined and results obtained were as shown below.

Percentage of sugar

concentration

Diameter of cell (MM)

1 5.0

5 4.0

10 3.0

15 2.0

20 1.5

25 1.0

a) Draw a graph of diameter of cells against percentage of sugar concentration on the graph provided. (6 marks)

b) From the graph determine the concentration of the cell sap. (1 mark)

c) Give an explanation for the average diameter of cells placed in 2.5% sugar solution. (4 marks)

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d) Describe the difference in appearance between cytoplasm before and after cells being placed in 25% sugar solution. (2 marks)

………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………….

e) Account for the appearance of red blood cells when viewed under light microscope after they were placed in 25% sugar solution and left for 10 minutes. (3 marks)

………………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………………

f) State the importance of the process under investigation to the plants. (4 marks)

…………………………………………………………………………………………………………………………………………………………………………

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…………………………………………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………………………………………

7. Describe the process of fertilization in a flowering plant. (20 marks)

8. Describe the structure and functions of the various parts of the human ear. (20 marks)

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PROJECTION NO. 26

Name …………………………………… Index No ………………………..

School ……………………………… Candidates Sign …………………… Date …………………………….. 231/2

Biology Paper 2 (Theory)

TIME: 2 HOURS


1. Write your name and index number in the spaces provided above.

2. Sign and write the date of examination in the space provided above.

3. The paper consists of sections A and B.

4. Answer all questions in section A in the space provided.

5. In section B answer question 6 (compulsory) and either 7 or 8 in the

space provided.

6. Candidates should check the question paper to ascertain that all the

pages are printed as indicated and no question is missing.

For Examiner’s Use Only


A 1 08

2 08

3 08

4 08

5 08

Section B 6 20

7 20

8 20

Total 80

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SECTION A Q 1. (a) i) Name a carbohydrate secreted in the duodenum. (1 mk)

………………………………………………………………………………………………………

………………………………………………………………………………………………………

ii) Name the organ that secretes the carbohydrate you named in (a) (i) above.

(1 mk) ………………………………………………………………………………………………………

……………………………………………………………………………………………………… (b) State the function of carbohydrate (1 mk)

………………………………………………………………………………………………………

………………………………………………………………………………………………………

(c) Name three characteristics of organic catalysts found in the gut. (3 mks)

………………………………………………………………………………………………………

………………………………………………………………………………………………………

(d) State two ways in which food physically digested along the alimentary

Canal (2 mks)

………………………………………………………………………………………………………

………………………………………………………………………………………………………

………………………………………………………………………………………………………

Q2. Proteins are present in a balanced diet. They are broken down into amino

acid, the body cannot store amino acids, and so any excess amino acids are metabolized as shown below.

Excess amino acids

Process S

Non-nitrogen organic compound Urea

Process T

Carbon (IV) oxide + water + energy Removal from the body

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(a) Names the process S and T, stating the organ in which each occurs.

Process Name Organ

S

T

(b) Describe how urea is transported to the site of removal from the body.

(2 mks)

………………………………………………………………………………………………………

………………………………………………………………………………………………………

………………………………………………………………………………………………………

………………………………………………………………………………………………………

(c) State the type of respiration shown, giving a reason to explain your

answer (2 mks)

………………………………………………………………………………………………………

………………………………………………………………………………………………………

………………………………………………………………………………………………………

3. An experiment was set upto investigate the effect of unilateral light on the growth of oat coleoptiles. The diagrams below represent the experiment set

up at the start, and the results at the end of the experiment.

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(a) Account for the results in the experiment set up A. (3 mks)

………………………………………………………………………………………………………

………………………………………………………………………………………………………

………………………………………………………………………………………………………

………………………………………………………………………………………………………

………………………………………………………………………………………………………

………………………………………………………………………………………………………

(b) Explain the purpose of experimental set-up. (3 mks)

B and C.

………………………………………………………………………………………………………

………………………………………………………………………………………………………

………………………………………………………………………………………………………

………………………………………………………………………………………………………

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(c) Explain the results in experimental set ups D and E (2 mks)

………………………………………………………………………………………………………

………………………………………………………………………………………………………

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4. Two bacteria strains were introduced in a culture in a petri dish at the same time and in equal numbers. The graph below represents their population

during the first days. Study the graph and answer the questions that follow:

(a) i) Which species has a better competitive ability? (1 mk)

………………………………………………………………………………………………

………………………………………………………………………………………………

ii) Give a reason for your answer. (1 mk)

…………………………………………………………………………………………..

…………………………………………………………………………………………..

(b) Account for the shape of the curve for species A between.

(i) One day and three days. (2 mks)

…………………………………………………………………………………………

………………………………………………………………………………………….

…………………………………………………………………………………………..

(ii) Three days and seven days (2 mks)

………………………………………………………………………….………………

…………………………………………………………………………………………..

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(c) A natural predator for species A was introduced into the ecosystem with

a reason. State how population of each species would be affected.(3 mks)

………………………………………………………………………………………………..

………………………………………………………………………………………………..

………………………………………………………………………………………………..

…………………………………………………………………………………………………

5. (a) What is meant by genetically modified organism. (1 mk)

…………………………………………………………….………………………………….

…………………………………………………………………………………………………

(b) Njoki is an albino. Her husband Mwenda has normal skin colour. Two of their children have normal skin colour while two are albinos.

(i) Give the genotypes of Njoki and Mwenda. (2 mks)

Njoki ……………………………………………

Mwenda ………………………………………..

(ii) Illustrate the cross between the two parents. (4mks)

………………………………………………………………………………………

………………………………………………………………………………………

………………………………………………………………………………………

(iii) Give the phenotypic ratio of offsprings. (1 mk)

………………………………………………………………………………………

………………………………………………………………………………………

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SECTION: B

The table below shows the changes observed in the dry weight (in milligrams) of

a barley seedling, its embryo and endosperm during the first ten days after the onset of germination.

DRY WEIGHT IN MILLIGRAMS

TIME (DAYS) EMBRYO ENDOSPERM WHOLE SEEDLING

0 2 41 45

2 2 39 43

4 7 32 41

6 15 21 38

8 22 11 35

10 35 6 43

(a) Using a suitable scales on the same axis, plot graphs of dry weight of

embryo endosperm and whole seedling against time. (8 mks)

(b) State and account for the changes in dry weight shown by:

(i) Embryo (4 mks)

………………………………………………………………………………………………………

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………………………………………………………………………………………………………

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(ii) Endosperm (4 mks)

………………………………………………………………………………………………………

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………………………………………………………………………………………………………

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(c) Explain the role of water during germination. (4 mks)

………………………………………………………………………………………………………

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………………………………………………………………………………………………………

………………………………………………………………………………………………………

………………………………………………………………………………………………………

7. (a) Describe one method which can be used to measure growth rate of a

single leaf plant (6 mks)

………………………………………………………………………………………………………

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………………………………………………………………………………………………………

………………………………………………………………………………………………………

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………………………………………………………………………………………………………

(b) Describe secondary thickening in flowering plants. (14 mks)

8. (a) State two factors which increase the rate of mutation. (2 mks)

(b) Describe the various types of chromosome mutations and their effects in human beings. (18mks)

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………………………………………………………………………………………………………

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PROJECTION NO. 27

NAME……………………………………………………….. INDEX NO……………………........................

231/2 CANDIDATE’S SIGN………….….….….…..

BIOLOGY

PAPER 2 DATE……….…………………………………

(THEORY)

TIME: 2 HOURS


• Write your name, index number in the spaces provided above.


• This paper consists of TWO Sections; A and B.


• In Section B answer question 6 (Compulsory) and either question 7 or 8 in the space provided after question 8.




Score

Candidate’s

Score

A

1 5

2 8

3 8

4 10

5 9

B 6 20

7 20

8 20

Total Score 80

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Answer all the questions in this section in the spaces provided:

1. Below is a diagram of a structure found in plants?

(a) (i) Identify the structure. (1mk)

___________________________________________________________________________

___________________________________________________________________________

(ii) Name the parts labelled M and N.

M ________________________________________________________ (1mk)

N _________________________________________________________ (1mk)

(b) Explain why cross-pollination is more advantageous to a plant species than self-pollination. (2mks)

____________________________________________________________________________

____________________________________________________________________________

____________________________________________________________________________

____________________________________________________________________________

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2. The diagram below represents two states of blood vessels in human skin under two different

environmental conditions.

(a) Identify process A and B. (2mks)

A __________________________________________________________________________

B __________________________________________________________________________

(b) What environmental conditions would make the vessel to be in the state (i)? (1mk)

____________________________________________________________________________

(c) Under certain conditions, carbon (IV) oxide concentration in the blood of mammals rises above normal levels. State two physiological changes that occur to bring carbon (IV)

oxide level back to normal.

____________________________________________________________________________

____________________________________________________________________________

____________________________________________________________________________

____________________________________________________________________________

(d) Why does a fresh wound bleed more in hot weather than in cold weather? (1mk)

____________________________________________________________________________

____________________________________________________________________________

____________________________________________________________________________

(e) A certain organ R was surgically removed from a rat. Later a drastic increase in glucose

level was observed in the blood. Substance S was injected into the animal’s blood.

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The whole process reversed.

Identify:

(i) Organ R. _________________________________________________ (1mk)

(ii) Substance S. ______________________________________________ (1mk)

3. The diagrams below illustrate two common bacteria A and B that causes typhoid and cholera

respectively in humans.

(a) (i) Identify bacteria A and B. (2mks)

A ____________________________________________________________________

B ____________________________________________________________________

(ii) Name the kingdom to which they belong. (1mk)

______________________________________________________________________

(b) (i) Name the structures labelled X and Y. (2mks)

X ____________________________________________________________________

Y ____________________________________________________________________

(ii) Suggest the role of structures X and Y. (1mk)

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______________________________________________________________________

_______________________________________________________________________

(c) State two adaptive features of organism B. (2mks)

____________________________________________________________________________

____________________________________________________________________________

____________________________________________________________________________

____________________________________________________________________________

4. The table below shows the number of leopards and impala in a grassland park over a period of

six years.

(a) (i) What was the average number of impala in the park during the six years? (2mks)

______________________________________________________________________

(ii) Account for the decrease in the number of leopards between the 4th and 6th year. (4mks)

______________________________________________________________________

______________________________________________________________________

______________________________________________________________________

______________________________________________________________________

(b) Identify the trophic level occupied by

(i) Leopards. (1mk)

Time in years 1 2 3 4 5 6

Number of impala 360 498 546 216 120 72

Number of leopards 11 17 25 7 3 2

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______________________________________________________________________

(ii) Tick feeding on the leopard. (1mk)

______________________________________________________________________

(c) The two pyramids shown below were obtained in the park.

I II

Identify each type of pyramid. (2mks)

I

___________________________________________________________________________

II __________________________________________________________________________

5. A normal man has children with a haemophilia woman. Their son marries and has children with

a woman who carries the gene but does not suffer from the disorder.

(a) (i) Carry out a genetic cross to show the percentage of the sons who are haemophiliac.

Use letter H to demote the gene for lack of haemophilia. (5mks)

(ii) Why do most men suffer from haemophilia than women? (2mks)

______________________________________________________________________

______________________________________________________________________

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______________________________________________________________________

______________________________________________________________________

(iii) Identify two ways in which blood group inheritance in humans contradict mendel’s findings and conclusion in his monohybrid experiment. (2mks)

______________________________________________________________________

______________________________________________________________________

______________________________________________________________________

______________________________________________________________________


Answer question 6 (Compulsory) and EITHER question 7 or 8 in the spaces provided after

question 8.

6. The relationship between oxygen concentration and sugar consumption in isolated roots of

sorghum was determined. The results are shown in the table below. The loss of sugar and

potassium uptake are in arbitrary units.

% Oxygen concentration

0 5 10 15 20 100

Sugar loss 15 20 42 45 45 48

Potassium gain 5 55 70 73 75 70

(a) Plot graphs of sugar loss and potassium gain against percentage of oxygen concentration in the same axis. (6mks)

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(b) Name the process by which potassium is taken in by root hairs. Give reasons for your answer.

Process:

________________________________________________________ (1mk)

Reasons. (1mk)

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

(c) Account for the sugar loss and potassium gain at: (i) 0% oxygen concentration. (2mks)

____________________________________________________________________

____________________________________________________________________

____________________________________________________________________

____________________________________________________________________

(ii) Between 5% and 20% oxygen concentration. (2mks)

____________________________________________________________________

____________________________________________________________________

____________________________________________________________________

____________________________________________________________________

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(d) Apart from oxygen concentration, give two other factors that are necessary for the above process. (2mks)

___________________________________________________________________________

__________________________________________________________________________

(e) State two ways in which you can stop the above process from taking place. (2mks)

___________________________________________________________________________

___________________________________________________________________________

(f) Name two main areas in the mammalian body where the above process is involved. (2mks)

__________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

7. Describe the various evidence which support the theory of organic evolution. (20mks)

8. Describe the functions of the various components of the mammalian blood. (20mks)

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________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

_______________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

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PROJECTION NO. 28

NAME ........................................................................ ..............

INDEX NO................................

SCHOOL..................................................DATES.......................

CANDIDATES’ SIGN...................

231/2

BIOLOGY

PAPER 2

(THEORY)

Time: 2 Hours

Time: 2 Hours

Kenya Certificate of Secondary Education (K.C.S.E)


a) Write your name and index number in spaces provided above

b) This paper consists of two sections A and B.

c) Answer ALL the questions In section A in the space provided.

d) In section B answer question 6 (compulsory) and either

question 7 or 8 in the spaces provided after question 8.

1. The diagram below shows the exchange site between circulatory system and body

cells.

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a) State two adaptations of the capillaries. (2mks)

............................................................................................................................................................

............................................................................................................................................................

............................................................................................................................................................

b) (i) Name the blood cells labeled B. (1mk)

............................................................................................................................................................

............................................................................................................................................................

(ii) State the gas that diffuses from B to the tissue cells. (1mk)

............................................................................................................................................................

............................................................................................................................................................

c) State two functions of the part labeled A. (2mks)

............................................................................................................................................................

............................................................................................................................................................

............................................................................................................................................................

d) Name the blood vessel with the highest concentration of;

Oxygen. (1mk)

............................................................................................................................................................

............................................................................................................................................................

Urea. (1mk)

............................................................................................................................................................

………………………………………………………………………………………………………

2. The table below gives information about an aquarium community which is

ecologically balanced.

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a) What do you understand by the term ecological balance? (1mk)

............................................................................................................................................................

............................................................................................................................................................

………………………………………………………………………………………………………

b) Calculate the total biomass of the aquarium. (2mks)

............................................................................................................................................................

............................................................................................................................................................

............................................................................................................................................................

............................................................................................................................................................

c) Which organism in the table is? (2mks)

.

i) Primary producer (2mks)

............................................................................................................................................................

............................................................................................................................................................

ii) Secondary consumer

............................................................................................................................................................

.......................................................................................................................................................... ..

d) Construct a food web of the aquarium. (3mks)

............................................................................................................................................................

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............................................................................................................................................................

.......................................................................................................................................... ..................

............................................................................................................................................................

............................................................................................................................................................

3. In human beings, a downward pointed frontal hairline (“windows peak”) is a heritable

trait. A person with windows peak always has at least one parent who has his trait; whereas

persons with frontal hairline may occur in families in which one or even both parents have

windows peak. Using B and b to symbolize genes for this trait.

a) Determination the f1 generation if a homozygous windows peak male parent is married to

Homozygous frontal hairline female parent. (4mks)

............................................................................................................................................................

............................................................................................................................................................

............................................................................................................................................................

............................................................................................................................................................

............................................................................................................................................................

............................................................................................................................................................

............................................................................................................................................................

............................................................................................................................................................

b) State two causes of variations. 2mk)

............................................................................................................................................................

............................................................................................................................................................

............................................................................................................................................................

c) Name two examples of discontinuous variation. (2mks)

............................................................................................................................................................

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............................................................................................................................................................

............................................................................................................................................................

3. The drawing below represents a mature bread mould (rhizopus). Study it and answer

the questions which follow.

a) Name the structures labeled A, B and C. (3mks)

A.............................................................................................................................................

B…………………………………………………………………………………………….

C............................................................................................................................ .................

b) Identify the type of asexual reproduction represented in the diagram (1mk)

............................................................................................................................................................

............................................................................................................................................................

c) Give one function of structure C. (1mk)

............................................................................................................................................................

............................................................................................................................................................

d) Define the term fertilization. (1mk)

............................................................................................................................................................

............................................................................................................................................................

………………………………………………………………………………………………………

i) Compare an ovum cell and a zygote. (2mks)

............................................................................................................................................................

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............................................................................................................................................................

............................................................................................................................................................

............................................................................................................................................................

............................................................................................................................................................

5. The diagram below shows three different types of neurons along a reflex.

a) Identify the neuron labeled 1, 2 and 3 (3mks)

1............................................................................................................................ ......

2..................................................................................................................................

3............................................................................................................................ ......

b) Using arrow show the direction of impulse transmission on the diagram. (1mks)

c) Name the part of the spinal cord where the cell bodies of neuron 2 and 3 are

. located. (1mk)

................................................................................................................................................ ............

............................................................................................................................................................

d) Describe the transmission impulses across the part labeled P. (3mks)

............................................................................................................................................................

............................................................................................................................................................

............................................................................................................................................................

............................................................................................................................................................

.................................................................................................................................................... ........

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............................................................................................................................................................

............................................................................................................................................................

............................................................................................................................................................

6. Answer QUESTION 6(COMPULSARY) AND EITHER 7 OR 8 IN THE SPACES

PROVIDED.

A man carried out an experiment to find out the effect of water and 0.9% salt solution on

urine production.on the first day he drunk one liter of water(X).on the second day he repeated the

experiment but instead of water,he drunk one litre of 0.9% salt solution(Y).

The experimental results are shown in the table below.

Time

(hours)

0.0 1.0 1.5 2.5 4.5 5.5 6.5 7.5

Amount

of urine

produced

in cm3per

hour

X 80 60 360 520 60 100 40 60

Y 40 40 40 45 100 60 80 100

a) Using a suitable scale draw graphs of urine produced in cm3per hour against time. (8mks)

b). From the graph determine the:

(i) Amount of urine produced in the second hour when the man had drunk. (1mk)

(iii) The rate of urine production between the first and second hour after the man had

drunk one liters of water. Show your working.

c) What does the shape of the curve representing column X tell us about the rate of urine

production?

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d) Explain the differences between the rate of production in graph X and Y. (2mks)

e) Why do you think drinking one liter of (0.9%) sodium chloride solution made little

difference to the output? (2mks)

............................................................................................................................................................

............................................................................................................................................................

............................................................................................................................................................

f. What does the comparisons of the results of the experiment indicate about the effect of

the Kidneys on the osmotic pressure of the blood plasma? (2mks)

............................................................................................................................................................

............................................................................................................................................................

............................................................................................................................................................

............................................................................................................................................................

g. What does the results of the experiment indicate about the effect of the kidneys on the

volume of blood plasma? (2mks)

............................................................................................................................................................

............................................................................................................................................................

............................................................................................................................................................

............................................................................................................................................................

7. a) Describe how you will estimate the growth rate of a seedling? (6mk)

b) Explain the process of secondary thickening in flowering plants? (14mks)

8. Describe the following stages of photosynthesis. (20 mks)

a. Light stage (10mks)

b. Dark stage (10mks)

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............................................................................................................................................................

............................................................................................................................................................

............................................................................................................................................................

............................................................................................................................................................

............................................................................................................................................................

............................................................................................................................................................

............................................................................................................................................................

............................................................................................................................................................

............................................................................................................................................................

............................................................................................................................................................

............................................................................................................................................................

............................................................................................................................................................

............................................................................................................................................................

.................................................................................................................. ..........................................

............................................................................................................................................................

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............................................................................................................................................................

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PROJECTION NO. 29

NAME…………………………………………………INDEX NO………………………. …………...…

SCHOOL……………………………………………...…….

CANDIDATE’S SIGNATURE………………….

DATE………………………………………..

231/2

BIOLOGY

PAPER 2

(THEORY)

TIME: 2 HOURS

INSTRUCTIONS TO CANDIDATES • Write your name and Index number in the spaces provided.

• Answer all the questions in section A in the spaces provided on the question paper.

• In section B, answer question 6 (compulsory) and either question 7 or 8 in the spaces provided

after question 8.


Section Question Maximum Score Candidate’s Score

A 1 - 8

2 8

3 8

4 8

5 8

B 6 20

7 20

8 20

TOTAL SCORE 80

This paper consist s of 12 printed pages candidates should check the question paper to ensure all the pages are3

printed as indicated and no questions are missing.

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SECTION A

1. The diagram below represents circulatory system in animal.

(a) Name the class whose members show the circulatory system shown above. (1mk)

………………………………………………………………………………………………

………………………………………………………………………………………………

(b) (i) Name the parts labeled I and II (2mks)

I………………………………………………………………………………………

II……………………………………………………………………………………..

(ii) State two difference in blood composition and flow in blood vessel R and

P. (2mks)

………………………………………………………………………………………………

………………………………………………………………………………………………

………………………………………………………………………………………………

……………………………………………………………………………………………….

(d) (i) Explain why root pressure stops when a root is deprived of oxygen. (1mk)

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……………………………………………………………………………………………….

………………………………………………………………………………………………

(ii) Explain why a plant stomata may close in a hot sunny afternoon only to re

open a short while later. (2mks)

………………………………………………………………………………………………

………………………………………………………………………………………………

………………………………………………………………………………………………

………………………………………………………………………………………………

2. A farmer mated his dark red cow to a while bull. The cow gave birth to a light red calf.

(a) State why the calf is light red and not dark red or white. (1mk)

………………………………………………………………………………………………

………………………………………………………………………………………………

(b) If a light red bull is mated to a dark red cow, work out using a genetic cross:

(i) The genotypes of the offspring. (4mks)

(ii) The genotypic ratio of the offspring. (1mk)

………………………………………………………………………………………………

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………………………………………………………………………………………………

(iii) The phenotypic ratio of the offspring. (1mk)

………………………………………………………………………………………………

………………………………………………………………………………………………

(iv) The probability of getting a light red offspring from the cross. (1mk)

………………………………………………………………………………………………

………………………………………………………………………………………………

3. A group of students set up an experiment to investigate a certain physiological process.

The set up was as shown below:

After sometimes, the students observed that a sugar solution was formed and its level rose



………………………………………………………………………………………………

……………………………………………………………………………………………....

(b) Account for the formation of sugar solution and its rise in level. (3mks)

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………………………………………………………………………………………………

………………………………………………………………………………………………

………………………………………………………………………………………………

………………………………………………………………………………………………

………………………………………………………………………………………………

………………………………………………………………………………………………

(c) Suggest the result that the students would obtain if they repeated the experiment

using a boiled pawpaw. Give reasons. (2mks)

………………………………………………………………………………………………

………………………………………………………………………………………………

………………………………………………………………………………………………

………………………………………………………………………………………………

(d) State two importance of the physiological process named in 3(a) above to plants.

(2mks)

………………………………………………………………………………………………

………………………………………………………………………………………………

……………………………………………………………………………………………….

4. (a) Explain the term Eutrophication. (3mks)

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………………………………………………………………………………………………

………………………………………………………………………………………………

………………………………………………………………………………………………

………………………………………………………………………………………………

………………………………………………………………………………………………

(b) How does eutrophication lead to death of fish in a water body? (3mks)

………………………………………………………………………………………………

………………………………………………………………………………………………

………………………………………………………………………………………………

………………………………………………………………………………………………

(c) Persistent use of agricultural inorganic fertilizers lead to loss of soil fertility.

Account for this observation. (2mks)

………………………………………………………………………………………………

………………………………………………………………………………………………

………………………………………………………………………………………………

……………………………………………………………………………………………...

.

5. An ecological study of woodland was carried out and the following observations recorded.

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• Rabbits feed on plants

• Hawks feed on rabbits and small birds

• Snails feed on plants

• Fox feed on rabbits and small birds.

(a) Using the above observations, construct a food web. (3mks)

(b) From your food web;

(i) Draw a food chain that ends with hawks as tertiary consumers. (1mk)

………………………………………………………………………………………………

………………………………………………………………………………………………

(ii) Name two carnivores that compete in the woodland and state the food they

compete for. (1mk)

………………………………………………………………………………………………

……………………………………………………………………………………………...

(c) Suggest the most likely method of sampling used to estimate the rabbit population

in the woodland . (1mk)

………………………………………………………………………………………………

……………………………………………………………………………………………….

(d) State two precautions to be taken when using the sampling method named in (c)

above. (2mks)

………………………………………………………………………………………………

………………………………………………………………………………………………

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………………………………………………………………………………………………

SECTION B: Answer question 6 (compulsory) and either question 7 or 8.

6. An experiment was carried out to investigate the effects of hormones on growth of lateral

buds of three pea plants.

The shoots were treated as follows;

Shoot A – Apical bud was removed

Shoot B – Apical bud was removed and gibberellic acid placed on the cut shoot.

Shoot C - Apical bud was left intact.

The length of branches developed from lateral buds was determined at reular intervals.

The results obtained are as shown in the table below:

Time in days Shoot A Shoot B Shoot C

0

2

4

6

8

10

3

10

28

50

80

118

3

12

48

90

120

152

3

3

8

14

20

26

(a) Using the same axes, draw graphs to show length of branches against time. (8mks)

Length of Shoot in millimeters

millimetrtes

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(b) (i) What was the length of the branch in Shoot B on the 7th day? (1mk)

………………………………………………………………………………………

……………………………………………………………………………………….

(ii) What would be the expected length of the branch developing from Shoot A

on the 11th day? (1mk)

………………………………………………………………………………………………

………………………………………………………………………………………………

(c) Account for the result obtained in the experiment.

(6mks)

………………………………………………………………………………………………

………………………………………………………………………………………………

………………………………………………………………………………………………

………………………………………………………………………………………………

………………………………………………………………………………………………

………………………………………………………………………………………………

………………………………………………………………………………………………

………………………………………………………………………………………………

………………………………………………………………………………………………

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(d) Why was Shoot C included in the experiment? (1mk)

……………………………………………………………………………………………….

………………………………………………………………………………………………

(e) What is the importance of gibberellic acid in Agriculture? (1mk)

………………………………………………………………………………………………

………………………………………………………………………………………………

(f) State two physiological processes that are brought about by the application of

gibberellic acid on plants. (2mks)

………………………………………………………………………………………………

………………………………………………………………………………………………

………………………………………………………………………………………………

………………………………………………………………………………………………

7. Describe the adaptations of a dicotyledonous stem to its functions. (20mks)

8. Describe the economic importance of members in the kingdom fungi giving appropriate

examples where possible. (20mks)

………………………………………………………………………………………………………

………………………………………………………………………………………………………

………………………………………………………………………………………………………

………………………………………………………………………………………………………

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………………………………………………………………………………………………………

………………………………………………………………………………………………………

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……………………………………………………………………………………………………...

………………………………………………………………………………………………………

………………………………………………………………………………………………………

………………………………………………………………………………………………………

………………………………………………………………………………………………………

………………………………………………………………………………………………………

………………………………………………………………………………………………………

………………………………………………………………………………………………………

………………………………………………………………………………………………………

………………………………………………………………………………………………………

………………………………………………………………………………………………………

…………………………………………………………………………….………………………...

………………………………………………………………………………………………………

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………………………………………………………………………………………………………

PROJECTION NO. 30

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NAME……………………………………………………….. INDEX NO……………………........................

231/2 CANDIDATE’S SIGN………….….….….…..

BIOLOGY

PAPER 2 DATE……….…………………………………

(THEORY)

TIME: 2 HOURS


1. Write your Name, Index Number and School in the spaces provided above.

2. Sign and write the date of examination in the spaces provided above.

3. Answer all the questions in the spaces provided.

4. Answers must be written in the spaces provided in the question paper.

5. Additional pages must not be inserted.



Score

Candidates

Score

A

1 8

2 8

3 8

4 8

5 8

B 6 20

7 20

8 20

Total Score 80

1. The diagram below represents a section of a leaf.

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Name the parts labelled V and W. (2mks)

V __________________________________________________________________________

W _________________________________________________________________________

(b) State two adaptations of part labelled X to it’s function. (2mks)

____________________________________________________________________________

____________________________________________________________________________

____________________________________________________________________________

(c) (i) State three end products of photosynthesis. (3mks)

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

(ii) Name the structure where the light stage of photosynthesis occurs. (1mk)

_________________________________________________________________________________

2. Haemophilia is a sex linked characteristic caused by a recessive gene carried on the X chromosome.

A carrier woman marries a normal man. Use letter H to represent the dominant gene.

(a) Work out the phenotypes of F1 generation. (5mks)

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(b) What is the probability of the couple getting a haemophilic son? (1mk)

____________________________________________________________________________

(c) Define the following terms as used in genetics.

(i) Allele. (1mk)

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

(ii) Genetic engineering. (1mk)

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

3. The diagram below represents bread mould (Rhizopus).

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(a) Identify the parts labelled A and B. (2mks)

A __________________________________________________________________________

B __________________________________________________________________________

(b) State the function of parts labelled C. (1mk)

____________________________________________________________________________

(c) List two differences between class chlopoda and diplopoda. (2mks

____________________________________________________________________________

____________________________________________________________________________

____________________________________________________________________________

____________________________________________________________________________

(d) The diagram below represents a section obtained from a plant.

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Classify the plant from which the section was obtained under the following: (2mks)

(i) Division __________________________________________________________

(ii) Class __________________________________________________________

(e) Give two reasons for your answer in d(ii) above. (2mks)

_________________________________________________________________________

____________________________________________________________________________

____________________________________________________________________________

4. The figure below shows the anterior view of a lumbar vertebra.

(a) Name part labelled A - C. (3mks)

A _________________________________________________________________________

B _________________________________________________________________________

C _________________________________________________________________________

(b) What is the function of part D? (1mk)

____________________________________________________________________________

____________________________________________________________________________

(c) Name the structure that is found between two vertebrae. (1mk)

___________________________________________________________________________

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(d) State two important functions of the structure named in (c) above. (2mks)

____________________________________________________________________________

____________________________________________________________________________

____________________________________________________________________________

(e) Name the support tissue in herbaceous plant. (1mk)

____________________________________________________________________________

____________________________________________________________________________

5. The diagram below illustrates the structure of the alveolus.

(a) Name the membranes labelled A and B. (2mks)

A __________________________________________________________________________

B __________________________________________________________________________

(b) Name the gases labelled X and Y. (2mks)

X _________________________________________________________________________

Y _________________________________________________________________________

(c) Name the cell labelled W. (1mk)

W _________________________________________________________________________

(d) State three adaptations of the above structure to it’s function. (3mks)

____________________________________________________________________________

____________________________________________________________________________

____________________________________________________________________________

Oxygenated

blood

Deoxygenated

blood

B

A

W

X Y

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____________________________________________________________________________

SECTION B:

6. Some students used a model to demonstrate the effect of sweating on human body temperature.

Two boiling tubes A and B were filled with hot water. The temperature of water in tubes was

taken at the start of the experiment and then at 5 minutes interval. The surface of tube A was

continuously wiped with a piece of cotton wool soaked in methylated spirit. The results

obtained are shown in the table below.

(a) On the same axes plot graphs of temperature of water in the tubes against time. (6mks)

A B

0 80 80

5 54 67

10 40 59

15 29 52

20 21 47

25 18 46

Time (minutes) Temperature °C in table

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(b) At what rate was water cooling in tube A. (1mk)

____________________________________________________________________________

____________________________________________________________________________

____________________________________________________________________________

(c) Why was tube B included in the set up. (1mk)

____________________________________________________________________________

____________________________________________________________________________

(d) Account for the rate of cooling in tube A. (3mks)

____________________________________________________________________________

____________________________________________________________________________

____________________________________________________________________________

____________________________________________________________________________

(e) State two processes of heat loss in tube B. (2mks)

____________________________________________________________________________

____________________________________________________________________________

(f) What would be the expected results in tube A if it was insulated? (1mk)

____________________________________________________________________________

____________________________________________________________________________

(g) What would the insulation be compared to in: (2mks)

(i) Bird __________________________________________________________________

(ii) Mammals ______________________________________________________________

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(h) Name the structure in human body that detect: (2mks) (i) External temperature changes.

___________________________________________________________________

____________________________________________________________________

(ii) Internal temperature changes.

____________________________________________________________________

____________________________________________________________________

7. (a) Described how the structure of the heart is adapted to it’s function. (10mks)

(b) Describe how the schistosoma is adapted to it’s parasitic mode of life. (10mks)

8. Describe how the structure of mammalian eye is adapted to it’s function. (20mks)

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

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________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

_______________________________________________________________________________________

PROJECTION NO. 31

NAME: …………………………………………. INDEX NO: ……………………………….

SCHOOL: ………………………………………. DATE : ……………………………………

of 744


CANDIDATE’S SIGNATURE:…………………

231/2

BIOLOGY

PAPER 2

(THEORY)

TIME: 2 HOURS


(k) Write your Name and Index Number in the spaces provided.

(l) Sign and write the Date of examination in the spaces provided.

(m) This paper consists of TWO sections A and B.

(n) Answer all questions in section A in the spaces provided.

(o) In section B, answer question 6 (compulsory) and either question 7 or 8 in the spaces provided.



A

1 8

2 8

3 8

4 8

5 8

B

6 20

7 20

8 20

TOTAL 80

(ii) What are the importance of tissue fluid? (2mks)

…………………………………………………………………………………………………

…………………………………………………………………………………………………

………………………………………………………………………………………………….

(d) Name the blood vessel with the highest concentration of: (2mks)

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(i) Glucose

………………………………………………………………………………………………

(ii) Carbon (iv) oxide

…………………………………………………………………………………………………..

3. Below is a diagram of an organism found in water. Study it and answer the following

questions:

(a) State the kingdom in which the organism belongs. (1mk)

………………………………………………………………………………………………

………………………………………………………………………………………………

(b) Name the parts labeled:

B (1mk)

……………………………………………………………………………............................

Y (1mk)

………………………………………………………………………………………………

(c) State the functions of the following parts:

A (1mk)

………………………………………………………………………………………………

………………………………………………………………………………………………

X (1mk)

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………………………………………………………………………………………………

………………………………………………………………………………………………

(d) Explain briefly why the organism is described as eukaryotic. (1mk)

………………………………………………………………………………………………

………………………………………………………………………………………………

………………………………………………………………………………………………

(e) Give two other members that belong to the same kingdom with the above organism.

(2mks)

………………………………………………………………………………………………

………………………………………………………………………………………………

……………………………………………………………………………………………..

4. In an experiment, black mice were crossed and the offspring were black and brown. The gene

for black colour is dominant over that of brown colour.

Using letter B to represent the gene for black colour and b to represent the gene brown colour.

(a) Work out the genotypes of the F1 generation. (4mks)

6. An experiment was carried out to investigate the effect of temperature on the rate of reaction

catalyzed by an enzyme. The results are shown in the table below.

Temperature (0C) Rate of reaction in mg of products per unit time

5

10

15

0.2

0.5

0.8

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20

25

30

35

40

45

50

55

60

1.1

1.5

2.1

3.0

3.7

3.4

2.8

2.1

1.1

(a) On the grid provided, draw a graph of rate of reaction against temperature. (6mks)

PROJECTION NO. 32

231/2

BIOLOGY

PAPER 2

(THEORY)

2 HOURS

of 744


1. A true-breeding purple maize variety was cross-pollinated with true-breeding

yellow maize variety. The offspring produced all purple fruits.

The plants grown from these F1 grains were interbred among each other.

A typical cob of F2 generation is shown bellow:

The yellow fruits are shaded while the purple ones are un-shaded.

a) i) In terms of flowers only, state why it is easier to work out genetic crossing

using maize (1mark)

…………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………….

ii) Count separately the yellow and purple grains and therefore find the ratios

of purple grains to yellow grains. (1mark)

…………………………………………………………………………………..…………………………………..

……………………………………………………………………………………………………………………….

b) Using appropriate symbol, work out a genetic cross for F2 generation. (3marks)

……………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………

……………………………………………………………………………………………………

From the above information, give the dominant gene. (1mark)

……………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………

c) State two practical applications of genetics in identity determination. (2mark)

……………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………….

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2. The flow chart below shows a blood transfusion pathway

a) What three conclusions can you draw from the flow chart? (3marks)

……………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………

b) State two precautions that must be observed during blood transfusion

(2marks)

……………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………

c) Explain how blood clot is formed once blood vessel is injured. (3marks)

……………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………

…………………………………………………………………………………………………..………….

3. The data shown below was taken from Savannah grassland habitat. Examine it

carefully and then answer the questions that follow:

Organism Population

Grasses 1000

Caterpillars 500

Squirrels 300

Frogs 200

Gazelles 300

Elephants 100

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Snakes 50

Hunting

dogs

40

Vultures 40

Lions 40

Hawks 10

a) Draw three food chains. (3marks)

…………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………

b) Draw a pyramid of numbers for a food chain with four trophic levels and

indicate the trophic levels at which each member feeds. (2marks)

………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………

c) State the effect of removing the hunting dogs. (1mark)

…………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………

d) Why is it advisable to feed 100kg of grain to man instead of using it to fatten

steers then supply beef to human population? (2marks)

……………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………..

4 .Study the diagram below and answer the questions that follow

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a) Name the structure represented by the diagram. (1mark)

…………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………….

b) i) Name the parts labelled D and M (2marks)

D ………………………………………………………………………………………

M ……………………………………………………………………………………….

ii) Name the hormones whose sites of action are: (2 mark)

c) Q………………………………………………………………..

d)

d) The contents of part V were boiled with Benedict’s solution and an orange

precipitate was formed. Account for the results. (2marks)

…………………………………………………………………………………………………

…………………………………………………………………………………………………

…………………………………………………………………………………………………

…………………………………………………………………………………………………

…………………………………………………………………………………………………

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5. Form one students from Kitondo School arranged their apparatus as shown

below, to investigate a certain phenomenon. The set up was placed in light.

a) State the likely aim of the set up. (1mark)

……………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………

b) State the role of syringe in the set-up above. (1mark)

……………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………

c) i) Name gas X. (1mark)

……………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………

ii) Write an equation to show how gas X was formed in the set-up. (1mark)

……………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………

d) State three factors that increase the rate of enzyme activity. (3mark)

……………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………

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e) Give a reason why the test tube is immersed in a beaker of water. (1mark)

………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………

SECTION B-(40 MARKS)

Answer question 6(compulsory) and either question 7 or 8 in the spaces

provided after question 8

5. In an investigation, two persons A and B drunk the same amount of glucose

solution. Their blood sugar levels were determined immediately and

thereafter at intervals of one hour for the next six hours. The results were as

shown in the following table:-

6.

Time

(hrs)

Blood glucose

(Mg/100ml)

Person A Person B

0 90 120

1 220 360

2 160 370

3 100 380

4 90 240

5 90 200

6 90 160

a) Draw a graph of blood sugar levels of persons A and B against time on the same

axis. (7marks)

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b) Explain each of the following observation:-

i) Blood sugar level increased in person A between 0 and 1hr. (2mark)

………………………………………………………………………………………

……………………………………………………………………………….………

…………………………………….…………………………………………………

……………………………………………………………………………………….

ii) The blood sugar level dropped in person A between 1 and 4 hours.(2marks)

…………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………

…………………………………………………………………………………………………..

c) From the graph, what is the normal blood glucose sugar level for human

beings? (1mark)

…………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………..

d) Suggest a reason for the high sugar level in person B. (2marks)

……………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………….

e) How can high blood sugar level in person B controlled? (1mark)

……………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………

f) What is the biological significance of maintaining a relatively constant sugar

level in a Human being? (3marks)

………………………………………………………………………………………………………………………..

……………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………

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g) Account for the decrease in the blood glucose level of person B after 4hours.

(2marks)

………………………………………………………………………………………………

…………………………………………………………………………………………………

………………………………………………………………………………………………….

7. a) How is the structure of mammalian gaseous exchange system adapted to its

functions. (10marks)

b) Describe the mechanism of opening and closing of the stomata using

the photosynthetic theory. (10marks)

8. a) What is meant by the term natural selection. (2marks)

b) Describe how natural selection brings about the adaptations of a species to its

environment. (8marks)

c) Distinguish between convergent and divergent evolution (2marks)

d) Discuss four evidences to show that evolution has taken place. (8marks)

…………………………………………………………………………………………………………………………………..

……………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………

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……………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………

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……………………………………………………………………………………………………………………………………

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of 744


PROJECTION NO. 33

NAME:……………………………………………………… INDEX NO:…………………………

SCHOOL:…………………………………………………..DATE:………………………………. SIGN:………………………………..

231/2

BIOLOGY

PAPER 2

(THEORY)

TIME: 2 HOURS




3. This paper consists of Two sections A and B.

4. Answer ALL the questions in section A in the spaces provided.

5. In section B answer question 6 (compulsory) and either 7 or 8 in the spaces provided.

FOR EXAMINERS USE ONLY.


A 1

2

3

4

5

8

8

8

8

8

B 6

7

8

20

20

20

TOTAL 80

of 744




1. Study the diagram below and answer the questions that follow

(a) Identify the structure and state its functions (2mks)

....................................................................................................................................................................

......................................................................................................................................................

(b) (i) Name the parts labelled P and Q (2mks)

....................................................................................................................................................................

......................................................................................................................................................

(ii) State the role of the part labelled R (1mk)

....................................................................................................................................................................

......................................................................................................................................................

(c) How is the structure stated in (a) above adapted to its function (2mks)

....................................................................................................................................................................

......................................................................................................................................................

(d) What is the role of enzyme enterokinase in digestion? (1mk)

....................................................................................................................................................................

.....................................................................................................................................................

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2. (a) The diagram below illustrates a response exhibited by a certain plant tendril. Study and

answer the questions that follow.

(i) Identify the type of response exhibited above. (1mk)

....................................................................................................................................................................

................................................................................................................................................................

(ii) Explain how the response in (a) above occurs (3mks)

....................................................................................................................................................................

................................................................................................................................................................

....................................................................................................................................................................

................................................................................................................................................................

....................................................................................................................................................................

................................................................................................................................................................

(b) The diagram below represents the anterior view of a certain mammalian vertebra

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(i) With a reason, identify the type of vertebra shown above (1mk)

....................................................................................................................................................................

......................................................................................................................................................

(ii) State the role of the parts labelled

R (1mk)

....................................................................................................................................................................

...............................................................................................................................................................

Q (1mk)

....................................................................................................................................................................

................................................................................................................................................................

3. (a) Define the following terms as applied in genetics

(i) Genetic engineering (1mk)

....................................................................................................................................................................

................................................................................................................................................................

(ii) Polyploidy (1mk)

....................................................................................................................................................................

................................................................................................................................................................

(b) When pure breeding red-flowered Mirabilis jalapa plant was crossed with a pure

breeding white flowered plant, the resulting plants produced pink flowers only. Using

letter R to represent the gene for red flowers, and W for white flowers;

(i) Work out the genotypes of the F2 generation (4mks)

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(ii) State the phenotypic ration of the F2 plants (1mk)

.............................................................................................................................................................

(iii) Account for the occurrence of the pink flowered plants in the F1 generation

(1mk)

..................................................................................................................................................................

..................................................................................................................................................................

4. (a) Name the type of circulatory system found in members of the class insecta (1mk)

.............................................................................................................................................................

(b) Name the blood vessels that transport blood from:

(i) Small intestines to the liver (1mk)

.............................................................................................................................................................

(ii) Lungs to the heart (1mk)

.............................................................................................................................................................

(c) The diagram below shows gaseous exchange in tissues


(I) To the body cells (1mk)

.............................................................................................................................................................

(II) From the body cells (1mk)

.............................................................................................................................................................

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(ii) Which compound dissociates to release the gas named in (a)(i) above (1mk)

.............................................................................................................................................................

(d) What is tissue fluid (2mks)

.............................................................................................................................................................

.............................................................................................................................................................

5. (a) Explain how the following abiotic factors affect plants

(i) Wind (2mks)

.............................................................................................................................................................

.............................................................................................................................................................

(ii) Humidity (2mks)

.............................................................................................................................................................

.............................................................................................................................................................

(b) Explain how heavy metals in industrial effluences may accumulate in the bodies of humans to

toxic levels (2mks)

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

(c) Only a small amount of food energy in herbivores is passed onto secondary consumers.

Explain (2mks)

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

of 744



Answer question 6(compulsory) and either question 7 or 8

6. The mean dry weight (mg) of germinating wheat grains was worked out for a whole grain(total dry

weight),endosperm and embryo.

The means were determined at two days interval for fourteen days. The results are as tabulated

below.

Time(days) Dry weight(mg)

Endosperm Embryo Total

0

2

4

6

8

10

12

14

47

44

39

22

10

4

2

2

5

5

8

17

28

35

42

44

52

49

47

39

38

39

44

46

(a) Using the same axis ,draw graphs for dry weight of endosperm, embryo and total against time

(8mks)

(b) What was the average dry weight of embryo on day II? (1mk)

.............................................................................................................................................................

(c) Account for the shape of the curve for

(i) Embryo from day 2 to day 12 (2mks)

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

(ii) Total dry weight (gm) from day 0 to day 14 (2mks)

.............................................................................................................................................................

.................................................................................................................................................................

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.............................................................................................................................................................

.............................................................................................................................................................

(d) After how long was the dry weight of

(i) Endosperm 30g? (1mk)

.............................................................................................................................................................

(ii) Embryo 35g ? (1mk)

.............................................................................................................................................................

(e) (i) Explain the role of water in seed germination (3mks)

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

(ii) Other than water, what two environmental factors are required for seed

germination? (2mks)

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

7. (a) Describe how natural selection brings about the adaptation of a species to its environment

(10mks)

(b) Discuss the economic importance of bacteria (10mks)

8. (a) Describe the methods of excretion in plants (5mks)

(b) Explain the role of hormones in the human female menstrual cycle (15mks)

of 744


.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

of 744


PROJECTION NO. 34

NAME:……………………………………………………… INDEX NO:…………………………

SCHOOL:………………………………………………….. DATE:………………………………. SIGN:………………………………..

231/2

BIOLOGY

PAPER 2

(THEORY)

TIME: 2 HOURS









A 1

2

3

4

5

8

8

8

8

8

B 6

7

8

20

20

20

TOTAL 80

.

SECTION A( 40 MARKS)

of 744



1. The diagram below illustrates and experiment to determine the rate of respiration in a small

insect.

a) Name the chemical compound labelled X and state its function. (2mks)

.............................................................................................................................................................

.............................................................................................................................................................

b) Why is it necessary to place the flask in a water bath. (3mks)

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

c) What changes would you expect to observe in the level of coloured water in the

capillary tube after the experiment has run for five minutes. (1mk)

.............................................................................................................................................................

.............................................................................................................................................................

d) Explain the changes you have started in ( c) above. (3mks)

of 744


.............................................................................................................................................................

.............................................................................................................................................................

e) State how you can set up a control experiment . (1mk)

.............................................................................................................................................................

.............................................................................................................................................................

2. The diagram below represents a plant cell organelle

a) Name the organelle.

(1mk)

.............................................................................................................................................................

b) In which of the labelled parts does carbon (IV) Oxide fixation occur? (1mk)

c) Name the parts labelled A and B and state how each is adapted to its functions. (4mks)

A.....................................................................................................................................................

............................................................................................................................................

B.....................................................................................................................................................

............................................................................................................................................

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d) Explain what would have happened to the structures labelled X had the plant been kept in

darkness for 48 hours. (2mks)

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................


a) Name the structures labelled W,X, and Y. (3mks)

. X .....................................................................

Y .......................................................................

Z .......................................................................

b) State two functions of the pollen tube. (2mks)

of 744


.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

c) What happens to antipodal cells after fertilization. (1mk)

.............................................................................................................................................................

.............................................................................................................................................................

d) Name the structure labelled K and state their role. (2mks)

.............................................................................................................................................................

.............................................................................................................................................................

4. a) Name any three defects of the circulatory system in humans. (3mks)

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

b) How are leucocytes adapted to their function. (2mks)

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

c) Name the blood vessel with the highest ionic extraction of

i) Glucose

(1mk)

.............................................................................................................................................................

.............................................................................................................................................................

ii) Carbon (IV) Oxide.

(1mk)

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.............................................................................................................................................................

.............................................................................................................................................................

d) What is the importance of tissue fluid. (1mk)

.............................................................................................................................................................

.............................................................................................................................................................

5. Below is a pedigree chart showing the incidences of colour blindness trait linked to the X –

chromosome transmitted through a recessive gene. Study the diagram and answer the following

questions.

a) Gives the genotypes of person 1 and 2

1 ....................................................................

2 ...............................................................................

b) Explain why there are no male carriers for this conduction. (1mk)

.............................................................................................................................................................

.............................................................................................................................................................

6. Explain why there are more colour blind male than female in a population. (3mks)

of 744


.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

SECTION B( 40 MARKS)

Answer questions 6 ( compulsory)and either questions 7 or 8 in the spaces provided questions 8

7. The glucose level in mg per 100cm3 of blood was determined in two person Y and Z. Both had stayed

for six hours without taking food. They were fed on equal amount of glucose at the start of the

experiment .The amount of glucose in their blood was determined at intervals .The results are shown

in the table below.

Times in minutes Glucose level in blood in mg

/100cm3

Y Z

0 85 78

20 105 110

30 105 110

45 130 170

60 100 195

80 93 190

100 90 140

120 90 130

140 88 120

of 744


a) On the grid provided, plot graphs of glucose levels in blood against time on the same axes.

(7mks)

b) What was the concentration of glucose in the blood of Y and Z at the 50th minute?

(2mks)

Y .........................................................................

Z ..........................................................................

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c) Account for the level of glucose in present Y

i) During the first 45 minutes.

(2mks)

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

ii) After 45th minute to the end.

(4mks)

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

.............................................................................................................................................................

d) Account for the decrease in glucose level person Z after 60 minutes. (2mks)

.............................................................................................................................................................

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e) Low blood sugar level in harmful to the body .Explain. (3mks)

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7. a) What assumption are made when using the captured recapture method in estimating

population of animals. (5mks)

b) Describe how you would use the capture – recapture method to estimate the population of

fish in the school pond. (15mks)

8. Describe the structure and function of the various parts of the mammalian brain. (20mks)

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PROJECTION NO. 35

NAME:………………………………………………………………………………………………………INDEX …………………………..…..…..

SCHOOL:…………………………………………………………..………………SIGNATURE……………………………… DATE…………….…

231/2

BIOLOGY

PAPER 2

(Theory)

TIME: 2HOURS


1. Write your name and index number in the spaces provided.

2. Sign and write the date.

3. This paper consists of two sections. A and B.


5. In section B, answer question 6 (compulsory) and either question 7 or 8 in the spaces

provided.

For examiners use only:


A 1 9

2 8

3 7

4 8

5 8

B 6 20

7 20

8 20

TOTAL SCORE 80

of 744


SECTION A

Answer all questions in the spaces provided

1. The diagram below shows some components of a light microscope.

a) Name the parts labeled (2mrks)

K ………………………………………………………………………………………………………………

M …………………………………………………………………………………………………………….

b) State the functions of (2mrks)

P ……………………………………………………………………………………………………………………………………..

Q ……………………………………………………………………………………………………………………………………..

c) A student was viewing a prepared slide of a plant cell under high power microscope. The

features of the cell were blurred. Which one of the labelled parts of the microscope

would the student use to obtain:-

(i) a sharper outline of the features. (1mrk)

………………………………………………………………………………………………………………………………………..

(ii) Give the formula used to calculate magnification in a light microscope. (1mrk)

…………………………………………………………………………………………………………………………………………

d) A student was preparing a section of a plant cell to be viewed on a light microscope. Give

a reason for each of the following steps:-

(i)Cutting a very thin section (1mrk)

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(ii)Staining the section (1mrk)

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(iii)Putting the section in water (1mrk)

…………………………………………………………………………………………………………………………………………

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2. a) Explain what happens to excess amino acids in the liver of humans. (4mrks)

…………………………………………………………………………………………………………………………………………

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…………………………………………………………………………………………………………………………………………

b).i) What would happen if a person produced less anti-diurectic hormone? (1mrk)

…………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………

ii) What term is given to the condition described in (b) (i) above? (1mrk)

…………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………

c) State two portions of the human nephrone found only in the cortex of the kidney. (2mrk)

…………………………………………………………………………………………………………………………………………

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3. The diagram below shows a set up that was used to demonstrate fermentation.

Oil layer

Delivery tube

A B

Limewater Glucose solution and yeast suspension

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Glucose solution was boiled and oil added on top of it. The glucose solution was then allowed to

cool before adding yeast suspension.

a) Why was the glucose solution boiled before adding the yeast suspension? (1mrk)

…………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………..

b) What was the importance of cooling the glucose solution before adding the yeast

suspension? (1mrk)

…………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………..

c) What was the use of the oil in the experiment? (1mrk)

…………………………………………………………………………………………………………………………………………

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…………………………………………………………………………………………………………………………………………

d) Give two reasons why accumulation of lactic acid during vigorous exercise lead to an

increase in heart beat. (2mrks)

………………………………………………………………………………………………

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………………………………………………………………………………………………

……………………………………………………………………………………………....

e).Other than carbon (iv) oxide, name the other products of anaerobic respiration in plants.

(2mrks)

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4. In an experiment, a black mouse was mated with a brown mouse; all the off-springs were

black. The off-springs grew and were allowed to mate with one another. The total number

of (F2) generation off-springs was 96.

a) Using the letter symbols capital letter B for the gene of black colour and small b for brown

colour, Work out the genotype of the F1 generation. (3mrks)

b) From the information above, work out the following for the F2 generation.

i) Genotypic ratio. (2mrks)

………………………………………………………………………………………………

………………………………………………………………………………………………

………………………………………………………………………………………………

ii) Phenotypic ratio. (1mrk)

………………………………………………………………………………………………

……………………………………………………………………………………………..

iiii) The total number of brown mice (2mrks)

………………………………………………………………………………………………

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……………………………………………………………………………………

5. When a person’s hand accidentally touches a hot object it is quickly withdrawn, below is the

diagram showing how response occurs

B A

C

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a).Describe a reflex action that will lead to the withdrawal of hand from an object. (7mrks)

…………………………………………………………………………………………………………………………………………

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b).Name the substance responsible for the transmission of an impulse across the

synapse. (1mrk)

………………………………………………………………………………………………

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SECTION B

Answer question six and any other one question from this section in the spaces

provided.

6. (Compulsory)

An investigation was carried out between 1964 and 1973 to study the changes in fish

population in a certain lake. Four species of fish A, B, C and D were found to live in the lake. In

1965, a factory was built near the lake and was found to discharge hot water in the lake raising the

temperature from 25o c to 30o c. In 1967, sewage and industrial waste from a nearby town was

diverted into the lake. In 1969, discharge of hot water, sewage and industrial waste into the lake

was stopped. The fish populations during the period of investigation are shown in the table below.

Fish population during the period of investigation

Fish species 1964 1966 1968 1970 1971 1971 1973

A 6102 223 20 106 660 4071 7512

B 208 30 11 22 63 311 405

C 36 100 0 0 0 0 0

D 4521 272 23 27 79 400 617

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a) (i) In which year was the fish population lowest? (1mrk)

………………………………………………………………………………………………

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(ii)State the factors that might have caused the lowest fish populations during the year

you have stated in (a) (i) above. (3mrks)

………………………………………………………………………………………………

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(iii)Explain how each factor you have stated in (a) (ii) above could have brought about the

changes in the fish populations. (11mrks)

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(iii) Why did fish species C remain 0 after 1969? (1mrk)

………………………………………………………………………………………………

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b).Other than the factors stated in (a) (i) above, state other four that may affect the

population of fish in the lake. (4mrks)

………………………………………………………………………………………………

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7 (a). What is meant by the term digestion? (2mrk)

b) Describe how the mammalian small intestine is adapted to its function. (18mrks)

8. Discuss the various evidences which show that evolution has taken place. (20mrks)

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of 744


PROJECTION NO. 36

Name…………………………………………………………………………… Index No……………..

School………………………………………………………………………….. Date………………….Candidate’s

signature…………………………………..

231/2

BIOLOGY

Paper2

Time 2Hours

INSTRUCTIONS T O CANDIDATES


2.. Sign and write the date of the examination in the spaces provided .

3. Answer all the question in the spaces provided above.

4. T his paper consist of two sections A and B.

5. In section B,answer question 6 (compulsory) and either question 7 or 8 in the spaces


6. This paper consist of 12 printed pages.

7. Candidates should check the question paper to ascertain that all pages are printed as

indicated and that no questions are missing.

FOR EXAMINER USE ONLY.


A 1

2

3

4

5

08

08

08

08

08

B 6

7

8

20

20

20

TOTAL SCORE 80

of 744


1. In a garden with plants of the same species, 705 plants had red flowers while 224 had white flowers.

a) Work out the ratio of red to white flowered plants (1mark)

………………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………….

b) i) Using letter R to represent the dominant gene , work out a cross between F1

offspring and a white flowered plant. ( 4 marks)

ii) What is the genotypic ratio from the cross in b)(i) above?

Genotypic ratio (1 mark)

………………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………….

Phynotypic ratio (1 mark)

………………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………….

c) What is meant by the term allele? (1 mark)

………………………………………………………………………………………………………………………………………………………………

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2. In a physiological experiment, starch, protein, diastase and sodium chloride

were added to water and put inside a visking tubing. The visking tubing was

then placed in a water bath maintained at a temperature between 35 - 40°C.

The set up was as shown in the diagram below.

The following observations were made after the procedures indicated.

Contents in At the start of experiment After 1 hour

Visking tubing i) Solution tastes salty Solution tastes salty

ii) Visking tubing is not firm Visking tubing is firm

iii) After boiling with Benedicts

solution, solution remains blue

After boiling with Benedicts solution the solution turns brown

iv) On addition of solution

hydroxide followed by copper

sulphate solution to the solution,

the colour changes to purple

On addition of sodium hydroxide followed by coppers sulphate to the solution, the colour changes to purple

Beaker i) Water is tasteless Solution tastes sweet/salty

ii) After boiling solution with

Benedicts solution, Blue colour

remains

After boiling solution with Benedicts solution, colour turns to brown

iii) On addition to sodium hydroxide

followed by copper sulphate solution,

colour remains blue

On addition of sodium hydroxide followed by copper sulphate solution, colour remains blue

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a) Name the process by which salt moved into the water in the beaker from the visking

tubing. (l mark)

……………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………………

b) i) Name the food substance responsible for the brown colour observed after 1 hour

both in the beaker and visking tubing when solutions are boiled with benedicts solution. (l mark)

……………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………..…………………………………………………

ii) Account for the observation in (b i) above. (3 marks)

………………………………………………………………………………………………………………………………………………………………

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c) i) Name the food substance tested with sodium hydroxide followed by copper

sulphate solution(s) (1 mark)

………………………………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………………………

ii) Account for the absence of the food substance named in (c i) above in the beaker

after 1 hour. (l mark)

………………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………….

d) After one hour the visking tubing was firm. State the term used to describe this state.(1 mark)

………………………………………………………………………………………………………………………………………………………………

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3. a) Distinguish between natural and acquired immunity (l mark)

………………………………………………………………………………………………………………………………………………………………

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b) Define the term allergy (l mark)

……………………………………………………….……………………………………………………………………………………………………

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………………………………………………………………………………………………………………………………………………………..

c) The chart below shows the blood clotting mechanism

i) Name the blood cells represented by X (1mark)

………………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………..

ii) The end product of the mechanism represented by Z (1 mark)

………………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………….

d) Explain how the following environmental factors increase the rate of transpiration.

i) Temperature (2 marks)

………………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………….

ii) Humidity (1 mark)

………………………………………………………………………………………………………………………………………………………………

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iii) Atmospheric pressure (1 mark)

………………………………………………………………………………………………………………………………………………………………

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a) Name the structures labeled H and J (2 marks)

H

………………………………………………………………………………..

J ……………………………………………………………………………….

b) State how the structures labeled H, M and N are adapted to their functions. (3 marks)

H

………………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………..………………………………

M

………………………………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………………………

N

………………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………..

c) State what would happen if the structure labeled K was completely damaged. (1 mark)

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d) Name the fluid contained in structure N. (1 mark)

………………………………………………………………………………………………………………………………………………………………

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e) Apart from hearing, state the other role performed by the human ear. (1 mark)

………………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………..

5. The structures below represent specialized cells in man.

a) Identify structure X, Y and Z.

X …………………………………………………………………( l mark)

Y …………………………………………………………………(1 mark)

Z …………………………………………………………………(1 mark)

b) Give a reason for your answer for X in (a) above. (1 mark)

………………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………….

c) Give two adaptation of Z to its function. (2 marks)

………………………………………………………………………………………………………………………………………………………………

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d) What is tissue fluid? (2 marks)

………………………………………………………………………………………………………………………………………………………………

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……………………………………………………………………………………………………………………………………………………….

SECTION B(40 MARKS)

Answer question 6(Compulsory) in the spaces provided and either question 7 or 8 in

the spaces provided after question 8.

6. The table below shows the population of a housefly musca domestica which is

parasitized by wasps of species Nasonia spp. The investigation of their population growth

pattern was carried out for 70 weeks. In these experimental space and physical factors

were assumed to be limiting.

a) Using the readings in the table, plot graphs on the same axis of population growth

of organisms against time. (8 marks)

b) Account for the growth of

i) Musca domestica between 10th week — 25th week. (1 mark)

………………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………..……………….

ii) Nasonia species between 40th week –50th week. (1 mark)

………………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………….…………………………….

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c) What is the population of?

i) Nasonia spp. on the 62nd week? (1 mark)

………………………………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………………………

ii) Musca doniestica on the 4th week? (1 mark)

………………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………..

d) Bemex, another parasite of housefly was introduced into the ecosystem. Giving a

reason; what will be the effect on the population of

i) Housefly Musca domestica. (2 marks)

………………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………….

ii) Nasonia Spp. (2 marks)

………………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………….

e) In estimating the population of Musca domestica in the experiment above.

Capture-mark release recapture method was used. Describe the procedure which

was followed. (4 marks)

………………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………….

………………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………….

7. a) What is natural selection? (2 marks)

b) Describe how natural selection brings about adaptations of a species of a living

organism to its environment (18 marks)

8. a) Describe how urea is formed (5 marks)

b) Describe the path followed until it is eliminated from the body (15 marks)

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of 744


PROJECTION NO. 37

NAME:……………………………………………………………………………………….… INDEX NO:…………………………

SCHOOL:…………………………………………………………………………………..….. DATE:……………………………….

SIGN:……………………………….

231/2

BIOLOGY

PAPER 2

(THEORY)

TIME: 2 HOURS


1. Answer ALL questions in section A in the spaces provided.

2. In section B answer question 6 (compulsory) and either question 7 or 8 on the foolscap provided.

3. Candidates will be penalized for not following instructions in this paper carefully.

4 All workings must be clearly shown where necessary.



A 1

2

3

4

5

08

08

08

08

08

B 6

7

8

TOTAL 80

of 744



1. The figure below illustrate a response in plants.

(a) State the type of response illustrated (1mk)

………………………………………………………………………………………………………………………………………………………...

(b) Explain how the response occurs. (4mks)

…………………………………………………………………………………………………………………………………………………………..

…………………………………………………………………………………………………………………………………………………………..

………………………………………………………………………………………………………………………………..………………………..

…………………………………………………………………………………………………………………………………………………………..

(c) State two importance of phototactic response in termites. (2mks)

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(d) State hormone used in agriculture that breaks breaking seed dormancy. (1mk)

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2. (a) (i) Define sex linkage. (1mk)

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(ii) In a marriage of Jane and Otieno who are both normal for hemophiliac condition,

gave birth to four children Susan, Grace, Tom and Peter. Tom the second born

child was hemophilic. Later in life Tom married Alice who was normal. Their first

born child was hemophiliac. (Let H represent gene for normal condition.)

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(b) (i) What was the genotype of Alice. (1mk)

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(ii) Work out the phenotypic ratio of F2. (5mks)

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(c) How does the police force use knowledge on genetics. (1mk)

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(d) What is the name given to points of contact in a pair of homologous

chromosomes. (1mk)

………………………………………………………………………………………………………………………..……………………………..

3. A student observed feeding relationship while on a tour in a coastal Island.

Eagles feed on small fish.

Small fish feed on sea grass

Insect larvae and molluscs feed on sea grass.

Insect larvae fed on by small fish, while crabs feed on insect larvae and molluscs.

(a) From the above information , construct a food web. (3mks)

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(b) In which trophic level is small fish found. (1mk)

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(c) Extract a food chain where the Eagle is a tertiary consumer. (1mk)

…………………………………………………………………………………………………………………………………………………………

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(d) Suppose all the crabs were poisoned, what would be the immediate effect in the

ecosystem. Give a reason. (1mk)

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(e) Give a reason why pyramid of biomass is a better representation of energy flow in an

eco system than pyramid of numbers. (1mk)

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4. A student wanted to observe human red blood cells under a light microscope. He put l0ml of

solution X,Y and Z in three boiling test tubes. The solutions were of different concentration .In

each of the test tubes he put three drops of blood sample. The experiment was left to stand for 30

minutes. He placed one drop of solution X on glass slide and observed under the microscope.

The same procedure was repeated for solutions Y and Z.

He made the following observation.

Solution Observation

X Normal Cells

Y Wrinkled Cells

Z No cells observed

(a) What was the physiological process observed. (1mk)

……………………………………………………………………………………………………………………………………………………………

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(b) Explain why red blood cells observed in solution Y were wrinkled. (3mks)

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(c) A 3cm long piece of kale (sukuma wiki) stem was cut halfway along its length as

shown below.

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(i) If the piece was placed in solution Z for 30 minutes, its shape changed . Using a pencil

draw a diagram in the space provided to show the expected change. (1mk)

(ii) Explain the results obtained in C(i) above. (3mks)

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5. An experiment was set up as shown below.

(a) A student blew air in and out through point X. Using arrows indicate on the diagram how

air gets in and out of the set up. (2mks)

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(b) (i) In which of the test tube would lime water turn milky first. (1mk)

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(ii) Give a reason. (1mk)

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(c) What is the effect of lactic acid in the thigh muscles of an athlete after a short fast race.

(2mks)

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(d) Identify the type of muscle in human being where formation and effect of lactic acid is

not felt. (1mk)

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(e) What is the biological significance of boiling milk /ultra heat treated milk. (1mk)

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SECTION B

COMPULSORY QUESTIONS.

6. A man was starved for 24hours.He was then served with a balanced diet after which the

concentration of glucose in the hepatic and hepatic portal veins were determined at interval of 1

hour for the next 8 hours after the meal.

The results were as shown in the graph below.

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(a) From the graph state the normal concentration of glucose in man. (1mk)

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(b) Determine the concentration of glucose after 2 ½ hrs. (2mks)

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(c) Calculate the rate of glucose between 1 - 2 hours in hepatic portal vein. (2mks)

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(d) Account for the blood sugar level in hepatic portal vein and hepatic vein between; (4mks)

(i) 0- 1hour

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(ii) 2 - 4 hours. (6mks)

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(e) A patient was found to produce urine that tasted sweet. Name the disease he was likely

to be suffering from. (1mk)

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(f) How would you test for the disease in your school laboratory. (3mks)

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(g) What advice would you give to a patient whose blood contains abnormal high

levels of urea. (1mk)

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…………………………………………………………………………………………………………………………………………………………..

ANSWER EITHER QUESTION 7 OR 8 IN THE SPACES PROVIDED AFTER THE QUESTIONS.

7. Describe how human skin is adapted to its function. (20mks)

8. (a) Describe the adaptation of floating water lily leaf to its photosynthetic function. (10mks)

(b) Describe the activities that take place in the chloroplast of growing plants. (10mks)

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PROJECTION NO. 38

Name…………………………………………………………………………………. Index No…………………/…….

School…………………………………………………………………………….… Date ………………………….…

Candidate’s Signature………………………

231/2

BIOLOGY

(THEORY)

Paper 2

JULY / AUGUST 2012

Time: 2 Hours


• This paper consists of two sections A and B.

• Answer ALL questions in section A

• Answer question 6 (compulsory) and either question 7 or 8 in section B.

For Examiner’s Use Only Section Question Maximum score Candidate’s score

A 1

2

3

4

5

8

8

8

8

8

B 6

7

8

20

20

20

Total Marks 80

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1. During an ecological study, students collected and marked 120 ants and released them. After

48 hours, the students captured another 90 ants, 20 of which had been marked previously.

(a) How many ants were there in the compound? Show your working. (3mks)

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(b) What are the limitations of this method in sampling animal populations. (4mks)

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(c) State two other methods which could be used to determine the population. (1mk)

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2. In an experiment to investigate the action of pepsin on egg albumen, equal amount of

paper were added to equal amount of egg albumen in different test –tubes. The test-tubes

were placed in water bath at different temperature. The graph below shows the time taken

for the enzymes to digest protein at each temperature.

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(a) What is the optimum temperature for enzymes? (1mk)

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(b) Account for the time taken to digest egg albumen at 600C. (2mks)

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(c) With reasons name the form in which the enzyme pepsin is secreted. (2mks)

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(d) State three other factors that affect enzyme controlled reactions. (3mks)

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3. The chart below represents the results of successive cross, starting with red-flowered

Plants and write flowed plants and in which both plants are pure breeding.

Parental genotype: Red Flowers x White Flowers

First filial generation

Selfed

Second filial generation

3 Red flowers : 1 White flower

(a) What are the parental genotypes? Use letter R to represent the gene for Red flower

colour and r for white colour. (2mks)

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…………………………………………………………………………………………………………………………………………………….

(b) (i) What was the colour of the flowers in the first filial generation? (1mk)

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(ii) Give a reason for your answer (1mk)

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…………………………………………………………………………………………………………………………………………………….

(c) If 480 red flowered plants were obtained in the second filial generation, how

Many F2 plants had white flowers? Show your working. (4mks)

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4. (a) State the meaning of apical dominance in plants (1mk)

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(b) Name the hormone associated with apical dominance. (1mk)

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(c) What is the importance of apical dominance? (1mk)

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(d) Briefly describe the effects of the following plant growth hormones

(i) Gibberellins (2mks)

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(ii) Abscisic Acid (3mks)

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5. The diagram below represents a transverse section of a leaf.

(a) (i) State the habitat of the plant from which the leaf was obtained. (1mks)

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(ii) Give two reasons for your answer in (a) (i) above. (2mks)

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(b) How does the part labelled B adapt the plant to its habitat (1mk)

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(c) Smokers are always at a high risk of suffering from respiratory infections.

Explain (3mks)

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(d) What structures are used for gaseous exchange in plants found in marine water? (1mk)

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Answer question 6 (compulsory) in the spaces provided and either


6. Carbohydrates used during respiration and those formed during photosynthesis by a

certain plant was measured over a period of 24 hours at an interval of 3 hours

Time of day 12AM 3AM 6AM 9AM 12PM 3PM 6PM 9PM 11PM

Carbohydrates

formed during

photosynthesis (mg)

0 0 5 30 60 30 5 0 0

Carbohydrates used

during respiration

(mg)

10 10 10 10 10 10 10 10 10

Using the same axes,

(a) Plot a graph of carbohydrate formed during photosynthesis and carbohydrate used during

respiration against time. (7mks)

(b) Calculate the net carbohydrate formed by the plant. (2mks)

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(c) At what time of the day do the light compensation points occur? (2mks)

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(d) Account for the shape of graph on carbohydrates.

(i) Between 12.00a.m and 3a.m. (2mks)

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(ii) Between 3.00a.m to 12.00 noon. (2mks)

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(e) How could foggy weather influence the net amount of carbohydrates formed

over the 24 hour period? (1mk)

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(f) Give other external factors apart from temperature and light intensity that

influence the rate of photosynthesis. (2mks)

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(g) In which form are carbohydrates stored in

(i) Plant bodies. (1mks)

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(ii) Fungi (1mk)

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7. (a) Define natural selection. (2mks)

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(b) Natural selection brings about adaptation of a species to the environment.

Discuss. (18mks)

8. Discuss the adaptations of seeds and fruits to dispersal. (20mks)

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PROJECTION NO. 39

Name……………………………………………………………. Index No……………………………..

School…………………………………………………………… Candidate’s sign…………………….

Date………………………………….

231/2

BIOLOGY

Paper 2

(THEORY)

2 Hours

INSTRUCTIONS TO CANDIDATES.

1. write your name and admission number in the spaces provided 2. Sign and write the date of examination in the spaces provided above 3. this paper consist of TWO section A and B 4. Answer ALL the questions in section A in the spaces provided 5. In section B answer question 6 (compulsory and either question 7 or 8 in the spaces provided

after question 8. 6.


SECTION QUESTION MAX.SCORE CANDIDATES SCORE

A 1

2

3

4

5

8

8

8

8

8

B 6

7

8

20

20

20

TOTAL 80

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SECTION A (4OMKS)


1. ( a) Define

i) Osmosis (lmk)

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ii) Haemolysis (lmk)

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(b) State the role of active transport in plants. (2mks)

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(c) Why is oxygen important in the process of active transport? (lmk)

………………………………………………………………………………………………………………………………………………………………

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(d) State three properties of the cell membrane (3mks)

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.…………………………………………………………………………………………………………………………………………………………

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2. In a family with four children, three were found to have normal skin pigmentation while one was an

albino. Using letter A to represent gene for normal skin pigmentation and a to represent the gene for

albinism.

(a) What are the genotypes of the parents? (2mks)

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(b) Work out the genotypes of the normal pigmented children and the albino child (5mks)

(c) What is the probability that the fifth child will be an albino? (lmk)

……………………………………………………………………………………………………………………………………………………………

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3. The diagram below represents a food web in a terrestrial ecosystem.

(a) Which organism has the highest number of preys (lmk)

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(b) Construct food chains with snakes as tertiary consumers (2mks)

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(c) State the trophic level occupied by hawks in the food chains constructed in b) above (lmk)

……………………………………………………………………………………………………………………………………………………………

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(d) Describe how capture — recapture method can be used in estimating the population of

fishes in a lake. (4mks)

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4. (a) Differentiate between the mode of fertilization in higher plants and in mammals (2mks)

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(b) Explain the role of the following hormones in the female menstrual cycle

(i) Oestrogen (2mks)

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(ii) Luteinizing hormone (2mks)

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(c) Give two functions of the placenta during pregnancy (2mks)

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5. In an experiment to investigate an aspect of digestion, two test tubes P and Q were set up as show in

the diagram below.

The test tubes were left in the bath for 30 minutes. The content of each test tube was then tested for

starch using iodine solution.

(a) What was the aim of experiment? (lmk)

……………………………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………………………..

(b) What results were expected in test tube P and Q (2mks)

P………………………………………………………………………………………………………………………………………………………..

Q……………………………………………………………………………………………………………………………………………………….

(c) Account for the results you have given in b above in test tube P and Q (2mks)

P

………………………………………………………………………………………………………………………………………………………………

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Q

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(d) Why was the set up left at 37°C (1 mk)

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(e) Name the carbohydrate stored in (2mks)

i. Mammalian liver

……………………………………………………………………………………………………………………………………………………………

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ii. Potato tuber

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SECTION B

Answer question 6 (Compulsory) and either question 7 or 8

6. Two sets of a pea seeds were germinated, set A was placed in normal daylight conditions in the

laboratory while set B was placed in a dark cupboard. Starting a few days later the shoots lengths

were measured twice daily and their mean lengths recorded as shown in the table below.

(a) Using suitable scale draw the graphs of the mean lengths in set A and B against time.

(b) From the graph state the mean shoot length of each set of seedling at the 66th hour (2mks)

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(c) Account for the difference of curve B and A (3 mks)

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(d) Explain what would happen to set up B if it were allowed to continue to grow under

conditions of darkness (4mks)

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(e) State three external conditions which should be constant for both set ups (3mks)

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7. (a) What is reflex action? (lmk)

(b) Describe what happens in the nervous system of a person who withdraws a finger from a

very hot object. (14mks)

(c) Explain what happens to a young growing seedling when exposed to unidirectional

source of light. (5mks)

8. (a) Outline the characteristics of the meristematic tissues. (5mks)

(b) Explain how different meristematic tissues contribute to growth higher plants. (l5mks)

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PROJECTION NO. 40

Name……………………………………………………………………………………………………….… Index No……………..

School……………………………………………………………………………………………………….. Date………………….

Candidate’s signature…………………………………..

231/2

BIOLOGY

Paper 2

Time 2Hours













A 1

2

3

4

5

08

08

08

08

08

B 6

7

8

20

20

20

TOTAL SCORE 80

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Answer All questions in this section

1. Two herbivorous mammalian species were introduced into an ecosystem at the same time

and iin equal numbers. The graph below represents their populations during the first seven

years. Study the graph and answer the questions that follow.

a) i) Which species has a better competitive ability? (1 mark)

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ii) Give reason for your answer (l mark)

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b) Account for the shape of the curve of species A between

i) One year and three years (2 marks)

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ii) Three years and seven year (2 marks)

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c) A natural predator for species A was introduced into the ecosystem. With a reason state

how the population of each species will be affected (2 marks)

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2 The chart below represents the result of successive crosses, staring with red flowered

plants and white flowered plants in which both plants are pure breeding

a) What were parental genotype ? Use letter R to represent the gene for red color and

r for white color ( l mark)

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b) i) What was the colour of the flowers in the first filial generation?( l mark)

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ii) Give a reason for your answer in b (i) above (l mark)

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c) lf 480 red flowered plants were obtained in the second filial generation, how many

F2 plants had white flowers? Show your working (5 marks)

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3. A form 1 student placed a red blood cell in a solution and made an observation as follows.

Start of experiment/ end of experiment

a) i) In what solution was the red blood cell paced? (l mark)

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ii) Explain the observation above (2 marks).

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b) If the red blood cell was replaced by a plant cell what would be the observation

(2 marks)

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c) Why don’t the red blood cell undergo the same changes as above while in the

body. (3 marks)

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4. The figure shows changes that take place during menstrual cycle in human

a) Name the hormone whose concentrations are represented by curves F and G

(2 marks)

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b) State the effects of the hormones named in (a) above on the lining of the uterus

(2 marks)

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c) i) Name the hormone which is released by the pituitary gland in high

concentrationon the 14th day of the menstrual cycle (l mark)

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ii) State two functions of the hormone named in (c) (i) above (2 marks)

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. ..................................................................................................................................................................

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d) State the fertile period during the menstrual cycle ( 1 mark)

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5. The diagram below represents a bone obtained from a mammal

a) Name the bone ( 1 mark)

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b) Name the:

i) Bone which articulate with the bone named in (a) above at the cavity

labeled K; ( 1 mark)

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ii) Joint formed by the two bones (1 mark)

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c) State the function of the part labeled J

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d) Explain how the pelvic girdle is adopted to its function (4 marks)

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Section B

Answer question six in the spaces provided and either question 7 or 8 in the spaces provided

after question8

6. An experiment was carried out to investigate the nutritional value of two dry powder

animals feeds X and Y over a period of six months. Twenty 5 month’s old castrated goats

were use. The goats were divided into two equal groups A and B.

The animal’s in group A were fed on feed X throughout the experiment while those of

group B were fed on feed Y.

The feeds were supplemented with dry hay and water. The average body weight of each

group of goats and the weight of the dry powder feeds were determined and recorded each

month. The faeces produced by each group was dried and weighed and the average dry

faecal output per month was also recorded. The results are as shown below.

GROUP A GROUP B

Months since

commencement

of the

experiment

Average

total

weight of

goats(Kg)

Average

weight

of total

feed(Kg)

Average

monthly

dry faecal

output(Kg)

Average

total

weight of

goats(Kg)

Average

weight

of total

feed(Kg)

Average

monthly

dry faecal

output(Kg)

0 20.4 26.7 10.5 20.5 35.4 16.5

1 22.5 27.5 10.7 19.5 34.3 17.7

2 24.5 25.8 10.3 19.0 35.2 17.2

3 26.3 18.5 8.8 18.5 36.1 17.5

4 28.0 16.6 7.2 17.1 36.0 16.9

5 29.4 16.3 6.0 16.3 35.8 16.8

6 29.5 16.1 5.6 15.6 35.5 16.6

a) i) What is the relationship between the amount of feed and the faecal output

(2 marks)

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ii) Work out the average increase in weight for the animal’s in group A during:

The first four months

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The last two months

. ...................................................................................................................................................

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(4 marks)

iii) Account for the average increase weight in goats in group A during:


....................................................................................................................................................

....................................................................................................................................................

....................................................................................................................................................

The last two months

....................................................................................................................................................

....................................................................................................................................................

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(4 marks)

iv) Which of the two feeds is more nutritious? Give reason for your answer

(2 marks)

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b) Explain the digestion of lipids in humans (8 marks)

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7 a) Describe how semicircular canals perform their functions (8 marks)

b) Describe how the cervical, lumbar and sacral vertebrae are suited to their functions

(l2 marks)

8 a) State four characteristics of gaseous exchange surfaces. (4 marks)

b) Explain the theories for opening and closing of the stomata (16 marks)

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....................................................................................................................................................

PROJECTION NO. 41

Name: …………………………………………………………… Index no ……..…...................................

School: ……………………………………………………....…. Candidate’s sign ……………………....

Date: ……………………………………………………………

231/2

BIOLOGY

PAPER 2

TIME: 2 HOURS


• Write your name and index number in the spaces provided.


• In section B answer questions 6 (compulsory) and either question 7 or 8 in the spaces provided

For Examiner’s Use Only:

SECTION QUESTIONS MAXIMUM SCORE CANDIDATES SCORE

A 1 8

2 8

3 8

4 8

5 8

B 6 20

7 20

8 20

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TOTAL 80

1. The diagram below represents bones at a joint found in the forelimb of a mammal.

a) Name the bones labeled A,C and D. (3mks)

A ………………………………………..……………………………………………………………………………………………………

C……………………………………………………………………………………………………………………………………………….

D……………………………………………………………………………………………………………………………………………….

b) Name the structure at the knee that performs the same function as the structure labelled E. (1mk)

…………………………………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………………………………

c) State one difference between the joint between bones A and G and that between bones G and C (1mk)

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d) Name the structure that joins bones and muscles. (1mk)

……………………………………………………………………………………………………………….………………………………………………

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e) Explain how the muscles F and B bring about stretching and flexing of the arm. (2mks)

………………………………………………………………………………………………………………………………………………………………

A

B F

C

E

G

D

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………………………………………………………………………………………………………………………………………………………..……

2 a) Define the following

(i) Photosynthesis (1mk)

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(ii) Chemosynthesis. (1mk)

…………………………………………………………………………………………………………………………………………………………………

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b) Study the diagram below and answer the questions that follow.

(i) What is destarching? (1mk)

…………………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………….………………………..

(ii) Giving reasons state the expected results when leaf A and Leaf B are tested for starch.

Leaf A ……………………………………………………………………………………………………… (1mk)

Reason (1mk)

……………………………………………………………………………………………………………………………………………………………

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Leaf A

Sodium hydroxide pellets

Flask

Cork

Leaf B

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Leaf B……………………………………………………………………………………………………. (1mk)

Reason (1mk)

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3. The diagram below show a respiratory structure of a bony fish

a) Name the parts labelled A,B and C (3mks)

A …………………………………………………………………………………………………………………………………..……………….

B …………………………………………………………………………………………………………………………………………………….

C …………………………………………………………………………………………………………………………………..…………………

b) What is the advantage of counter-current flow system in fish over the parallel flow? (2mks)

……………………………………………………………………………………………………………………………………………….………………

……………………………………………………………………………………………………………………………………………………..……….

c) How is the part labeled A adapted to its function. (3mks)

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………………………………………………………………………………………………………………………………………………………………

A B

C

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4. a) Distinguish between biotic and abiotic factors in an ecosystem. (2mks)

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b) Describe how capture and recapture method can be used to estimate the population of a certain

insect in an habitat. 4mks)

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c) Name the organisms through which energy from the sun enters the food web. (1mk)

……………………………………………………………………………………………………………………………………………………………….

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d) Give two reasons why primary productivity in the aquatic ecosystem decreases with depth? (2mks)

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5. a) What is linkage. (1mk)

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b) Name two sex-linked traits associated with the Y-chromosome in human beings. (2mks)

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c) The inheritance of colour vision is a sex-linked trait in man. The gene for normal colour vision is

dominant . A marriage between a woman who is homozygous for normal colour vision and a colour

blind man resulted in all the offsprings with the normal colour vision.

Work out the Phenotypic ratio in a marriage between one of the daughters and a colour blind man. Use

N to represent the gene for normal colour vision.

(5mks)

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SECTION B (40MARKS)

Answer questions 6(compulsory) and either questions 7 or 8

6. The table below show the relative numbers of three main species of organisms in a pond.

Depth in meters 0.00 0.50 0.75 1.00 1.25 1.75 2.00 2.50 3.00

Number of

organisms in

thousands

R 0 0 0 0 8 25 34 15 0

Q 20 160 190 165 115 10 0 0 0

P 10 25 40 53 45 18 5 2 0

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a) Using the same axes, draw the graphs to show number of organisms against depth. (8mks)

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b) Which of the three species is widely distributed within the pond? (1mk)

………………………………………………………………………………………………………………………………………………………………..

………………………………………………………………………………………………………………………………………………………………..

b) Giving a reason for your answer, which of the species is a producer?

Producer…………………………………………..…………………………………………………… (1mk)

Reason (1mk)

…………………………………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………………………………

d) At which depth are the population of the species the same? (1mk)

………………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………………….

e) Giving a reason for your answer which of the species is a primary and secondary consumer?(4mks)

Primary consumer

………………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………………..

Reason

……………………………………………………………………………………………………………………………………………………………..

……………………………………………………………………………………………………………………………………….……………………

Secondary consumer

…………………………………………………………………………………………………………………………………………………………….

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Reason

……………………………………………………………………………………………………………………………….……………………………..

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(f) Explain two ways in which the following are adapted to their functions.

(i) Palisade layer (2mks)

………………………………………………………………………………………………………………………………………………………………

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(ii) Cuticle (2mks)

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7. Explain how the mammalian heart is adapted to perform its function. (20mks)

8. Discuss the various evidences of organic evolution. (20 mks)

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PROJECTION NO. 42

Name: …………………………………………………………… Index no ……..…...................................


Date: ……………………………………………………………

231/2

BIOLOGY

THEORY

PAPER 2

TIME: 2 HOURS







A 1 8

2 8

3 8

4 8

5 8

B 6 20

7 20

8 20

TOTAL 80

of 744


SECTION A (40MARKS)


1. In human beigns the phenotypes and genotypes with respect to the condition of sickle anaemia

are as follows

a) Carry out a genetic cross to predict the outcome of a man and a woman with the sickle

cell trait. (4mks)

b) What are the phenotypic and genotypic ratios. (2mks)

…………………………………………………………………………………………………………………………………………………………………..

…………………………………………………………………………………………………………………………………………………………………..

…………………………………………………………………………………………………………………………………………………………………….

c) Name the two possible sets of chromosomes that can be found in a normal cell. (2mks)

………………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………………………………

Phenotype Genotype

Unaffected

Sickle cell trait

Sickle cell anaemia

SS

Ss

ss

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2. The diagram below represents a unit of gaseous exchange in man. Study it carefully and answer the


a) Name the blood vessel that brings blood to the lungs and the vessel which takes blood away from

the lungs. (2mks)

……………………………………………………………………………………………………………………………………………….………………

………………………………………………………………………………………………………………………………………………………………..

……………………………………………………………………………………………………………………………………………………………….

b) Name the structure above. (1mk)

…………………………………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………………………………..

c) Label A and E. (2mks)

A……………………………………………………………………………………………………………………………….

E……………………………………………………………………………………………………………………………….

d) In what form is carbon (IV) oxide transported in structure labeled E. (1mk)

……………………………………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………………………………….

e) Name the gas G. (1mk)

……………………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………………………..

A

D

G H G E

B

• •

•

•

• •

•

•

•

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3. Gastrin is a hormone produced by mammals.

(a) (i) Where is the hormone produced? (1mk)

………………………………………………………………………………………………………………….…………………………………………………

…………………………………………………………………………………………………………………………………………………………………….

(ii) What is the function of gastrin? (1mk)

…………………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………………….

(b) What stimulateds the production of gastrin. (1mk)

……………………………………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………………………………….

(c) The diagram below shows part of the human intestine.

(i) Identify the parts labeled A and B (1mk)

A…………………………………………………………………………………………………………………………………………..

B…………………………………………………………………………………………………………………………………………. (1mk)

(ii) To which circulatory system does the part labeled B belong. (1mk)

……………………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………………………

d) State any two adaptations of the human large intestine to its function. (2mks)

……………………………………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………………………………….

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4 The diagram below represents part of a xylem tissue.

a) (i) Name the parts labeled P and Q (2mks)

P ……………………………………………………………………………………………………………………………………………..

Q ……………………………………………………………………………………………………………………………….…………….

(ii) Give the function of the part labeled P. (1mks)

…………………………………………………………………………………………………………………………………………………………..

…………………………………………………………………………………………………………………………………………………………..

b) State the function of the phloem tissue. (1mk)

…………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………..

c) (i) State how the functioning of the phloem tissue is affected if the companion cell is destroyed. (1mk)

………………………………………………………………………………………………………………………………………………….………

…………………………………………………………………………………………………………………………………………………………

(ii) Give a reason for your answer. (1mk)

…………………………………………………………………………………………………………………………………………………..………

………………………………………………………………………………………………………………………………………………………….

d) State any two structural differences between phloem and xylem tissues. (2mks).

…………………………………………………………………………………………………………………………………………………………………..

………………………………………………………………………………………………………………………………………………………………….

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5 The diagram below represents a food web from Lake Nakuru national park.

a) With a reason, identify the organism with the largest biomass. (2mks)

…………………………………………………………………………………………………………………………………………………………………..

………………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………………..

b) From the food web isolate a food chain ending with snakes as tertiary consumer. (1mk)

…………………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………………..

c) (i) Name any two organisms not shown in the food web but would be present in the

ecosystem. (1mk)

…………………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………………….

………………………………………………………………………………………………………………………………………………….………………….

(ii) What is the role of the organisms stated in (i) above in the ecosystem. (2mks)

……………………………………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………………………………..

………………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………………

Green plants

Insects

Rats

Squirel

Birds Snakes

Rabbits Deers

Leopards

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d) From the food web, snakes and leopards feed on rabbits. What name is given to this kind of

competition. (1mk)

…………………………………………………………………………………………………………………………………………………………………..

………………………………………………………………………………………………………………………………………………………….………

e) Name an organisms that may be both secondary and tertiary consumer. (1mk)

……………………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………………………

SECTION B (40MARKS)

Answer questions 6(compulsory) and either questions 7 or 8

6. In an experiment to determine the effect of exercise on the concentration of lactic acid in blood, the

following data was obtained. Study the data and use it to answer the questions that follow.

The lactic acid concentration was measured before, during and after the exercise.

a) Using a suitable scale, plot a graph of the concentration of lactic acid against time. (6mks

b) From the graph you have drawn determine

(i) The period of exercise . Explain. (2mks)

……………………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………………………

(ii) The time when oxygen debt occurred Explain. (2mks)

……………………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………………..……

…………………………………………………………………………………………………………………………………………….………………………

Time minutes 0 10 20 25 30 40 50 60 70 80 90 100

Lactic acid conc.

(arbituary units)

0.5 0.5 5 13 12 8 6 4 3 2 1 0.9

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(iii) The duration it took to pay back the oxygen debt. Explain (2mks)

………………………………………………………………………………………………………………………………………………………………..

………………………………………………………………………………………………………………………………………………………………..

……………………………………………………………………………………………………………………………………………………………….

c) On the same set of axes plot a hypothetical curve for oxygen intake during the experiment period

of 90 minutes. (2mks)

d) Why does lactic acid level usually continue to rise in the blood after exercise ceases. (2mks)

……………………………………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………………………………..

e) Suggest the two importance of anaerobic respiration to animals. (2mks)

…………………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………………….

d) What is oxygen debt? (2mks)

……………………………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………………………..

…………………………………………………………………………………………………………………………………………………………………………

7. What is the role of the liver in the maintance of a constant level of materials in the body. (20mks)

8 (a) What is organic evolution? (2mks)

(b) Distinguish between homologous and analogous structure. (2mks

(c) How does natural selection bring about adaptation of species to its environment. (16mks)

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PROJECTION NO. 43

Name: …………………………………………………………… Index no ……..…...................................


Date: ……………………………………………………………

231/2

BIOLOGY

PAPER 2

TIME: 2 HOURS






SECTION QUESTIONS MAXIMUM

SCORE

CANDIDATES

SCORE

A 1- 5 40

B 6 20

7 or 8 20

TOTAL 80

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Answer all the Questions by filling in the spaces provided.

1. The drawing below represents a mature bread mould (rhizopus). Study it and answer the questions

which follow

a) Name the structures labeled A, B, and C. (3mks)

A……………………………………………………………………………………………………………………………………………………

B …………………………………………………………………………………………………………………………………………………

C………………………………………………………………………………………………………………………………………………..

b) Identify the type of asexual reproduction represented in the diagram. (1mk)

………………………………………………………………………………………………………………………………………………….

………………………………………………………………………………………………………………………………………………..

c) Give one function of structure C. (1mk)

…………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………….

d) i) Define the term fertilization. (1mk)

…………………………………………………………………………………………………………………………………………………..

…………………………………………………………………………………………………………………………………..………………

ii) Compare an ovum cell and a zygote. (2mks)

…………………………………………………………………………………………………………………………….……………………

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2. During a laboratory investigation, a scientist extracted gastric juice from the mammalian stomach. He

used it to carry out tests on a food sample B which was suspected to contain proteins. He divided the

food sample B into three portions and treated them as below.

I. On the 1st portion of B, he added Gastric juice and mixed them thoroughly before adding sodium

hydroxide followed with copper (II) sulphate drop by drop.

II. On the 2nd portion of B, he added boiled gastric juice and mixed them thoroughly before adding

sodium hydroxide followed with copper (II) sulphate drop by drop.

III. On the 3rd portion of B, he added Gastric juice, sodium bi-carbonate and mixed them thoroughly

before adding sodium hydroxide followed with copper (II) sulphate drop by drop.

a) State the observations he made in each set up. (3mks)

- 1st portion

………………………………………………………………………………………………………………………………………………..………………

……………………………………………………………………………………………………………………………………………..………………….

- 2nd portion

…………………………………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………………………………

- 3rd portion

…………………………………………………………………………………………………………………………………………….…………………

………………………………………………………………………………………………………………………………………………………………

b) Why was the experiment on the 1st portion included in the tests? (1mk)

…………………………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………………….……

c) Name the property of the chemical being investigated in these tests. (1mk)

………………………………………………………………………………………………………………………………………..……………………

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d) Account for the observations made in 2 (a) above. (3mks)

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……………………………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………………………….

3. The diagram below illustrates circulation in certain organs of the mammalian body.

a) Identify the blood vessels represented by A, B and C. (3mks)

A………………………………………………………………………………………………………………………..………………………….

B……………………………………………………………………………………………………………………………..……………………

C………………………………………………………………………………………………………………………………..………………..

b) Explain why blood from the small intestines goes to the liver before it goes to any

other organ of the body. (2mks)

…………………………………………………………………………………………………………………………………….……………………

…………………………………………………………………………………………………………………………………………………………

c) Compare the blood in vessels B and C. (1mk)

…………………………………………………………………………………………………………………………………………………….……

………………………………………………………………………………………………………………………………………………………….

Small Intestines

Heart

Liver

B

C

A

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d) Outline how a glucose molecule in vessel A finally reaches the heart. (2mks)

………………………………………………………………………………………………………………………..……………………………………

…………………………………………………………………………………………………………………………………….………………………

……………………………………………………………………………………………………………………………………………………………

4. The figure below shows a germinating seedling.

a) On the diagram, label the parts labeled A to D. (2mks)

…………………..……………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………..

………………………………………………………………………………………………………………………………………………………..

………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………

b) State two functions of the part labeled B. (2mks)

……………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………………..

c) Name the type of germination shown by the diagram. (1mk.)

………………………………………………………………………………………………………………………………………………………….

………………………………………………………………………………………………………………………………………………………….

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d) Explain two functions carried out by enzymes during the process of germination. (2mks)

…………………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………………..

e) Give a reason why the radical emerges first during germination. (l mk)

………………………………………………………………………………………………………………………………………………………………..

………………………………………………………………………………………………………………………………………………………………..

5 a) The gene that controls colorblindness is sex-linked. What does this mean? (1mk)

………………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………………………….

b) A colorblind son was born to parents who did not show any external signs of this disorder.

I. State the genotype of the parents. (1mk)

…………………………………………………………………………………………………………………………………………………..…………

………………………………………………………………………………………………………………………………………………………………

II. With the aid of a punnet square, show how a colorblind son came about. (4mks)

c) Distinguish between incomplete dominance and co-dominance as used in genetics. (2mks)

…………………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………………..

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Answer question 6 and either question 7 or question 8.

6. The table below shows how the internal temperature two animals X and Y varied with the external

temperature. The temperature was measured regularly and recorded for 12 hours in a day. Study the

table and answer the questions that follow.

a) Using the same grid, draw graphs of external temperature, and internal temperature of animals X and Y

(Y-axes) against time (X-axes). (7mks)

b) Account for the variation of internal and external temperatures for the animals X and Y. (2mks)

X

…….........................................................................................................................................................................

………………………………………………………………………………………………………………………………………………………………………..

Y

……………………………………………………………………………………….……………………………………………………………………………..

………………………………………………………………………………………………………………………………………………………………………….

c) Identify the classification of organisms whose internal temperature varies as X and Y (2mks)

X…………………………………………………………………………………………………………………..……………………………………..………..

Y…………………………………………………………………………………………………………………………………………………………………..

Time 6.0am 7.0am 8.0am 9.0a

m

I0.0am 11.0am 12.0 1.0pm 2.0pm 3.0pm 4.0pm 5.0pm

External

temp. (°c)

2 10 15 18 24 30 35 37 39 28 25 20

Internal

temp.(°c)

X 2 9 14 17.5 23 30 34 37 38 29 26 20

Internal

temp.(°c)

Y 36 37 38 37 36 37 38 37 36 37 38 37

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d) Explain two ways used by organism Y to make its internal temperature vary as shown despite of

changes in external temperature. (4mks)

……………………………………………………………………………………………………………….………………………………………

………………………………………………………………………………………………………………………………………..………………

………………………………………………………………………………………………………………………………………………………..

…………………………………………………………………………………………………………………………………………………………

e) Fish is one of the organisms which get adapted to live under varying external temperatures. Apart from being adapted to live under varying external temperatures, describe five other modifications

that enable it to live in water successfully. (5mks)

………………………………………………………………………………………………………………………………………………………..……….

…………………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………………..

………………………………………………………………………………………………………………………………………………………………..

………………………………………………………………………………………………………………………………………………………………..

…………………………………………………………………………………………………………………………………………………………………

7. a) Explain the factors that affect the rate of transpiration in plants. (l2mks)

b) Describe different ways in which plants respond to different stimuli. (8mks)

8 a) Give the functions of the skin in organisms. (6mks)

b) How is the mammalian skin modified to enable it perform its functions? (l4mks)

…………………………………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………………..

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PROJECTION NO. 44

Name: ……………………………………………………………………...…Candidate’s Signature ………..…………………………..…..

School: …………………………………………………….………………..……Date: ………………………………………………..………………

231/2

BIOLOGY

PAPER 2

(THEORY)

TIME: 2 HOURS







question 8.



A 1

2

3

4

5

8

8

8

8

8

B 6

7 or

8

20

20

20

TOTAL SCORE 80

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SECTION A


1. In a plant breeding experiment, tall plants were cloned with dwarf plants. They produced 93 tall

plants and 94 dwarf plants.

(a) State the phenotypic ratio of the offspring. (1mk)

…………………………………………………………………………………………………………………………………………………….…

………………………………………………………………………………………………………………………………………………………

(b) What are the genotypes of the offspring? Show your working. (4mks)

(c) What is meant by co-dominance? (1mk)

……………………………………………………………………………………………………………………………………………………….

………………………………………………………………………………………………………………………………………………………

(d) State any two causes of mutations. (2mks)

……………………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………

2. (a) What is meant by the following terms?

(i) Adaptive radiation (1mk)

……………………………………………………………………………………………………………………………………………..…………

………………………………………………………………………………………………………………………………………………………..

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(ii) Vestigial structures (1mk)

…………………………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………………………

(b) Evolution is an ongoing process. State two pieces of evidence which suggest that evolution is still

taking place. (2mks)

…………………………………………………………………………………………………………………………………………….………………

……………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………………

(c) Explain how the following factors influence natural selection.

(i) Predators (2mks)

……………………………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………………………..

…………………………………………………………………………………………………………………………………………………………..

(ii) Diseases (2mks)

……………………………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………………………..

…………………………………………………………………………………………………………………………………………………………

3. An ecologist carried out a survey to estimate the number of organisms in a certain dam. The following

table shows the record of his survey.

ORGANISM NUMBER

Small fish

Mosquito larvae

Microscopic algae

Crocodiles

Large fish

4,000

9,100

450,000

95

950

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(a) (i) Construct a possible food chain of the ecosystem. (2mks)

(ii) Construct a pyramid of numbers of the ecosystem. (2mks)

(b) (i) Which of the organisms above are secondary consumers? (1mk)

…………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………….

(ii) What is the tropic level occupied by crocodiles? (1mk)

…………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………….

(c) Which organism would be depleted first in the ecosystem? Give a reason for your answer. (2mks)

……………………………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………………………….

4. A student set up materials in an experiment as shown below.

Fresh

potato

Boiled

potato

Water

Sugar

solution m

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(a) State the physiological process being investigated. (1mk)

……………………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………………….

(b) If the experiment set up was left over-night, state observation in the set up A and B. (2mks)

……………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………………………….

(c) Account for the observations in each set up. (3mks)

…………………………………………………………………………………………………………………………………………………………………..

………………………………………………………………………………………………………………………………………………………………….

………………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………………

.……………………………………………………………………………………………………………………………………………………………….

(d) If another experiment C was set such that nothing is placed in the potato cup, state and explain

the results that would have been obtained. (2mks)

…………………………………………………………………………………………………………………………………………………………………..

…………………………………………………………………………………………………………………………………………………………………..

.…………………………………………………………………………………………………………………………………………………………………

5. The figure below shows the stem of a plant growing round a tree trunk.

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(a) (i) State the response that causes the twisted growth. (1mk)

.…………………………………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………………………………

(ii) Name the hormone responsible for the growth. (1mk)

.…………………………………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………………………………

(b) Explain how the twisting process is accomplished. (2mks)

………………………………………………………………………………………………………………………………………………………………..

……………………………………………………………………………………………………………………………………………………………..

(c) (i) Name two other growth hormones in plants. (2mks)

……………………………………………………………………………………………………………………………………………………………..

…………………………………………………………………………………………………………………………………………………………….

(ii) State one way in which each of the hormones in (i) affect growth. (2mks)

………………………………………………………………………………………………………………………………………………………….

………………………………………………………………………………………………………………………………………………………..

SECTION B

Question 6 is compulsory choose one other question between 7 and 8

6. An experiment was carried out to investigate, haemolysis of human cells. The red blood cells were

placed in different concentration of sodium chloride solution. The percentage of haemolysed cells was

determined. The results were shown in the table below.

Salt conc. (g/100cm3) 0.33 0.36 0.38 0.39 0.42 0.44 0.48

Red blood cells haemolysed % 100 91 82 69 30 15 0

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(a) (i) On the grid provided plot a graph of haemolysed red blood cells against salt concentration.

(6mks)

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(ii) At what concentration of salt solution was the proportion of haemolysed cells equal to non-

haemolysed cells? (1mk)

………………………………………………………………………………………………………………………………………………………..

…………………………………………………………………………………………………………………………………………………………

(iii) State the percentage of red blood cells haemolysed at salt concentration of 0.45. (1mk)

…………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………….

(b) Account for the results obtained at:

(i)0.33% salt concentration (3mks)

………………………………………………………………….…………………………………………………………………………………………

……………………………………………………………………………………………………………………….……………………………………

………………………………………………………………………………………………………………………………….…………………………

…………………………………………………………………………………………………………………………………………….………………

(ii) 0.48% salt concentration (3mks)

…………………………………………………………………………………………………………………….………………………………………

………………………………………………………………………………………………………………………………………………………….…

……………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………….

(c) What would happen to the red blood cells if they were placed in 0.50% salt solution. (3mks)

……………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………………………..

(d) Explain what would happen to onion cells if they were placed in distilled water. (3mks)

…………………………………………………………………………………………………………………………………………………………….

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…………………………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………………………

7. Explain how various environmental factors affect the rate of transpiration in plants. (3mks)

………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………..

…………………………………………………………………………………………………………………………………………………………..

…………………………………………………………………………………………………………………………………………………………..

8. (a) State the meaning of the following terms.

(i) Digestion (2mks)

………………………………………………………………………………………………………………………………………………………….…

…………………………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………………………..

(ii) Ingestion (2mks)

…………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………..

……………………………………………………………………………………………………………………………………………………….

(b) Describe the process through which a piece of ugali undergoes in man from the time of ingestion

up to the time of absorption. (16mks)

………..…………………………………………………………………………………………………………………………………………………………………

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PROJECTION NO. 45

Name: ………………………………………………………………….…..… Candidate’s Signature ………..………..

School:………………………………………………………………………… Date: ……………………………………

231/2

BIOLOGY

PAPER 2

(THEORY)

TIME: 2 HOURS


• Write your name and index number and school in the spaces provided above.





question 8.



A 1

2

3

4

5

8

8

8

8

8

B 6

7 or

8

20

20

20

TOTAL SCORE 80

of 744




1. The diagram below represents three types of neurons found in a mammalian body.

(a) Name the neurons I, II and III. (3mks)

I…………………………………………………………………………………………………………………………………..………………..

II………………………………………………………………………………………………………………………………………………….

III…………………………………………………………………………………………………………………………………..……………

(b) Name the chemical substance responsible for the transmission of an impulse across the gap

labelled X. (1mk)

……………………………………………………………………………………………………………………………………………....….

………………………………………………………………………………………………………………………………………………….

(c) State two functions of the part labelled M. (2mks)

…………………………………………………………………………………………………………………………………………..………

…………………………………………………………………………………………………………………………………………......….

………………………………………………………………………………………………………………………………………………….

(d) In which part of the spinal cord is neurone II located? (1mk)

……………………………………………………………………………………………………....……………………………………….

………………………………………………………………………………………………………………………………………………..

(e) Using arrows indicate on the diagrams the direction followed by nerve impulse leading to a

response. (1mk)

…………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………….

I II

III

X

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2. The diagram below represents a gaseous exchange structure used in a group of living organisms.

(a) (i) Name the class of organism that uses the above gaseous exchange structure. (1mk)

…………………………………………………………………………………………………………………………..………………....….

…………………………………………………………………………………………………………………………………………………..

(ii) Apart from gaseous exchange taking place using the above structure, state two other distinguishing

characteristics of organisms that belong to the class stated in (a) (i) above. (2mks)

…………………………………………………………………………………………………………………………….……………..………

………………………………………………………………………………………………………………………….…………………....….

(b) (i) Indicate on the diagram above using letter B precise structure that experiences counter-current

phenomenon with water. (1mk)

(ii) What is the significance of counter-current flow on the structure indicated above. (2mks)

…………………………………………………………………………………………………..………………………………………………..

……………………………………………………………………………………………………....…………………………………………..

(c) (i) Name the part labelled T. (1mk)

……………………………………………………………………………………………………....………………………………………….

……………………………………………………………………………………………………………………………………………………

(ii) Give the function of the part labelled T. (1mk)

……………………………………………………………………………………………………....……………………………………………

……………………………………………………………………………………………………………………………………………………

T

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(d) Name the gaseous exchange structures in insects. (1mk)

……………………………………………………………………………………………………....………………………………………………

………………………………………………………………………………………………………………………………………………………

(e) What causes pneumonia? (1mk)

……………………………………………………………………………………………………....……………………………………………

…………………………………………………………………………………………………………………………………………………….

3. (a) State the function of each of the following apparatus.

(i) Sweep Net (1mk)

……………………………………………………………………………………………………………………………………….………....….

……………………………………………………………………………………………………………………………………………………….

(ii) Pooter (1mk)

………………………………………………………………………………………..……………………………………………………....….

………………………………………………………………………………………………………………………………………………………

(b) What is a species? (1mk)

…………………………………………………………………………………………………..………………………………………………..

……………………………………………………………………………………………………....…………………………………………..

(c) State three principles that govern Binomial nomenclature. (3mks)

…………………………………………………………………………………………………..………………………………………………

……………………………………………………………………………………………………....………………………………………….

…………………………………………………………………………………………………..……………………………………………….

……………………………………………………………………………………………………………………………………………………

(d) Why is classification of living organisms necessary. (2mks)

…………………………………………………………………………………………………..………………………………………………

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4. (a) Distinguish between homologous structures and analogous structures. Gives two examples of the

structures in each case.

(i) Homologous structures (1mk)

……………………………………………………………………………………………………………………………………………..…..………

……………………………………………………………………………………………………………………………………………….…....….

…………………………………………………………………………………………………………………………………………………………….

Example of homologous structures. (2mks)

…………………………………………………………………………………………………..…………………………………………………….

……………………………………………………………………………………………………....……………………………………………….

………………………………………………………………………………………………………………………………………………………..

………………………………………………………………………………………………………………………………………………………..

(ii) Analogous structures (1mk)

……………………………………………………………………………………………………………………………………..…………..………

……………………………………………………………………………………………………....…………………………………………………

………………………………………………………………………………………………………………………………………………………….

Examples of Analogous (2mks)

…………………………………………………………………………………………………..……………………………………………………

……………………………………………………………………………………………………....……………………………………………….

…………………………………………………………………………………………………………………………………………………………

(b) Give two examples of vestigial structures in human beings. (2mks)

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5. The diagram below represents a food web in a certain ecosystem.

(a) (i) Name the group organisms that would have the largest biomass. (1mk)

……………………………………………………………………………………………………....…………………………………………………

…………………………………………………………………………………………………………………………………………………………..

(ii) Give a reason for your answer in (a) (i) above. (1mk)

…………………………………………………………………………………………………..……………………………………………………..

……………………………………………………………………………………………………....…………………………………..……………

(b) Construct food chains ending:

(i) Tertiary consumer (1mk)

…………………………………………………………………………………………………..…………………………………………………….

……………………………………………………………………………………………………....………………………………………………..

(ii) Quaternary consumer (1mk)

…………………………………………………………………………………………………..………………………………………………………

……………………………………………………………………………………………………....……………………………………………….

Hawks

Snakes

Frogs

Slugs

Mice

Plants

Aphids Cartepillars

Bettles Insectivorous

birds

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(c) State two short term effects on the ecosystem if there was prolonged droughts. (2mks)

…………………………………………………………………………………………………..………………………………………………….

……………………………………………………………………………………………………....…………………………………………….

……………………………………………………………………………………………………………………………………………………..

………………………………………………………………………………………………………………………………………………………..

(d) (i) Suggest another group of organisms not shown in the food web but are of great importance in

the ecosystem. (1mk)

……………………………………………………………………………………………………....………………………………………………….

…………………………………………………………………………………………………………………………………………………………

(ii) What is the importance of the organisms you have named in (d) (i) above. (1mk)

…………………………………………………………………………………………………..……………………………………………………..

……………………………………………………………………………………………………....………………………………………………..

……………………………………………………………………………………………………………………………………………………………

SECTION B (40 Marks)


7. In an experiment to investigate the dry weight changes (in milligrams) of barley seedling, its

embryo and endosperm during the first 10 days after the onset of germination. The results were

as shown in the table below.

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Time (days) Dry weight of embryo Dry weight of

endosperm

Dry weight of whole

seedling

0

2

4

8

6

10

2

2

7

15

22

35

41

39

32

21

11

6

45

43

41

38

35

43

(a) Using a suitable scale and on the same axes plot graphs of dry weight of embryo, endosperm and

whole seedling against time. (8mks)

b) On which day was dry weight of endosperm same as that of embryo? (1mk)

……………………………………………………………………………………………………....……………………………………………………

……………………………………………………………………………………………………………………………………………………………

(c) What was the dry weight of the endosperm and embryo on the 5th day? (1mk)

Endosperm

……………………………………………………………………………………………………....…………………………………………………..

……………………………………………………………………………………………………………………………………………………………

Embryo

……………………………………………………………………………………………………....…………………………………………………..

…………………………………………………………………………………………………………………………………………………………….

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(d) Account for the change of dry weight of:

(i) Embryo between day 0-2 (2mks)

…………………………………………………………………………………………………..………………………………………………………..

……………………………………………………………………………………………………....……………………………………………………

(ii) Embryo between day 2-10 (3mks)

…………………………………………………………………………………………………..………………………………………………….……

……………………………………………………………………………………………………....…………………………………………………..

…………………………………………………………………………………………………..……………………………………………………….

……………………………………………………………………………………………………....……………………………………………………

(iii) Endosperm from day 0-8 (3mks)

…………………………………………………………………………………………………………………………………………………..………

……………………………………………………………………………………………………………………………………………………....….

…………………………………………………………………………………………………………………………………………..……..………

…………………………………………………………………………………………………………………………………………..………....….

(e) Name the structure that protects the radicle in hypogeal germination. (1mk)

……………………………………………………………………………………………………....………………………………………………….

……………………………………………………………………………………………………………………………………………………………

7. Describe how the skin regulates the body temperature in humans. (20mks)

8. How is the human eye adapted to its function. (20mks)

…………………………………………………………………………………………………………………………………………………..………

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……………………………………………………………………………………………………………………………………………………....….

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of 744


PROJECTION NO. 46

Name: …………………………………………………………………………………. Index no ……..…...................................

School: ……………………………………………… Candidate’s sign ……………………………….Date: …………………………………

231/2

BIOLOGY

PAPER 2

TIME: 2 HOURS







A 1 8

2 8

3 8

4 8

5 8

B 6 20

7 20

8 20

TOTAL 80

of 744


SECTION A ( 40 MARKS)


1.The diagram below represents a simple respiratory pathway in cells

a) Name the process marked X and Y. (2mks)

X…………………………………………………………………………………………………………………..………………………………..…

Y ………………………………………………………………………………………………………………………………………….……….……

b) State two differences between process X and Y. (2mks)

…………………………………………………………………………………………………………………………………….………………………

…………………………………………………………………………………………………………………………………………………………..…

……………………………………………………………………………………………………………………………………………………………..

c) State the name of substance B and condition under which it is formed. (2mks)

………………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………………..

d) Explain how body size affects the rate of respiration in animals. (2mks)

…………………………………………………………………………………………………………………………………………………………..…………

……………………………………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………………………………..

Glucose

Ethanol + CO2+ 210kJ

Substance B + 150kJ

Substance A

K, L, and M

Process X

Oxygen Process Y

Present

Plants

Animals

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2. The flow chart below represents a part of the nitrogen cycle

a) Name the groups of organism responsible for processes A and B. (2mks)

A……………………………………………………………………………………………………………………………………….…………….

B………………………………………………………………………………………………………………………………………….…..……..

b) Name the process C and D. (2mks)

C…………………………………………………………………………………………………………………………………………………….…..…

D……………………………………………………………………………………………………………………………………………………………

c) Name the chemical compound X. (1mk)

…………………………………………………………………………………………………………………………………………………………….

………………………………………………………………………………………………………………………………………………..…………

d) Give the name of a symbolic micro-organism present in leguminous plants that carriers out

process C (1mk)

………………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………………..

e) Name the chemical compound synthesized by plants using nitrogen. (1mk)

…………………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………………..

f) State the effect of process F. (1mk)

………………………………………………………………………………………………………………………………………………………………..

………………………………………………………………………………………………………………………………………………….………….

Atmospheric Nitrogen

Plants Animals

Ammonium

compounds

X

B C

D

A F

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3. The diagram below represent the structure of a nephron. Study it and answer the questions that follow.

a) (i) State the physiological process by which solutes are selectively re-absorbed back into blood at the

part labelled B. (1mk)

………………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………………

(ii) How is the part labeled B adapted to carry out the physiological process named in

3 (a) (i) above. (1mk)

…………………………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………………………..

b) In which part of the kidney is the part labelled A abundantly found. (1mk)

……………………………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………………………….

c) On the diagram above , indicate the direction of flow of blood using arrows at the part labelled C. (1mk)

…………………………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………………………….

X

B

A

C D

C

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e) State the functions carried out by the following hormones in the functioning of the nephron.

(i)Aldosterone. (1mk)

………………………………………………………………………………………………………………………………………………………………………….

………………………………………………………………………………………………………………………………………………………………………….

(ii)Anti diuretic hormone. (1mk)

………………………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………………………

4. Study the diagram below and answer the questions which follow.

a) Name the parts labelled (3mks)

A………………………………………………………………………………………………………………………………………..

B………………………………………………………………………………………………………………………………………….

D……………………………………………………………………………………………………………………………………….

b) State the functions of part B. (3mks)

………………………………………………………………………………………………………………………………………..……………………

……………………………………………………………………………………………………………………………………………...………………

…………………………………………………………………………………………………………………………………………….…………………

……………………………………………………………………………………………………………………………………………………..………

c) Removal of the ovaries after the 4th month of pregnancy does not terminate pregnancy. Explain (2mks)

……………………………………………………………………………………………………………………………………………………………..

……………………………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………………………

D

E

A

C

B

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5(a) A man marries a woman with blood group B and the couple has three children. The man disputes

parentage of the second born child, who is blood group O. His dispute is incorrect given that he belongs

to blood group A. Explain without using neither a genetic cross nor a punnet square.

(2mks)

………………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………………….

………………………………………………………………………………………………………………………………………………………………..

b) Haemophilia is a sex linked trait in humans caused by a recessive gene located in the X chromosome.

A man with normal blood cloting marries a woman who also has normal blood clotting in the event of

a cut. On getting offsprings, one of their sons turned out to be a haemophiliac. By the use of letter H for

normal blood clotting, illustrate the outcome of the haemophiliac son using a genetic cross. (4mks)

c) Other than haemophilia state two sex linked traits in human. (2mks)

………………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………………..

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SECTION B (40MARKS)

Answer questions 6(compulsory) and either questions 7 or 8 in the spaces provided

6. The data below shows the rate of photosynthesis at different temperature in attached leaves of three East

African plants. (Crotolaria, Gynandropsis and Amaranthus species) respectively which were grown outside

with the same illustration while water and carbon (IV) oxide are not limiting factors in this experiment.

Rate of photosynthesis was expressed interms of carbon (IV) oxide uptake in mg/mm2/hr at various

temperatures as tabulated below.

Temperature oC Rate of photosynthesis (mg/mm2/hr)

Gynandropsis sp Crotolaris sp Amaranthus sp

5

10

15

20

25

30

35

40

45

50

-

22

50

60

80

85

80

73

66

2

20

40

49

64

48

45

42

31

15

-

-

10

27

42

55

54

50

45

40

11

a) Represent the results graphically (rate of photosynthesis against temperature)

b) Using the graph in (a) above indicate optimum temperature for the Gynandropsis and Amaranthus

species. (2mks)

Gynandropsis …………………………………………………………………………………………………………………………..

Amaranthus ……………………………………………………………………………………………………………………………

c) Give a reason why Gynandaropsis and Amaranthus could not function photosynthetically at 5oC. (1mk)

………………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………………

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d) What are the possible ecological habitats for the following plants. (2mks)

(i) Amaranthus

……………………………………………………………………………………………………………………………………………………………….

………………………………………………………………………………………………………………………………………………………………..

(ii) Crotolaria

……………………………………………………………………………………………………………………………………………………………..

……………………………………………………………………………………………………………………………………………………………..

e) At what temperature was the amount of carbon (IV) oxide around the leaf of Gynandropsis

highest? (1mk)

………………………………………………………………………………………………………………………………………………………………..

……………………………………………………………………………………………………………………………………………………………….

f) What raw material is required in the light stage of photosynthesis. (1mk)

……………………………………………………………………………………………………………………………………………………………….

………………………………………………………………………………………………………………………………………………………………

g) Name the parts of chloroplasts in which the following stages of photosynthesis take place. (2mks)

(i) Light stage

………………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………………..

(ii) Dark stage

…………………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………………..

h) State one structural similarity and difference between chloroplast and mitochondria. (2mks)

Similarity

……………………………………………………………………………………………………………………………………………………………………..

…………………………………………………………………………………………………………………………………………………………………….

Difference

……………………………………………………………………………………………………………………………………………..………………………

…………………………………………………………………………………………………………………………………………………………………..

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i)What is the compensation point of photosynthesis? (1mk)

……………………………………………………………………………………………………………………………………………………….……………

……………………………………………………………………………………………………………………………………………………………………

7 (a) Explain why plants lack elaborate excretory organs like those found in animals. (3mks)

……………………………………………………………………………………………………………………………………………….…………………..

……………………………………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………………

(b) Name five methods of excretion in plants. (5mks)

………………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………………..

……………………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………………….

………………………………………………………………………………………………………………………………………………………………….

(c) State any six excretory products in plants and give economic uses. (12mks)

……………………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………………………

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8. Discuss the evidence of organic evolution. (20mks).

…………………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………………………….………

………………………………………………………………………………………………………………………………………………………………..……

……………………………………………………………………………………………………………………………………………………………….……

……………………………………………………………………………………………………………………………………………………………………..

…………………………………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………………………………..

……………………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………………………..

……………………………………………………………………………………………………………………………………………………………………

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…………………………………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………………………………..

…………………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………………..

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……………………………………………………………………………………………………………………………………………………………………

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PROJECTION NO. 47

NAME………………………………………… INDEX NO………………………. …………...…

SCHOOL……………………………………………...CANDIDATE’S SIGNATURE………………….

DATE……………………………………….

231/2

BIOLOGY

PAPER 2

(THEORY)

TIME: 2 HOURS

INSTRUCTIONS TO CANDIDATES • Write your name and Index number in the spaces provided.

• Answer all the questions in section A in the spaces provided on the question paper.

• In section B, answer question 6 (compulsory) and either question 7 or 8 in the



Section Question Maximum Score Candidate’s Score

A 1 - 8

2 8

3 8

4 8

5 8

B 6 20

7 20

8 20

TOTAL SCORE 80

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SECTION A

1. The diagram below represents circulatory system in animal.

(a)Name the class whose members show the circulatory system shown above. (1mk)

………………………………………………………………………………………………

………………………………………………………………………………………………

.

(b) (i) Name the parts labeled I and II (2mks)

I………………………………………………………………………………………

II……………………………………………………………………………………..

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(ii) State two difference in blood composition and flow in blood vessel R and P (2mks)

………………………………………………………………………………………………

………………………………………………………………………………………………

………………………………………………………………………………………………

………………………………………………………………………………………………

(c) (i)Explain why root pressure stops when a root is deprived of oxygen. (1mk)

………………………………………………………………………………………………

………………………………………………………………………………………………

(ii) Explain why a plant stomata may close in a hot sunny afternoon only to re open a

short while later. (2mks)

……………………………………………………………………………………………….

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2. A farmer mated his dark red cow to a while bull. The cow gave birth to a light red calf.

(a) State why the calf is light red and not dark red or white. (1mk)

……………………………………………………………………………………………….

………………………………………………………………………………………………

(b) If a light red bull is mated to a dark red cow, work out using a genetic cross:

(i) The genotypes of the offspring. (4mks)

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(ii) The genotypic ratio of the offspring. (1mk)

……………………………………………………………………………………………….

……………………………………………………………………………………………….

(iii) The phenotypic ratio of the offspring. (1mk)

……………………………………………………………………………………………….

……………………………………………………………………………………………….

(iv) The probability of getting a light red offspring from the cross. (1mk)

……………………………………………………………………………………………….

……………………………………………………………………………………………….

3. A group of students set up an experiment to investigate a certain physiological process.

The set up was as shown below:

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After sometimes, the students observed that a sugar solution was formed and its level rose



………………………………………………………………………………………………

……………………………………………………………………………………………….

(b) Account for the formation of sugar solution and its rise in level. (3mks)

………………………………………………………………………………………………

………………………………………………………………………………………………

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……………………………………………………………………………………………….

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(c) Suggest the result that the students would obtain if they repeated the experiment

using a boiled pawpaw. Give reasons. (2mks)

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……………………………………………………………………………………………….

……………………………………………………………………………………………….

………………………………………………………………………………………………

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(d) State two importance of the physiological process named in 3(a) above to plants.

(2mks)

……………………………………………………………………………………………….

……………………………………………………………………………………………….

……………………………………………………………………………………………….

4. (a) Explain the term Eutrophication. (3mks)

………………………………………………………………………………………………

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(b) How does eutrophication lead to death of fish in a water body? (3mks)

………………………………………………………………………………………………

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………………………………………………………………………………………………

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.

(c) Persistent use of agricultural inorganic fertilizers lead to loss of soil fertility.

Account for this observation. (2mks)

………………………………………………………………………………………………

………………………………………………………………………………………………

………………………………………………………………………………………………

……………………………………………………………………………………………….

5. An ecological study of woodland was carried out and the following observations recorded.

• Rabbits feed on plants

• Hawks feed on rabbits and small birds

• Snails feed on plants

• Fox feed on rabbits and small birds.

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(a) Using the above observations, construct a food web. (3mks)

(b) From your food web;

(i) Draw a food chain that ends with hawks as tertiary consumers. (1mk)

(ii) Name two carnivores that compete in the woodland and state the food they

compete for. (1mk)

………………………………………………………………………………………………

.

(c) Suggest the most likely method of sampling used to estimate the rabbit population

in the woodland . (1mk)

………………………………………………………………………………………………

……………………………………………………………………………………………….

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(d) State two precautions to be taken when using the sampling method named in (c)

above. (2mks)

………………………………………………………………………………………………

………………………………………………………………………………………………

……………………………………………………………………………………………….

SECTION B: Answer question 6 (compulsory) and either question 7 or 8.

6. An experiment was carried out to investigate the effects of hormones on growth of lateral

buds of three pea plants.

The shoots were treated as follows;

Shoot A – Apical bud was removed

Shoot B – Apical bud was removed and gibberellic acid placed on the cut shoot.

Shoot C - Apical bud was left intact.

The length of branches developed from lateral buds was determined at reular intervals.

The results obtained are as shown in the table below:

Time in days Shoot A Shoot B Shoot C

0

2

4

6

8

10

3

10

28

50

80

118

3

12

48

90

120

152

3

3

8

14

20

26

Length of Shoot in millimeters

millimetrtes

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(a)Using the same axes, draw graphs to show length of branches against time. (8mks)

(b)

(i) What was the length of the branch in Shoot B on the 7th day? (1mk)

…………………………………………………………………………………………….

……………………………………………………………………………………………….

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(ii) What would be the expected length of the branch developing from Shoot A

on the 11th day? (1mk)

………………………………………………………………………………………………

……………………………………………………………………………………………….

(c) Account for the result obtained in the experiment. (6mks)

……………………………………………………………………………………………….

……………………………………………………………………………………………….

………………………………………………………………………………………………

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………………………………………………………………………………………………

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.

(d) Why was Shoot C included in the experiment? (1mk)

……………………………………………………………………………………………….

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……………………………………………………………………………………………….

(e) What is the importance of gibberellic acid in Agriculture? (1mk)

………………………………………………………………………………………………

……………………………………………………………………………………………….

(f) State two physiological processes that are brought about by the application of

gibberellic acid on plants.

(2mks)

………………………………………………………………………………………………

………………………………………………………………………………………………

………………………………………………………………………………………………

………………………………………………………………………………………………

7. Describe the adaptations of a dicotyledonous stem to its functions. (20mks)

8. Describe the economic importance of members in the kingdom fungi giving appropriate

examples where possible. (20mks)

………………………………………………………………………………………………………

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PROJECTION NO. 48

NAME ___________________________________________ INDEX NO. ______________________

CANDIDATE’S SIGNATURE _________

DATE __________________________

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231/2

BIOLOGY

PAPER 2

(THEORY)

2 HOURS


- This paper consists of two sections A and B. Attempt all the questions in section A. In section B, attempt question 6 and

either question 7 or 8 in the spaces provided after question 8.

Section Questions Max. score Candidates score

A 1

2

3

4

5

8

8

8

8

8

B 6 20

7 20

8 20

Total marks 80

Turn Over


Attempt all the questions in this section

1. The diagram below shows the exchange of gases in the alveolus. Study it and answer the questions

that follow.

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(a) Name the gases named A and B

A ______________________________________________________________ (1mk)

B ______________________________________________________________ (1mk)

(b) State the importance of the gas marked B in tissues (1mk)

__________________________________________________________________________________________

__________________________________________________________________________________________

(c) Name parts marked K and P (2mks)

K ________________________________________________________________________________________

P _______________________________________________________________________________________

(d) State the adaptations of the alveolus to its function (3mks)

____________________________________________________________________________________________

___________________________________________________________________________________________

____________________________________________________________________________________________

___________________________________________________________________________________________

2. In human beings, a downward pointed frontal hairline (“windows peak”) is a heritable trait. A

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person with windows peak always has at least one parent who has this trait; where as persons with frontal hairline

may occur in families in which one or even both parents have windows peak. Using W and w to symbolize genes for this trait.

(a) Determine the F1 generation if a homozygous windows peak male parent is married to a

homozygous frontal hairlined female parent (4mks)

(b) State two causes of variations (1mk)

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

© Name two sex linked genetic disorders affecting human females and males (2mks)

______________________________________________________________________________

______________________________________________________________________________

_______________________________________________________________________________

(d) What is genome (1mk)

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

3. (a) State the two principle functions of the kidney (2mks)

(i)

______________________________________________________________________________

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______________________________________________________________________________

______________________________________________________________________________

(ii)

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

3.

(b) The figure below shows a highly magnified cross-section of a proximal convoluted tubule

of a mammalian kidney. Study it and answer the questions that follow

Wall of capillary Q Wall of tubule

(i) From the diagram, identify three structural features that adapt the proximal convoluted tubule to

its function (3mks)

______________________________________________________________________________

______________________________________________________________________________

_______________________________________________________________________________

______________________________________________________________________________

(ii) Name the physiological process involved in the reabsorption of water and glucose from the

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proximal convoluted tubule to the blood stream

Water (1mk)

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

Glucose (1mk)

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

(c) Which fluid substance flows in the part labelled Q (1mk)

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

4. What is meant by the following?

(a) (i) Continental drift (1mk)

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

4.

(ii) Vestigial structure (1mk)

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

(iii) Convergent evolution (1mk)

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

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(b) Penicillin is an antibiotic which attacks active bacteria. Recent studies have shown

that most bacteria have become resistant to it. Briefly explain why this is so (5mks)

______________________________________________________________________________

______________________________________________________________________________

_______________________________________________________________________________

______________________________________________________________________________

________________________________________________________________________________

_______________________________________________________________________________________

_______________________________________________________________________________________

5. The diagram below represents a cell organelle

(a) Name the organelle (1mk)

______________________________________________________________________________

______________________________________________________________________________

(b) Name parts marked X, Y and Z (3mks)

X _______________________________________________________________________

Y _______________________________________________________________________

Z _______________________________________________________________________

(c) Write a word equation of the chemical reactions that occur at

X

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______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

Y

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

(d) State two factors influencing the reactions at X and Y above (2mks)

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________


Answer question 6 (compulsory) in the spaces provided and either question 7 or 8 in


6. Form three students in Mua secondary school studied the population growth of two species of flour

beetles. T confusum and T. casteanum. The beetles were grown in a box with limited supply of maize flour. The box was kept

in a warm place for 200 days. The beetles were counted at certain intervals and the results tabulated as shown below.

(a) Using the same axis draw the graphs of the number of beetles in the box against time (8mks)

No of Days 0 10 50 60 80 100 120 140 180 200

No. of Beetles T. confusum 20 20 30 80 130 150 162 160 160 160

T. Casteanum 20 20 30 43 50 40 15 10 6 2

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(b) How many beetles were present on the 70th day?

T. Confusum

_______________________________________________________________________________

_______________________________________________________________________________

T. Casteanum (2mks)

_______________________________________________________________________________

_______________________________________________________________________________

(c) Account for the shape of T. confusum curve between day

(i) 0 -10 (2mks)

_______________________________________________________________________________

_______________________________________________________________________________

_______________________________________________________________________________

(ii) 60-80 (2mks)

_______________________________________________________________________________

_______________________________________________________________________________

_______________________________________________________________________________

(iii) 120-140 (2mks)

_______________________________________________________________________________

_______________________________________________________________________________

_______________________________________________________________________________

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(d) (i) Suggest what happened to T. Casteanum between day 80 and 160 (2mks)

_______________________________________________________________________________

_______________________________________________________________________________

_______________________________________________________________________________

_______________________________________________________________________________

_______________________________________________________________________________

(ii) What biological phenomenon is represented by observation made in d(i) above (1mk)

_______________________________________________________________________________

_______________________________________________________________________________

_______________________________________________________________________________

(e) State one factor that may determine the distribution of animals in a given area (1mk)

_______________________________________________________________________________

_______________________________________________________________________________

_______________________________________________________________________________

7. Describe the structure and functions of various parts of the human skin (20mks)

8. Describe the role of growth hormones in plant growth and development (20mks)

_______________________________________________________________________________

_______________________________________________________________________________

_______________________________________________________________________________

_______________________________________________________________________________

_______________________________________________________________________________

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PROJECTION NO. 49

Name..................................................................................... Index No .............................................

School.................................................................................... Candidates Signature………….………

Date: ……………………...…………….

231/2

BIOLOGY PAPER

Paper 2(Theory)

Time: 2 Hours


• Answer all questions in section A by filling in the spaces provided.

• In Section B, Answer Question 6 (Compulsory Question) and any other One Question from the

remaining two Questions.

(i.e. 7 or 8)



A 1 8

2 8

3 8

4 8

5 8

B

6 20

7 20

8 20

80

This paper consists of 8 printed pages.


Total Score

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Answer ALL questions in this section in the space provided below.

1. (a) What is meant by the term sex linkage? (1 Mark)

…………………………………………………………………………………………………………..………………………………………………

………………………………………………………………………………………………..…………………………………………………………..

(b) Name two sex-linked traits in humans. (2 Marks)

…………………………………………………………………………………………………………..………………………………………………

…………………………………………………………………………………………….…………………………………………………………..

(c) In Drosphilamelanogaster, the inheritance of eye color is sex-linked. The gene for the red eye is

dominant. A cross was made between a homozygous red-eyed female and a white eyed male.

Work out the phenotypic ratio of F1 generation. (5 Marks)

(Use R to represent the gene for red eyes).

2. A response exhibited by a certain plant tendril is illustrated below.

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Blood Cells

Water

a) (i) Name the type of response. (1 Mark)

…………………………………………………………………………………………………………..………………………………………………

…………………………………………………………………………………………………………………………………………………………..

(ii) Explain how the response named in a (i) above occurs. (3 Marks)

…………………………………………………………………………………………………………..………………………………………………

………………………………………………………………………………………………………………………………………………………….

b) What is the importance of tactic response to microscopic plants? (1 Mark)

…………………………………………………………………………………………………………..………………………………………………

……………………………………………………………………………………………..…………………………………………………………..

c) State three applications of plant hormones in Agriculture. (3 Marks)

…………………………………………………………………………………………………………..………………………………………………

…………………………………………………………..………………………………………………………………………………………………

…………..…………….………………………………………………………………………………………………………………………………..

3. The diagram below shows how gaseous exchange occurs across the gills in fish.

(a) According to the diagram water and blood flow in opposite direction across the gills.

(i) Give the term used to describe this flow. (1 Mark)

…………………………………………………………………………………………………………..………………………………………………

…………………………………………………………………………………………………………………………………………………………..

gills

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(ii) Explain the advantage of the above flow named in a(i) above. (2 Marks)

…………………………………………………………………………………………………………..………………………………………………

…………………………………………………………………………………………………………………………………………………………..

…………………………………………………………………………………………………………………………………………………………..

(b) What difference would be observed if water and blood flows across the gills in the same

direction? (2 Marks)

…………………………………………………………………………………………………………..………………………………………………

……………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………………

(c) In which structures in the gills does gaseous exchange take place? (1 Mark)

…………………………………………………………………………………………………………..………………………………………………

……………………………………………………………………………………………………………………………………………………………

(d) Name two organs in man which display the flow system named in a(i). (2 Marks)

…………………………………………………………………………………………………………..………………………………………………

……………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………………

4. An experiment was carried out to investigate the effect of different concentrations of Sodium

Chloride on human red blood cells. Equal volumes of blood were added to equal volumes of

salt solutions of different concentrations. The results were as shown below:-

Set up Sodium Chloride

concentration

Shape of red blood cells

at the end of experiment

Number of red blood

cells at the end of

experiment

A

B

0.9%

0.3%

Normal

Swollen

No change in number

Fewer in number

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a) If the experiment was repeated with 1.4% Sodium Chloride solution, state the results you

would expect with reference to:-

(i) Number of red blood cells. (1 Mark)

…………………………………………………………………………………………………………..………………………………………………

……………………………………………………………………………………………………………………………………………………………

(ii) Appearance of red blood cells when viewed under the microscope. (1 Mark)

…………………………………………………………………………………………………………..………………………………………………

…………………………………………………………………………………………………………………………………………………………..

b) Account for the fewer number of red blood cells in 0.3% Sodium Chloride salt solution.(3 Marks)

…………………………………………………………………………………………………………..………………………………………………

……………………………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………………………….

c) Give the biological term which can be used to describe 0.9% Sodium chloride solution.

(1 Mark)

…………………………………………………………………………………………………………..………………………………………………

…………………………………………………………………………………………………………………………………………………………..

d) Define plasmolysis. (1 Mark)

…………………………………………………………………………………………………………..………………………………………………

……………………………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………………………..

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5. To estimate the population size of crabs in a certain lagoon, traps were laid at random. 400 crabs

were caught marked and release back into the lagoon. Four days later traps were laid again and 374

crabs were caught out of the 374 crabs, 80 were found to have been marked.

a) Calculate the population size of the crabs in the lagoon using the formula below. (2 Marks)

N = 𝑛 𝑥 𝑀

𝑚

Where N = total population of crabs in the lagoon

n = total number of crabs in the first catch

M = number of crabs in the second catch

m = number of marked crabs in the second catch

b) State two assumptions that were made during the investigations. (2 Marks)

…………………………………………………………………………………………………………..…………………………………………………

………………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………….

c) What is the name given to this method of estimating the population size? (1 Mark)

…………………………………………………………………………………………………………..…………………………………………………

…………………………………………………………………………………………………………………………………………………………

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d) State one precaution to be taken when carrying out this method of estimating population size.

(1 Mark)

…………………………………………………………………………………………………………..………………………………………………

……………………………………………………………………………………………………………………………………………………………

e) Give two other methods used in estimating population size. (2 Marks)

…………………………………………………………………………………………………………..………………………………………………

…………………………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………………………

SECTION B (40MARKS)


6. A hungry person had a meal, after the concentration of glucose and amino

acids in the blood were determined. This was measured hourly as the blood

passed through the hepatic portal vein and the iliac vein in the leg. The results

were as shown in the table below.

Time (hrs) Concentration of contents in the hepatic portal vein (mg / 100ml)

Concentration of contents in the iliac vein (mg / 100ml)

Glucose Amino acids Glucose Amino acids

0

1

2

3

4

5

6

7

85

85

140

130

110

90

90

90

1.0

1.0

1.0

1.5

1.5

3.0

2.0

1.0

85

85

125

110

90\

90

90

90

1.0

1.0

1.0

1.5

3.0

2.0

1.0

1.0

a) Using the same axis, draw graphs of concentration of glucose in the

hepatic portal vein and the iliac vein of the leg against time. (7 Marks)

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b) Account for the concentration of glucose in the hepatic portal vein from;

i) 0 - 1hr (2Marks)

…………………………………………………………………………………………………………..…………………………………………………

…………………………………………………….………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………………

ii) 1 - 2hrs (3Marks)

…………………………………………………………………………………………………………..…………………………………………………

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iii) 2 - 4hrs (2

Marks)

…………………………………………………………………………………………………………..…………………………………………………

…………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………….

iv) 5 - 7 hrs (2

Marks)

…………………………………………………………………………………………………………..…………………………………………………

…………………………………………………….………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………………………..

c) Account for the difference in concentration of glucose in hepatic portal vein and the iliac vein

between 2 and 4 hrs. (3

Marks)

…………………………………………………………………………………………………………..…………………………………………………

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d) Using the data provided in the table, explain why the concentration of amino acids in the

hepatic portal vein took longer to increase. (1 Mark)

…………………………………………………………………………………………………………..…………………………………………………

……………………………………………………………………………………………………………………………………………………………..

7. a) Explain the roles of the mammalian placenta. (7 Marks)

c) Describe how hormones regulate the menstrual cycle in human females. (13 Marks)

8. Describe causes and methods of controlling water pollution. (20 Marks)

…………………………………………………………………………………………………………..…………………………………………………………

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………………………………………………………………………………………………………………………………………………………………………

PROJECTION NO. 50

NAME:…………………………………………………………………………………………………… INDEX NO:…………………………

SCHOOL:……………………………………………………………………………………………….... DATE:………………………………. .

SIGN:………………………………..

231/2

BIOLOGY

PAPER 2

(THEORY)

TIME: 2 HOURS









A 1

2

3

4

5

8

8

8

8

8

B 6

7

20

20

of 744


8 20

TOTAL 80


SECTION A( 40 MARKS)


2. The diagram below illustrates and experiment to determine the rate of respiration in a small

insect.

a) Name the chemical compound labelled X and state its function. (2mks)

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b) Why is it necessary to place the flask in a water bath. (3mks)

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c) What changes would you expect to observe in the level of coloured water in the

capillary tube after the experiment has run for five minutes. (1mk)

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d) Explain the changes you have started in ( c) above. (3mks)

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e) State how you can set up a control experiment . (1mk)

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2. The diagram below represents a plant cell organelle

a) Name the organelle. (1mk)

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b) In which of the labelled parts does carbon (IV) Oxide fixation occur? (1mk)

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c) Name the parts labelled A and B and state how each is adapted to its functions. (4mks)

A

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B

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d) Explain what would have happened to the structures labelled X had the plant been kept in

darkness for 48 hours. (2mks)

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a) Name the structures labelled W,X, and Y. (3mks)

. X ..................................................................................................................

Y .................................................................................................................

Z ....................................................................................................................

b) State two functions of the pollen tube. (2mks)

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c) What happens to antipodal cells after fertilization. (1mk)

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d) Name the structure labelled K and state their role. (2mks)

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4. a) Name any three defects of the circulatory system in humans. (3mks)

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b) How are leucocytes adapted to their function. (2mks)

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c) Name the blood vessel with the highest ionic extraction of

i) Glucose (1mk)

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ii) Carbon (IV) Oxide. (1mk)

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d) What is the importance of tissue fluid. (1mk)

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5. Below is a pedigree chart showing the incidences of colour blindness trait linked to the X –

chromosome transmitted through a recessive gene. Study the diagram and answer the following

questions.

a) Gives the genotypes of person 1 and 2

1 ............................................................................

2 ...............................................................................

b) Explain why there are no male carriers for this conduction. (1mk)

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6. Explain why there are more color blind male than female in a population. (3mks)

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SECTION B( 40 MARKS)

Answer questions 6 ( compulsory)and either questions 7 or 8 in the spaces provided questions 8

7. The glucose level in mg per 100cm3 of blood was determined in two person Y and Z. Both had stayed

for six hours without taking food. They were fed on equal amount of glucose at the start of the

experiment .The amount of glucose in their blood was determined at intervals .The results are shown

in the table below.

Times in minutes Glucose level in blood in mg

/100cm3

Y Z

0 85 78

20 105 110

30 105 110

45 130 170

60 100 195

80 93 190

100 90 140

120 90 130

140 88 120

a) On the grid provided, plot graphs of glucose levels in blood against time on the same axes.

(7mks)

b) What was the concentration of glucose in the blood of Y and Z at the 50th minute?

(2mks)

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Y ..........................................................................................................................

Z .........................................................................................................……………….

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c) Account for the level of glucose in present Y

i) During the first 45 minutes. (2mks)

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ii) After 45th minute to the end. (4mks)

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d) Account for the decrease in glucose level person Z after 60 minutes. (2mks)

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e) Low blood sugar level in harmful to the body .Explain. (3mks)

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7. a) What assumption are made when using the captured recapture method in estimating

population of animals. (5mks)

b) Describe how you would use the capture – recapture method to estimate the population of

fish in the school pond. (15mks)

8. Describe the structure and function of the various parts of the mammalian brain. (20mks)

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PROJECTION NO. 51

NAME:………………………………………………………………………………………….………………INDEX …………………………..…..…..

SCHOOL:…………………………………………………………..………………SIGNATURE……………………………… DATE…………….…

231/2

BIOLOGY

PAPER 2

(Theory)

TIME: 2HOURS

Kenya Certificate of Secondary Education 231/2

BIOLOGY

PAPER 2


6. Write your name and index number in the spaces provided.

7. Sign and write the date.

8. This paper consists of two sections. A and B.


10. In section B, answer question 6 (compulsory) and either question 7 or 8 in the spaces provided.



A 1 9

2 8

3 7

4 8

5 8

B 6 20

7 20

8 20

TOTAL SCORE 80

of 744


SECTION A

Answer all questions in the spaces provided

1. The diagram below shows some components of a light microscope.

e) Name the parts labeled (2mrks)

K ………………………………………………………………………….……………………………………………………

M …………………………………………………………………………………….……………………………………….

f) State the functions of (2mrks)

P ……………………………………………………………………………………………………………………………………..

Q ……………………………………………………………………………………………………………………………………..

g) A student was viewing a prepared slide of a plant cell under high power microscope. The

features of the cell were blurred. Which one of the labelled parts of the microscope

would the student use to obtain:-

(i) a sharper outline of the features. (1mrk)

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(ii) Give the formula used to calculate magnification in a light microscope. (1mrk)

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h) A student was preparing a section of a plant cell to be viewed on a light microscope. Give

a reason for each of the following steps:-

(i)Cutting a very thin section (1mrk)

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(ii)Staining the section (1mrk)

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(iii)Putting the section in water (1mrk)

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2. a) Explain what happens to excess amino acids in the liver of humans. (4mrks)

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b).i) What would happen if a person produced less anti-diurectic hormone? (1mrk)

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ii) What term is given to the condition described in (b) (i) above? (1mrk)

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c) State two portions of the human nephrone found only in the cortex of the kidney. (2mrk)

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3. The diagram below shows a set up that was used to demonstrate fermentation.

Glucose solution was boiled and oil added on top of it. The glucose solution was then allowed to

cool before adding yeast suspension.

e) Why was the glucose solution boiled before adding the yeast suspension? (1mrk)

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f) What was the importance of cooling the glucose solution before adding the yeast

suspension? (1mrk)

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g) What was the use of the oil in the experiment? (1mrk)

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h) Give two reasons why accumulation of lactic acid during vigorous exercise lead to an

increase in heart beat. (2mrks)

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Oil layer

Delivery tube

A B

Limewater Glucose solution and yeast suspension

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e).Other than carbon (iv) oxide, name the other products of anaerobic respiration in plants.

(2mrks)

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4. In an experiment, a black mouse was mated with a brown mouse; all the off-springs were

black. The off-springs grew and were allowed to mate with one another. The total number

of (F2) generation off-springs was 96.

b) Using the letter symbols capital letter B for the gene of black colour and small b for brown

colour, Work out the genotype of the F1 generation. (3mrks)

b) From the information above, work out the following for the F2 generation.

i) Genotypic ratio. (2mrks)

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ii) Phenotypic ratio. (1mrk)

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iiii) The total number of brown mice (2mrks)

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5. When a person’s hand accidentally touches a hot object it is quickly withdrawn, below is the

diagram showing how response occurs

a).Describe a reflex action that will lead to the withdrawal of hand from an object. (7mrks)

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b).Name the substance responsible for the transmission of an impulse across the

synapse. (1mrk)

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B A

C

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SECTION B

Answer question six and any other one question from this section in the spaces

provided.

6. (Compulsory)

An investigation was carried out between 1964 and 1973 to study the changes in fish

population in a certain lake. Four species of fish A, B, C and D were found to live in the lake. In

1965, a factory was built near the lake and was found to discharge hot water in the lake raising the

temperature from 25o c to 30o c. In 1967, sewage and industrial waste from a nearby town was

diverted into the lake. In 1969, discharge of hot water, sewage and industrial waste into the lake

was stopped. The fish populations during the period of investigation are shown in the table below.

Fish population during the period of investigation

Fish species 1964 1966 1968 1970 1971 1971 1973

A 6102 223 20 106 660 4071 7512

B 208 30 11 22 63 311 405

C 36 100 0 0 0 0 0

D 4521 272 23 27 79 400 617

c) (i) In which year was the fish population lowest? (1mrk)

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(ii)State the factors that might have caused the lowest fish populations during the year

you have stated in (a) (i) above. (3mrks)

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(iii)Explain how each factor you have stated in (a) (ii) above could have brought about the

changes in the fish populations. (11mrks)

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(iii) Why did fish species C remain 0 after 1969? (1mrk)

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b).Other than the factors stated in (a) (i) above, state other four that may affect the

population of fish in the lake. (4mrks)

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7 (a). What is meant by the term digestion? (2mrk)

(b) Describe how the mammalian small intestine is adapted to its function. (18mrks)

8. Discuss the various evidences which show that evolution has taken place. (20mrks)

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PROJECTION NO. 52

Name…………………………………………………………………………… Index No………………………………………………………..

School………………………………………………………………………….. Date………………………………………..………..……………

Candidate’s signature…………………………………..

231/2

BIOLOGY

Paper2

Time 2Hours













A 1

2

3

4

5

08

08

08

08

08

B 6

7

8

20

20

20

TOTAL SCORE 80

of 744


1. In a garden with plants of the same species, 705 plants had red flowers while 224 had white flowers.

a) Work out the ratio of red to white flowered plants (1mark)

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b) i) Using letter R to represent the dominant gene , work out a cross between F1

offspring and a white flowered plant. ( 4 marks)

ii) What is the genotypic ratio from the cross in b)(i) above?

Genotypic ratio (1 mark)

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Phynotypic ratio (1 mark)

………………………………………………………………………………………………………………………………………………………………

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c) What is meant by the term allele? (1 mark)

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2. In a physiological experiment, starch, protein, diastase and sodium chloride were added to water

and put inside a visking tubing. The visking tubing was then placed in a water bath maintained at a

temperature between 35 - 40°C. The set up was as shown in the diagram below.

The following observations were made after the procedures indicated.

Contents in At the start of experiment After 1 hour

Visking tubing i) Solution tastes salty Solution tastes salty

ii) Visking tubing is not firm Visking tubing is firm

iii) After boiling with Benedicts

solution, solution remains blue

After boiling with Benedicts solution the

solution turns brown

iv) On addition of solution

hydroxide followed by copper

sulphate solution to the solution,

the colour changes to purple

On addition of sodium hydroxide

followed by coppers sulphate to the

solution, the colour changes to purple

Beaker i) Water is tasteless Solution tastes sweet/salty

ii) After boiling solution with

Benedicts solution, Blue colour

remains

After boiling solution with Benedicts

solution, colour turns to brown

iii) On addition to sodium hydroxide


colour remains blue

On addition of sodium hydroxide


colour remains blue

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a) Name the process by which salt moved into the water in the beaker from the visking tubing.

(l mark)

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b) i) Name the food substance responsible for the brown colour observed after 1 hour

both in the beaker and visking tubing when solutions are boiled with benedicts solution. (l mark)

………………………………………………………………………………………………………………………………………………………………

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ii) Account for the observation in (b i) above. (3 marks)

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c) i) Name the food substance tested with sodium hydroxide followed by copper

sulphate solution(s) (1 mark)

………………………………………………………………………………………………………………………………………………………………

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.………………………………………………………………………………………………………………………………………………………………

ii) Account for the absence of the food substance named in (c i) above in the beaker

after 1 hour. (l mark)

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d) After one hour the visking tubing was firm. State the term used to describe this state. (1 mark)

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3. a) Distinguish between natural and acquired immunity (l mark)

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b) Define the term allergy (l mark)

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c) The chart below shows the blood clotting mechanism

i) Name the blood cells represented by X (1mark)

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ii) The end product of the mechanism represented by Z (1 mark)

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d) Explain how the following environmental factors increase the rate of transpiration.

i) Temperature (2 marks)

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ii) Humidity (1 mark)

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iii) Atmospheric pressure (1 mark)

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a) Name the structures labeled H and J (2 marks)

H

………………………………………………………………………………..

J

……………………………………………………………………………….

b) State how the structures labeled H, M and N are adapted to their functions.(3 marks)

H

………………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………..………………………………………………

M

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N

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c) State what would happen if the structure labeled K was completely damaged. (1 mark)

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d) Name the fluid contained in structure N. (1 mark)

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e) Apart from hearing, state the other role performed by the human ear. (1 mark)

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5. The structures below represent specialized cells in man.

a) Identify structure X, Y and Z.

X ………………………………………………………………… ( l mark)

Y ………………………………………………………………… (1 mark)

Z………………………………………………………………… (1 mark)

b) Give a reason for your answer for X in (a) above. (1 mark)

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c) Give two adaptation of Z to its function. (2 marks)

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d) What is tissue fluid? (2 marks)

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SECTION B(40 MARKS)

Answer question 6(Compulsory) in the spaces provided and either question 7 or 8 in


6. The table below shows the population of a housefly musca domestica which is parasitized by wasps

of species Nasonia spp. The investigation of their population growth pattern was carried out for 70

weeks. In these experimental space and physical factors were assumed to be limiting.

a) Using the readings in the table, plot graphs on the same axis of population growth

of organisms against time. (8 marks)

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b) Account for the growth of

i) Musca domestica between 10th week — 25th week. (1 mark)

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ii) Nasonia species between 40th week –50th week. (1 mark)

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c) What is the population of?

i) Nasonia spp. on the 62nd week? (1 mark)

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ii) Musca doniestica on the 4th week? (1 mark)

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d) Bemex, another parasite of housefly was introduced into the ecosystem. Giving a

reason; what will be the effect on the population of

i) Housefly Musca domestica. (2 marks)

………………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………….

ii) Nasonia Spp. (2 marks)

………………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………….

e) In estimating the population of Musca domestica in the experiment above.

Capture-mark release recapture method was used. Describe the procedure which

was followed.

(4 marks)

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7. a) What is natural selection? (2 marks)

b) Describe how natural selection brings about adaptations of a species of a living

organism to its environment (18 marks)

8. a) Describe how urea is formed (5 marks)

b) Describe the path followed until it is eliminated from the body (15 marks)

………………………………………………………………………………………………………………………………………………………………

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PROJECTION NO. 53

NAME:……………………………………………………… INDEX NO:…………………………

SCHOOL:………………………………………………….. DATE:……………………………….

SIGN:………………………………..

231/2

BIOLOGY

PAPER 2

(THEORY)

TIME: 2 HOURS


1. Answer ALL questions in section A in the spaces provided.

2. In section B answer question 6 (compulsory) and either question 7 or 8 on the foolscap provided.

3. Candidates will be penalized for not following instructions in this paper carefully.

4 All workings must be clearly shown where necessary.



A 1

2

3

4

5

08

08

08

08

08

B 6

7

8

TOTAL 80

of 744



1. The figure below illustrate a response in plants.

(a) State the type of response illustrated (1mk)

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(b) Explain how the response occurs. (4mks)

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(c) State two importance of phototactic response in termites. (2mks)

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(d) State hormone used in agriculture that breaks breaking seed dormancy. (1mk)

…………………………………………………………………………………………………………………………………………………………….

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2. (a) (i) Define sex linkage. (1mk)

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(ii) In a marriage of Jane and Otieno who are both normal for hemophiliac condition,

gave birth to children Susan, Grace, Tom and Peter. Tom the second born

child was hemophilic. Later in life Tom married Alice who was normal. Their first

born child was hemophiliac.

Let H represent gene for normal condition.

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(b) (i) What was the genotype of Alice. (1mk)

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(ii) Work out the phenotypic ratio of F2. (5mks)

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(c) How does the police force use knowledge on genetics. (1mk)

…………………………………………………………………………………………………………………………………………………………….

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(d) What is the name given to points of contact in a pair of homologous

chromosomes. (1mk)

………………………………………………………………………………………………………………………………………………………….…..

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3. A student observed feeding relationship while on a tour in a coastal Island.

Eagles feed on small fish.

Small fish feed on sea grass

Insect larvae and molluscs feed on sea grass.

Insect larvae fed on by small fish, while crabs feed on insect larvae and molluscs.

(a) From the above information , construct a food web. (3mks)

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(b) In which trophic level is small fish found. (1mk)

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(c) Extract a food chain where the Eagle is a tertiary consumer. (1mk)

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(d) Suppose all the crabs were poisoned, what would be the immediate effect in the

ecosystem. Give a reason. (1mk)

………………………………………………………………………………………………………………………………………………………..

………………………………………………………………………………………………………………………………………………………..

(e) Give a reason why pyramid of biomass is a better representation of energy flow in an

eco system than pyramid of numbers. (1mk)

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4. A student wanted to observe human red blood cells under a light microscope. He put l0ml of

solution X,Y and Z in three boiling test tubes. The solutions were of different concentration .In

each of the test tubes he put three drops of blood sample. The experiment was left to stand for 30

minutes. He placed one drop of solution X on glass slide and observed under the microscope.

The same procedure was repeated for solutions Y and Z.

He made the following observation.

Solution Observation

X Normal Cells

Y Wrinkled Cells

Z No cells observed

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(a) What was the physiological process observed. (1mk)

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(b) Explain why red blood cells observed in solution Y were wrinkled. (3mks)

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(c) A 3cm long piece of kale (sukuma wiki) stem was cut halfway along its length as

shown below.

(i) If the piece was placed in solution Z for 30 minutes, its shape changed . Using a pencil

draw a diagram in the space provided to show the expected change. (1mk)

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(ii) Explain the results obtained in C(i) above. (3mks)

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5. An experiment was set up as shown below.

(a) A student blew air in and out through point X. Using arrows indicate on the diagram how

air gets in and out of the set up. (2mks)

(b) (i) In which of the test tube would lime water turn milky first. (1mk)

……………………………………………………………………………………………………………………………………………………….

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(ii) Give a reason. (1mk)

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(c) What is the effect of lactic acid in the thigh muscles of an athlete after a short fast race.

(2mks)

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(d) Identify the type of muscle in human being where formation and effect of lactic acid is

not felt. (1mk)

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(e) What is the biological significance of boiling milk /ultra heat treated milk. (1mk)

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SECTION B

COMPULSORY QUESTIONS.

6. A man was starved for 24hours.He was then served with a balanced diet after which the

concentration of glucose in the hepatic and hepatic portal veins were determined at interval of 1

hour for the next 8 hours after the meal.

The results were as shown in the graph below.

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(a) From the graph state the normal concentration of glucose in man. (1mk)

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(b) Determine the concentration of glucose after 2 ½ hrs. (2mks)

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(c) Calculate the rate of glucose between 1 - 2 hours in hepatic portal vein. (2mks)

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(d) Account for the blood sugar level in hepatic portal vein and hepatic vein between;

(4mks)

(i) 0- 1hour

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(ii) 2 - 4 hours. (6mks)

(e) A patient was found to produce urine that tasted sweet. Name the disease he was likely

to be suffering from. (1mk)

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(f) How would you test for the disease in your school laboratory. (3mks)

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(g) What advice would you give to a patient whose blood contains abnormal high

levels of urea. (1mk)

……………………………………………………………………………………………………………………………………………..………..

……………………………………………………………………………………………………………………………………………………….

ANSWER EITHER QUESTION 7 OR 8 IN THE SPACES PROVIDED AFTER THE QUESTIONS.

7. Describe how human skin is adapted to its function. (20mks)

8. (a) Describe the adaptation of floating water lily leaf to its photosynthetic function. (10mks)

(b) Describe the activities that take place in the chloroplast of growing plants. (10mks)

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PROJECTION NO. 54

Name……………………………………………………………………………………………. Index No…………………/…….

School………………………………………………………………………….………………… Date ………………………….…

Candidate’s Signature………………………

231/2

BIOLOGY

(THEORY)

Paper 2

Time: 2 Hours


• This paper consists of two sections A and B.

• Answer ALL questions in section A

• Answer question 6 (compulsory) and either question 7 or 8 in section B.

For Examiner’s Use Only

Section Question Maximum score Candidate’s score

A 1

2

3

4

5

8

8

8

8

8

B 6

7

8

20

20

20

Total Marks 80

of 744



Answer all questions in this section.

1. During an ecological study, students collected and marked 120 ants and released them. After

48 hours, the students captured another 90 ants, 20 of which had been marked previously.

(a) How many ants were there in the compound? Show your working. (3mks)

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(b) What are the limitations of this method in sampling animal populations. (4mks)

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(c) State two other methods which could be used to determine the population. (1mk)

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2. In an experiment to investigate the action of pepsin on egg albumen, equal amount of

paper were added to equal amount of egg albumen in different test –tubes. The test-tubes

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were placed in water bath at different temperature. The graph below shows the time taken

for the enzymes to digest protein at each temperature.

(a) What is the optimum temperature for enzymes? (1mk)

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(b) Account for the time taken to digest egg albumen at 600C. (2mks)

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(c) With reasons name the form in which the enzyme pepsin is secreted. (2mks)

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(d) State three other factors that affect enzyme controlled reactions. (3mks)

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3. The chart below represents the results of successive cross, starting with red-flowered

Plants and write flowed plants and in which both plants are pure breeding.

Parental genotype: Red Flowers x White Flowers

First filial generation

Selfed

Second filial generation

3 Red flowers : 1 White flower

(a) What are the parental genotypes? Use letter R to represent the gene for Red flower

colour and r for white colour. (2mks)

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(b) (i) What was the colour of the flowers in the first filial generation? (1mk)

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(ii) Give a reason for your answer (1mk)

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(c) If 480 red flowered plants were obtained in the second filial generation, how

Many F2 plants had white flowers? Show your working. (4mks)

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4. (a) State the meaning of apical dominance in plants (1mk)

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(b) Name the hormone associated with apical dominance. (1mk)

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(c) What is the importance of apical dominance? (1mk)

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(d) Briefly describe the effects of the following plant growth hormones

(i) Gibberellins (2mks)

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(ii) Abscisic Acid (3mks)

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5. The diagram below represents a transverse section of a leaf.

(a) (i) State the habitat of the plant from which the leaf was obtained. (1mks)

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(ii) Give two reasons for your answer in (a) (i) above. (2mks)

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(b) How does the part labelled B adapt the plant to its habitat (1mk)

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(c) Smokers are always at a high risk of suffering from respiratory infections.

Explain (3mks)

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(d) What structures are used for gaseous exchange in plants found in marine water? (1mk)

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Answer question 6 (compulsory) in the spaces provided and either


6. Carbohydrates used during respiration and those formed during photosynthesis by a

certain plant was measured over a period of 24 hours at an interval of 3 hours

Time of day 12AM 3AM 6AM 9AM 12PM 3PM 6PM 9PM 11PM

Carbohydrates formed

during photosynthesis

(mg)

0 0 5 30 60 30 5 0 0

Carbohydrates used

during respiration (mg)

10 10 10 10 10 10 10 10 10

Using the same axes,

(a) Plot a graph of carbohydrate formed during photosynthesis and carbohydrate used during

respiration against time. (7mks)

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(b) Calculate the net carbohydrate formed by the plant. (2mks)

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(c) At what time of the day do the light compensation points occur? (2mks)

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(d) Account for the shape of graph on carbohydrates.

(i) Between 12.00a.m and 3a.m. (2mks)

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(ii) Between 3.00a.m to 12.00 noon. (2mks)

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(e) How could foggy weather influence the net amount of carbohydrates formed

over the 24 hour period? (1mk)

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(f) Give other external factors apart from temperature and light intensity that

influence the rate of photosynthesis. (2mks)

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(g) In which form are carbohydrates stored in

(i) Plant bodies. (1mks)

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(ii) Fungi (1mk)

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7. (a) Define natural selection. (2mks)

(b) Natural selection brings about adaptation of a species to the environment.

Discuss. (18mks)

8. Discuss the adaptations of seeds and fruits to dispersal. (20mks)

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of 744


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PROJECTION NO. 55

NAME:……………………………………………………… INDEX NO:…………………………

SCHOOL:………………………………………………….. DATE:………………………………. SIGN:………………………………..

232/2

BIOLOGY

PAPER 2

THEORY

TIME: 2 HOURS


1. Write your name and Index number in the spaces provided.

2. Sign and write the date of examination in the spaces provided

3. This paper consists of two sections A and B

4. Answer all the questions in section A in the spaces provided.

5. In section B answer question 6 ( Compulsory) and either question 7 and 8 in the spaces provided after

question 8.


SECTION QUESTION MAXIMUM

SCORE

CANDIDATE

SCORE

A 1 8

2 6

3 10

4 8

5 8

B 6 20

7 20

8 20

TOTAL 80

of 744


1. a) Define the term cell physiology (1mk)

..................................................................................................................................................................

..................................................................................................................................................................

b) Two pieces of leaf petioles were cut as shown in the diagram below, then each piece placed

in solution of different concentration.

i) What physiological process was being investigated in this experiment? (1mk)

..................................................................................................................................................................

..................................................................................................................................................................

ii) Suggest the type of solution piece B was placed (1mk)

..................................................................................................................................................................

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iii) Explain the appearance of piece A after 15 minutes (3mks)

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c) In land plants, water logging slows down the uptake of certain minerals. Suggest a reason for

this. ( 2mks)

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2. The figure below is a simplified diagram of mammalian circulatory system. Study it and answer the


a) Explain why the level of blood sugar in vessel 3 would be higher than that in vessel 1. during

fasting. (2mks)

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b) Name the vessel that has the highest concentration of urea among vessels labeled. 1,2 and 3

(1mk)

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c) In what ways does blood vessel 1 differ from most of the other blood vessels in the body?

(1mk)

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d) Name the nutrients that is only transported in small quantities in vessels 1 following absorption.

(1mk)

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e) Why is it necessary that blood from digestive tract pass through the liver before entering the

general circulation. ( 1mk)

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3. A Pure – line pea plant with green pods was crossed with a pure – line plant with yellow pods.

All F1 plants had green pods out of 1160 F2 plants, 856 had green pods and 304 had yellow pods.

a) i) Identify the dominant and the recessive genes. (1mk)

..................................................................................................................................................................

..................................................................................................................................................................

ii) Using letter G to represent dominant gene and g to represent recessive gene, work

. out the phenotype of the F1 generation.

..................................................................................................................................................................

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b) Showing your working, state the number of plants with; (3mks)

i) Recessive genes;

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ii) Dominant genes;

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iii) Heterozygous genes;

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c) i) What is sickle cell Anemia? (1mk)

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ii) State one problem faced by people suffering from sickle cell anemia? (1mk)

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4. The graphs below show the changes in mean dry mass of endosperm, embryo and total mass of

germinating maize.

Account for the ;

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a) Decrease in the dry mass of endosperm from day 1 to day 9 (4mks)

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b) Increase in dry mass of embryo from day 1 to day 9 (1mk)

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c) Decrease in total mass upto day 6. (1mk)

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d) Increase in total mass after day 6 (2mks)

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questions that follow

.

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a) Name the structure labeled H and J. (2mks)

H

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J

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b) State how the structure labeled H,M and N are adapted to their functions. (3mks)

H

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M

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N

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c) State what would happen if the structure labeled K was completely damaged. (1mk)

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d) Name the fluid contain in structure N. (1mk)

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e) Apart from hearing, state the other role performed by the human ear. (1mk)

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SECTION B ( 40 MKS)

Answer question 6 ( compulsory) and either question 7 or 8 in the space provided after question 8.

6. In an experiment to investigate certain processes in a given plant species, the rate of carbon (iv) Oxide

released and intake were measured over a long period of time. The results of the investigation were

as shown below.

Time of the day ( Hours) 6 8 10 12 14 16 18 20 22 24

Volume of carbon (iv) Oxide

Consumed (mm3/ min)

10 43 69 91 91 50 18 0 0 0

Volume of Carbon (iv) Oxide

released (mm3/ Min)

38 22 10 3 3 6 31 48 48 48

a) On the same axes draw graphs of volume of carbon (iv) oxide consumed and released against

time. (7mks)

b) Name the chemical process changes represented by;

i) Carbon (iv) Oxide consumed (1mk)

……………………………………………………………………………………………….………………………………

……………………………………………………………………………………………………………………………….

ii) Carbon (iv) Oxide released (1mk)

…………………………………………………………………………………………………………………………………

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c) Account for the shape of the curve for

i) Carbon (iv) oxide consumed (3mk)

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ii) Carbon (iv) Oxide released (3mk)

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d) i) What is meant by compensation point (1mk)

………………………………………………………………………………………………………………………………………………………..

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ii) From the graph, find the time of the day when the plant attained compensation point. (2mks)

………………………………………………………………………………………………………………………….…………………………………….

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d) Explain how temperature affects the rate of carbon (iv) oxide consumption in the plant. (2mks)

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7. a) What is meant by natural selection (3mks)

b)Describe how natural selection brings about adaptation of species to its environment. (17mks)

8. a)Describe the characteristics and functions of the three types of muscle found in the

mammalian body. (11mks)

b) Explain how the various components of blood are adapted to perform their functions. (9mks)

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PROJECTION NO. 56

Name……………………………………………………………………… Index No…………………….

School…………………………………………………………………….. Sign………………………….

Date………………………….

231/2

BIOLOGY

(THEORY)

PAPER 2

TIME: 2 HOURS






question 8.

FOR EXAMINER’S USE ONLY:-


A 1

2

3

4

5

08

08

08

08

08

B 6

7

8

20

20

20

TOTAL

SCORE

80

SECTION A (40MARKS)

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1. A freshly obtained dandelion stem measuring 5cm long was split lengthwise to obtain two similar

pieces. The pieces were placed in solutions of different concentrations in Petri dishes for 20 minutes.

The appearance after 20 minutes is as shown.

(a) Account for the appearance of the pieces in solutions L1 and L2 (6mks)

L1

………………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………………..

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………………………………………………………………………………………………………………………………………………………………

L2

………………………………………………………………………………………………………………………………………………………………

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(b) State the significance of biological process involved in the experiment. (2mks)

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2. (a) Give three reasons in each case why support is necessary in

(i) Plants (3mks)

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(ii) Animals (3mks)

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(b) Why is movement necessary in animals? (2mks)

(i)

………………………………………………………………………………………………………………………………………………………………

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(ii)

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3. In maize the gene for purple colour is dominant to the gene for white colour. A pure

bleeding maize plant with purple grains was crossed with a heterozygous plant.

(a)

(i) Using letter G to represent the gene for purple colour, work out the

genotypic ratio of the offspring. (5mks)

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(ii) State the phenotype of the offspring. (lmk)

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(b) What is genetic engineering? (lmk)

………………………………………………………………………………………………………………………………………………………………

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(c) What is meant by hybrid vigour? (lmk)

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4. (a) Distinguish between pyramid of numbers and pyramid of biomass. (2mks)

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(b) Give three reasons for loss of energy from one trophic level to another in a food

chain. (3mks)

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(c) Describe how the belt transect can be used in estimating the population of a

shrub in a grassland. (3mks)

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5. (a) What is meant by the terms?

(i) Epigynous flower? (lmk)

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(ii) Staminate flower? (lmk)

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(b) Name the essential parts of a flower. (2mks)

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(c) How are the male parts of a wind pollinated flower adapted to their functions? (4mks)

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SECTION B (4OMARKS)

Answer question 6 (compulsory) in the spaces provided and either question 7 or 8 in the spaces


6. In an experiment to determine the effect of ringing on the concentration of sugar in phloem, a ring of

bark from the stem of a tree was cut and removed. The amount of sugar in grams per 16cm3 piece of

bark above the ring was measured over a 24hour period. Sugar was also measured in the bark of a

similar stem of a tree which was not ringed. The results are shown in the table below.

Time of the day Amount of sugar in grams per 16cm3 piece of bank

Normal stem Ringed stem

0645 0.78 0.87

0945 0.80 0.91

1245 0.81 1.01

1545 0.80 1.04

1845 0.77 1.00

2145 0.73 0.95

0045 0.65 0.88

(a) Using the same axes, plot a graph of the amount of sugar against time. (6mks)

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(b) At what time was the amount of sugar highest in the-:

(i) Ringed stem. (lmk)

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(ii) Normal stem. (lmk)

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(c) How much sugar would be in the ringed stem if it was measured at 0345 hours? (lmk)

………………………………………………………………………………………………………………………………………………………………

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(d) Give reasons why there was sugar in the stems of both trees at 0645 hours. (2mks)

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(e) Account for the shape of the graph for the tree ringed stem between

(i). 0645 hours and 1545 hours (3mks)

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(ii) 1545 hours and 0045 hours (2mks)

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(f) Name the structures in the phloem that are involved in the translocation of

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sugars. (2mks)

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(g) Other than sugars name two compounds that are translocated in phloem. (2mks)

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7. (a) State four characteristics of gaseous exchange surfaces. (4mks)

(b) Describe the mechanism of gaseous exchange in a mammal. (l6mks)

8. (a) What is meant by the term digestion? (2mks)

(b) Explain the role of bile in the digestion of food. (4mks)

(c) Describe the digestion of protein in the human body. (l4mks)

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PROJECTION NO. 57

NAME…………….…………………………… INDEX NO…………………………..…..

SCHOOL ………………………………................... SIGNATURE………….…..…..…

DATE…………………………….…………

231/2

BIOLOGY

PAPER 2

2HRS


231/2

BIOLOGY

PAPER TWO

Instructions to candidates;

❖ Write your name, index number and name of your school in the spaces provided

❖ This paper consists of two parts A and B.

❖ Answer ALL questions in section A in the spaces provided

❖ In section B answer questions 6 (compulsory) and either question 7 or 8 in the spaces provided after

question 8.

For examiners only


A

1 8

2 8

3 8

4 8

B

5 8

6 20

7 20

8 20

Total score 80

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SECTION A (40MARKS)


1. The diagram below illustrates blood circulation in certain organs in humans.

a) Name the part labeled A. (1mrk)

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b) Name the blood vessels labeled B and F. (2mks)

B................................................................................................................................

F............................................................................................................................ ......

c) State how the composition of blood in vessel E differs from that in vessel D. (3mks)

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E D

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d) Explain the role of bile in the process of digestion. (2marks)

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2. The diagram below represents a section through a leaf of a terrestrial plant.

a) Name the structures labeled S, X, Y and V (2marks)

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b) State the roles of each of the parts labeled V and W. (2mrks)

V

........................................................................................................................ ........................

............................................................................................................................................. ..

W

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c) State two ways in which structures labeled X and Y are adapted to their functions. (4mks)

X

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Y

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3. A common species of rats has individuals with white, black or grey coats. During a study a rat

with white coat was crossed with a rat with black coat. Both parents were pure lines. All the

offspring in F1 generation had grey coats. Using letter B to represent the gene type for black

coat and W for white coat, answer the questions that follow.

a) Suggest a reason to explain why there were no white or black rats in the F1

generation. (1mark)

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…………………………………………………………………………………………………………………………………….

b) The F1 offspring were selfed to get F2 generation. Work out the phenotypic ratio of

F2. Show your working. (5marks)

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c) Name one trait in human beings that is determined by multiple allele. (1mrk)

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d) Name one genetic disorder affecting the human eye. (1mrk)

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4. During an ecological field work, a group of students caught 240 grasshoppers, marked them

and then released them back to the study area. After one day they caught 160 grasshoppers

and found that 40 were marked. Using the formula;

P =F.C.M X S.C

S.C.M

Where P =Total population

F.C.M = First capture marked

S.C = Second capture

S.C.M = Second capture marked

a) Work out the total population of the grasshoppers in the study area. (2mrk)

..........................................................................................................................................

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b) b) Identify the method used to capture the grasshoppers. (1mrk)

............................................................................................................................. .............

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c) Name the instrument and chemical the students used to collect and mark the

grasshoppers. (2mrks)

i) Instrument for collection

................................................................................................................................................

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ii)Chemical for marking

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d) State any one assumption the students made during the field work. (1mrk)

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. …………………………………………………………………………………………………….................................

e) The students observed the organisms and placed them into their correct phylum and

class. Name the phylum and class.

i) Phylum..................................................................................................................

ii) Class .....................................................................................................................

5. The diagram below shows a transverse section of the spinal cord.

a) Name the parts labeled K and N. (2mrks)

K

............................................................................................................................. .............

N

............................................................................................................................. .............

b) Describe briefly how the impulse transmission occurs through the structures in the

diagram (3mrks)

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c) State three differences between simple and conditioned reflex actions. (3mrks)

Simple reflex Conditioned reflex

i)

ii)

iii)

SECTION B (40MARKS)

Answer questions 6 (COMPULSORY) and Either question 7 or 8 in the spaces provided after

the question 8.

6. Rice seeds were soaked overnight. Fresh mass and dry mass of a sample of 20 seeds was

obtained and recorded in the table. The rest of the seeds were planted in a tray that had soil

and well watered daily. Twenty of the seeds/seedlings were removed from the soil every two

days for two weeks. Their fresh and dry mass were taken and recorded in the table as shown

below.

Time in days Fresh mass in (g) Dry mass in (g)

0 14.0 4.0

2 18.0 3.5

4 24.5 2.5

6 32.0 1.5

8 38.5 2.0

10 41.0 3.0

12 43.0 4.5

14 45.0 6.0

a) Using the same axes, plot two graphs to represent changes in fresh

and dry mass over the two –week period (7mrks)

b)

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c) .What would be the fresh and dry mass of the seedlings at day 9. (2mrks)

i) Fresh mass

........................................................................................................................

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ii) Dry mass

........................................................................................................................

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d) Account for the change in fresh mass and dry mass between day 0 and day 6.

(4mrks)

i) Fresh mass

........................................................................................................................

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ii) Dry mass

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e) Explain the change in dry mass from day 8 (2mrks)

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f) Explain why a sample of 20 seeds was used instead of one seed. (2mrks)

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g) State one factor within and one factor outside the seed that cause dormancy.

(2mrks)

…………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………

i) Within the seed

....................................................................................................................

……………………………………………………………………………………………………………….

ii) Outside the seed

.....................................................................................................................

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h) Give one characteristic of a meristematic cell (1mrk)

....................................................................................................................................

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7. Explain the evidences of organic evolution in life forms. (20mrks)

8. Describe how gaseous exchange takes place in terrestrial plants. (20mrks)

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PROJECTION NO. 58

Name……………………………………………… Index No. …………………….

School …………………………………………… Date……. …………………….

Sign……. …………………….

231/2

BIOLOGY

PAPER 2

Time: 2 Hours


• This Paper consists 2 sections A and B.

• Answer all questions in section A in the spaces provided

• In section B, answer questions 6 ( compulsory) and either questions 7 or 8 in the spaces after questions 8..


SECTION Questions Maximum Score Candidates Score

A

1 8

2 8

3 8

4 8

5 8

B

6 20

7 20

8 20

TOTAL SCORE 80

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SECTION A 40 MARKS

1. The diagram below is a longitudinal section of an organ in mammals

a) Name the organ (1mk)

…………………………………………………………………………………………………………..………………………………….

……………………………………………………………………………………………………………………………..……………….

b) Identify the parts R and S (2mks)

…………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………..……………………….

……………………………………………………………………………………………………………………………………………..

c) i) State two differences in the structure above found in the deserted- rat and fish

(3mks)

……………………………………………………………………………………………………………………………………………..

……………………………………………………………………………………………………………………………………………..

……………………………………………………………………………………………………………………………………………..

……………………………………………………………………………………………………………………………………………..

…………………………………………………………………………………………………………………………………………….

ii) Account for the difference stated above. (2mks)

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d) Name the gland associated with the secretion of aldorsterone hormone. (1mk)

…………………………………………………………………………………………………………………………………………….

………………………………………………………………………………………………………………………………………………….

2. a) What is the economic importance of anaerobic respiration in industry. (3mks)

…………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………….…………………………………………………………………………….

………………………………………………………………………..………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………….

b) Explain what happens in the two phases of aerobic respiration. (5mks)

……………………………………………………………………..……………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………….

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3. The diagram below shows three different types of neurons along a reflex arc.

a) Identify the Neuron labeled 1,2 and 3. (3mks)

………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………

b) Using arrows show the direction of impulse transmission on the diagram. (1mk)

c) Name the part where the cell body of neurons 1 and 2 are located. (2mks)

………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………..

……………………………………………………………………………………………………………………………………………..

d) Describe the transmission of impulses across the part labeled T.

…………………………………………………………………………………………………………………………………………………

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…………………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………………

4. In an experiment, a variety of garden peas have a smooth seed coat was crossed with a variety with a

wrinkled seed coat. All the seeds obtained in the F1, had a smooth seed coat

The F1 generation was selfed. The total number of F2 generation was 7324.

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a) Using appropriate letter symbols in a punnet square, work out the genotypes of the F1

generation. (4mks)

b) From the information above, work out the following for the F2 generation

(i) Genotypic ratio (2mks)

………………………………………………………………………………………………………………….….……………………….

…………………………………………………………………………………………………………………………………..………….

(ii) Phenotypic ratio (1mk)

…………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………….

(iii) Wrinkled number (1mk)

…………………………………………………………………………………………….……………………………………………….

…………………………………………………………………………………………………………….……………………………….

5. The diagram below illustrate the first stage in the energy flow in the ecosystem

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a) Identify (i) organelles responsible for activity in D.

(i) in D (1mk)

……………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………

(ii) Gas X (1mk)

…………………………………………………………………………………………………………….…………….

……………………………………………………………………………………………………………………………….

b) Suggest the roles played by each of the following in the process illustrated above.

i) Light energy (1mk)

…………………………………………………………………………………………………………………….…………….

………………………………………………………………………………………………………………………………….

ii) Water (1mk)

…………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………..

iii) Carbon (II) oxide (1mk)

……………………………………………………………………………………………………………………………………………….

………………………………………………………………………………………………………………………………………………

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DAY WIDTH OF HEAD LENGHT

Mm Femur (mm)

1 3.0 7.0

2 3.5 7.5

3 4.0 8.0

4 4.0 8.0

5 4.0 8.0

6 4.0 9.2

7 4.0 10.5

8 4.0 12.0

9 4.7 12.0

10 5.0 12.0

11 5.0 12.0

12 5.0 12.0

13 5.0 12.0

14 5.0 12.0

15 5.0 13.3

16 5.0 14.8

17 5.7 16.4

18 6.4 18.0

19 7.0 18.0

20 7.6 18.0

21 7.6 18.0

22 7.6 18.0

23 7.6 18.0

24. 7.6 18.0

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c) Give three ways in which the carbohydrates produced in the organelles at D is utilized in the

plants. (3mks)

………………………………………………………………………………………………………………………………………………..

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……………………………………………………………………………………………………………………………………………….

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SECTION B: 40 MARKS

6. The following data are results from an observation and measurement of daily growth in an

organism over a period of 24 days of its development

a) Using a suitable scale draw graphs of width of head and length of femur against time on the

same axis. (8mks)

b) i) Name the growth pattern represented by the graph. (1mk)

……………………………………………………………………………………………….……………………………………………………………

…………………………………………………………………………………………………………………………………………………………….

ii) With reference to your graph, identify the phylum to which the organism belongs.

Give reasons for your answer. (2mks)

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………………………………………………………………………………………………………………………………..……………………………

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c) Account for the length of hind femur between

(i) day 3 and day 7 (2mks)

………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………

(ii) day 7 and day 10 (2mks)

……………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………..

……………………………………………………………………………………………………………………………………………..

d) State two hormones involved in the growth pattern represented by the graphs . (2mks)

……………………………………………………………………………………………….……………………………………………………………

………………………………………………………………………………………………………………………………………………….…………

……………………………………………………………………………………………………………………………………………………………..

e) State two advantages of metamorphosis in organisms. (2mks)

……………………………………………………………………………………………….……………………………………………………………

………………………………………………………………………………………………………………………………………………….…………

…………………………………………………………………………………………………………………………………………………………….

7. Explain how the various activities of man have caused air pollution. (20mks)

8. a) What are enzymes? (2mks)

b) State the properties of enzymes (6mks)

c) Discuss the factors that affect the rate of enzyme – catalysed reactions (12mks)

……………………………………………………………………………………….……………………………………………………………………

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PROJECTION NO. 59

Name………………………………………………………………………………………………….……. Index No…………………/……….….

School………………………………………………………………………………..…… Date ………………………………….….…

Candidate’s Signature……………………………………

231/2

BILOGY

PAPER 2

Time: 2 Hours


1. Write your name and Index Number in the spaces provided above.

2. Sign and write the date of the examination in the spaces provided above.

3. This paper consists of TWO sections; A and B.

4. Answer all the questions in section A in the spaces provided.

5.In section B answer questions 6 ( Compulsory) and either question 7 or 8 in


.

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SECTION A – Answer all the questions in this section.

1. In an experiment to investigate the rate of reaction indicated by the equation.

C12H22O11 C6H12O6 + C6H12O6

Sucrose Fructose Glucose

It was found out that for products fructose and glucose to form, substance “K” was needed.

Temperature was maintained at 37oC.When substance “L” was added, reaction slowed and then

stopped.

(a) Suggest identity of the substances (2mks)

K

…………………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………………

L

…………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………….

(b) Other than temperature, state three factures that increase the rate of reaction. (3mks)

………………………………………………………………………………………………………………………………………………….……

……………………………………………………………………………………………………………………………………………………..

………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………..

(c) Explain how substance “L” slowed the rate of reaction. (2mks)

……………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………………..

(d) What type of reaction is represented by the equation above? (1mk)

…………………………………………………………………………………………………………………………………………………………..

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2. (a) Give the differences between the following structures in wind and insect pollinated

flowers. (6mks)

Structure Insect pollinated flower Wind pollinated flower

(i)Anther

(ii)Stigma

(iii)Pollen grain

(b) State two mechanisms that hinder self pollination in flowering plants

…………………………………………………………………………………………………………………..……………………………….…………

………………………………………………………………………………………………………………………..……………………………………

3. Study the diagram below and answer the questions that follows.

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(a) Identify part labeled Q. (1mk)

………………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………………..

(b) (i) What type of response is shown above? (1mk)

………………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………………..

(ii) What is the importance of the above response? (1mk)

……………………………………………………………………………………………………………………………………………………………..

…………………………………………………………………………………………………………………………………………………………….

(c) Explain how the response exhibited by the part Q occurs. (4mks)

……………………………………………………………………………………………………………………………………………………………..

……………………………………………………………………………………………………………………………………………………………..

…………………………………………………………………………………………………………………………………………………………….

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(d) Name the plant hormone that is responsible for this response. (1mk)

………………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………………..

4. In a certain species of flies, the genotypes of pure breeds RR and rr, a cross was made between

the two genotypes. When sprayed with an insecticides ,it was found that it would only kills flies

of genotype rr.

(a) Perform a cross to show the results of a cross between two heterozygote flies. (3mks)

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(b) What percentage of flies would be killed by the insecticides show your working. (2mks)

(c) Explain why the insecticides kills only flies of genotype rr. (2mks)

……………………………………………………………………………………………………………………………………………………………

……………………………………………………..……………………………………………………………………………………………………

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(d) What is an allele? (1mk)

……………………………………………………………………………………………………..………………………………………………………

………………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………………

5. The flow chart below shows blood transfusion pathway.

(a) What five conclusions can you draw from the above flow chart? (5mks)

……………………………………………………………………………………………………………………………………….……………………

…………………………………………………………………………………………………………………………………………………….………

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……………………………………………………………………………………………………………………………………..………………………

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(b) Why is the knowledge of blood groups necessary before blood transfusion? (1mk)

……………………………………………………………………………………………………………………………………………………………..

……………………………………………………………………………………………………………………………………………………………

(c) A part from knowledge of blood groups state two precautions that must be observed during

blood transfusion. (2mks)

……………………………………………………………………………………………………………………………………………………………..

………………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………………..

…………………………………………………………………………………………………………………………………………………………….

SECTION B(40 MARKS)

Question 6 is compulsory. Then answer either 7 or 8.

7. A person had gone for 24 hours without food. Then he was served with a well balanced meal after

which the concentration of glucose and amino acids in the blood were determined every one hour for

the next 8 hours after the meal, the concentration were measured as blood passed through the

hepatic portal vein and hepatic vein.

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The results were as shown in the data below.

Time in hours Concentration of Glucose & amino Acids in blood (Mg/100 cm3 of blood)

HEPATIC PORTAL VEIN HEPAT IC VEIN

GLUCOSE AMINO ACIDS GLUCOSE AMINO ACIDS

0

1

2

3

4

5

6

7

8

79

79

160

140

120

100

90

90

90

1.0

1.0

1.0

4.0

6.0

5.0

2.0

1.0

1.0

85

85

110

100

90

90

90

90

90

1.0

1.0

1.0

3.0

3.0

2.0

1.0

1.0

1.0

(a) On the same axis plot graphs of glucose concentration in hepatic portal vein and hepatic vein


(b) Account for the difference in blood sugar level in hepatic portal vein and hepatic vein.

(i) Between 0-1 hours. (4mks)

……………………………………………………………………………………………………………………………………..……………………

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(ii) Between 2-4 hours (5mks)

………………………………………………………………………………………………………………………………………………………………

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………………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………………

(c) (i) Give one reason that delayed increase in amino acids concentration in hepatic

portal vein. (1mk)

………………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………………

(ii) Account for the difference in concentrations of amino acids in hepatic portal vein

and hepatic vein between 3rd -6th hours (2mks)

………………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………………

(d) Name the enzyme that completes fat digestion in man (1mk)

……………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………………...

7. A student ate lean meat for break fast, Explain fully how the meal eventually becomes part of the

body tissue. (20mks)

8. (a) With aid of a large labeled diagram describe the process of fertilization in a flowering

plant. (14mks)

(b) How does the process above differ from that in Bryophytes. (6mks)

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PROJECTION NO. 60

Name…………………………………………………………………………… Index No……………………………………………………..…..

School………………………………………………………………………….. Date…………………………………………………………………….

Candidate’s signature…………………….……………………..

231/2

BIOLOGY

Paper 2

Time 2Hours













A 1

2

3

4

5

08

08

08

08

08

B 6

7

8

20

20

20

TOTAL SCORE 80

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Answer All questions in this section

1. Two herbivorous mammalian species were introduced into an ecosystem at the same time

and iin equal numbers. The graph below represents their populations during the first seven

years. Study the graph and answer the questions that follow.

a) i) Which species has a better competitive ability? (1 mark)

....................................................................................................................................................

....................................................................................................................................................

ii) Give reason for your answer (l mark)

....................................................................................................................................................

....................................................................................................................................................

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b) Account for the shape of the curve of species A between

i) One year and three years (2 marks)

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ii) Three years and seven year (2 marks)

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c) A natural predator for species A was introduced into the ecosystem.

With a reason state how the population of each species will be affected(2 marks)

....................................................................................................................................................

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....................................................................................................................................................

2 The chart below represents the result of successive crosses, staring with red flowered

plants and white flowered plants in which both plants are pure breeding

a) What were parental genotype ? Use letter R to represent the gene for red colour

and r for white colour ( l mark)

................................................................................................................................................................

.................................................................................................................................................................

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b) i) What was the colour of the flowers in the first filial generation? ( l mark)

....................................................................................................................................................

....................................................................................................................................................

ii) Give a reason for your answer in b (i) above (l mark)

....................................................................................................................................................

....................................................................................................................................................

....................................................................................................................................................

c) lf 480 red flowered plants were obtained in the second filial generation, how many

F2 plants had white flowers? Show your working (5 marks)

3. A form 1 student placed a red blood cell in a solution and made an observation as follows.

Start of experiment/ end of experiment

a) i) In what solution was the red blood cell paced? (l mark)

....................................................................................................................................................

....................................................................................................................................................

ii) Explain the observation above (2 marks).

....................................................................................................................................................

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b) If the red blood cell was replaced by a plant cell what would be the observation

(2 marks)

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c) Why don’t the red blood cell undergo the same changes as above while in the

body. (3 marks)

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.................................................................................................................................................................

................................................................................................................................................................

................................................................................................................................................................

5. The figure shows changes that take place during menstrual cycle in human

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a) Name the hormone whose concentrations are represented by curves F and G (2 marks)

....................................................................................................................................................

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b)State the effects of the hormones named in (a) above on the lining of the uterus

(2 marks)

....................................................................................................................................................

....................................................................................................................................................

...................................................................................................................................................

...................................................................................................................................................

....................................................................................................................................................

c) i) Name the hormone which is released by the pituitary gland in high

concentration on the 14th day of the menstrual cycle (l mark)

....................................................................................................................................................

....................................................................................................................................................

....................................................................................................................................................

ii) State two functions of the hormone named in (c) (i) above (2 marks)

....................................................................................................................................................

....................................................................................................................................................

....................................................................................................................................................

. ...................................................................................................................................................

....................................................................................................................................................

d) State the fertile period during the menstrual cycle ( 1 mark)

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5. The diagram below represents a bone obtained from a mammal

a) Name the bone ( 1 mark)

....................................................................................................................................................

....................................................................................................................................................

....................................................................................................................................................

b) Name the:

i) Bone which articulate with the bone named in (a) above at the cavity labeled K;( 1mark)

....................................................................................................................................................................

....................................................................................................................................................................

................................................................................................................................................................

ii) Joint formed by the two bones (1 mark)

....................................................................................................................................................................

...................................................................................................................................................................

..................................................................................................................................................................

c) State the function of the part labeled J

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d) Explain how the pelvic girdle is adopted to its function (4 marks)

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Section B

Answer question six in the spaces provided and either question 7 or 8 in the spaces provided

after question8

9. An experiment was carried out to investigate the nutritional value of two dry powder

animals feeds X and Y over a period of six months. Twenty 5 month’s old castrated

goats were use. The goats were divided into two equal groups A and B.

The animal’s in group A were fed on feed X throughout the experiment while those of

group B were fed on feed Y.

The feeds were supplemented with dry hay and water. The average body weight of

each group of goats and the weight of the dry powder feeds were determined and

recorded each month. The faeces produced by each group was dried and weighed and

the average dry faecal output per month was also recorded. The results are as shown

below.

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GROUP A GROUP B

Months since

commencement

of the

experiment

Average

total

weight of

goats(Kg)

Average

weight

of total

feed(Kg)

Average

monthly

dry faecal

output(Kg)

Average

total

weight of

goats(Kg)

Average

weight

of total

feed(Kg)

Average

monthly

dry faecal

output(Kg)

0 20.4 26.7 10.5 20.5 35.4 16.5

1 22.5 27.5 10.7 19.5 34.3 17.7

2 24.5 25.8 10.3 19.0 35.2 17.2

3 26.3 18.5 8.8 18.5 36.1 17.5

4 28.0 16.6 7.2 17.1 36.0 16.9

5 29.4 16.3 6.0 16.3 35.8 16.8

6 29.5 16.1 5.6 15.6 35.5 16.6

a)i)What is the relationship between the amount of feed and the faecal output(2 marks)

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ii) Work out the average increase in weight for the animal’s in group A during:


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The last two months

. ...................................................................................................................................................

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(4 marks)

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iii) Account for the average increase weight in goats in group A during:


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The last two months

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(4 marks)

iv) Which of the two feeds is more nutritious? Give reason for your answer

(2 marks)

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b) Explain the digestion of lipids in humans (8 marks

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7 a) Describe how semicircular canals perform their functions (8 marks)

b) Describe how the cervical, lumbar and sacral vertebrae are suited to their functions

(l2 marks)

8 a) State four characteristics of gaseous exchange surfaces. (4 marks)

b) Explain the theories for opening and closing of the stomata (16 marks)

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. PROJECTION NO. 61

Name…………………………………………………………………………………. Index No……………………………..

School…………………………………………………………………………….…… Candidate’s sign…………………….. .

Date………………………………….

231/2

BIOLOGY

Paper 2

(THEORY)

2 Hours


10. write your name and admission number in the spaces provided 11. Sign and write the date of examination in the spaces provided above 12. this paper consist of TWO section A and B 13. Answer ALL the questions in section A in the spaces provided 14. In section B answer question 6 (compulsory and either question 7 or 8 in the spaces provided

after question 8. For examiners use only:

SECTION QUESTION MAX.SCORE CANDIDATES SCORE

A 1

2

3

4

5

8

8

8

8

8

B 6

7

8

20

20

20

TOTAL 80

of 744


SECTION A (4OMKS)


1. ( a) Define

i) Osmosis (lmk)

………………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………….…

ii) Haemolysis (lmk)

………………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………………

(b) State the role of active transport in plants. (2mks)

………………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………..………………………………………………………

(c) Why is oxygen important in the process of active transport? (lmk)

………………………………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………..…………………………………………………

(d) State three properties of the cell membrane (3mks)

………………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………………………….

2. In a family with four children, three were found to have normal skin pigmentation while one was an

albino. Using letter A to represent gene for normal skin pigmentation and a to represent the gene for

albinism.

(b) What are the genotypes of the parents? (2mks)

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(b) Work out the genotypes of the normal pigmented children and the albino child (5mks)

(c) What is the probability that the fifth child will be an albino? (lmk)

………………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………………..

3. The diagram below represents a food web in a terrestrial ecosystem.

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(a) Which organism has the highest number of preys (lmk)

………………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………..………………………………………

(b) Construct food chains with snakes as tertiary consumers (2mks)

………………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………………..

(c) State the trophic level occupied by hawks in the food chains constructed in b) above (lmk)

………………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………………

(d) Describe how capture — recapture method can be used in estimating the population of

fishes in a lake. (4mks)

………………………………………………………………………………………………………………………………………………………………

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4. (a) Differentiate between the mode of fertilization in higher plants and in mammals (2mks)

………………………………………………………………………………………………………………………………………………………………

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………………………………………………………………………………………………………………………………………………………………

(b) Explain the role of the following hormones in the female menstrual cycle

(i) Oestrogen (2mks)

………………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………..……………………………………………………………

(ii) Luteinizing hormone (2mks)

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(c) Give two functions of the placenta during pregnancy (2mks)

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……………………………………………………………………………………………………………………………………………………………

5. In an experiment to investigate an aspect of digestion, two test tubes P and Q were set up as show in

the diagram below.

The test tubes were left in the bath for 30 minutes. The content of each test tube was then tested for

starch using iodine solution.

(a) What was the aim of experiment? (lmk)

………………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………………

(b) What results were expected in test tube P and Q (2mks)

P………………………………………………………………………………………………………………………………..………………………….

Q…………………………………………………………………………………………………………………………………………………………..

(c) Account for the results you have given in b above in test tube P and Q (2mks)

P

………………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………………

Q

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(d) Why was the set up left at 37°C (1 mk)

………………………………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………..…………………………………

(e) Name the carbohydrate stored in (2mks)

i. Mammalian liver

………………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………………

iii. Potato tuber

………………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………………

SECTION B

Answer question 6 (Compulsory) and either question 7 or 8

6. Two sets of a pea seeds were germinated, set A was placed in normal daylight conditions in the

laboratory while set B was placed in a dark cupboard. Starting a few days later the shoots lengths

were measured twice daily and their mean lengths recorded as shown in the table below.

(b) Using suitable scale draw the graphs of the mean lengths in set A and B against time.

(b) From the graph state the mean shoot length of each set of seedling at the 66th hour (2mks)

………………………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………………

(c) Account for the difference of curve B and A (3 mks)

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(d) Explain what would happen to set up B if it were allowed to continue to grow under

conditions of darkness (4mks)

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(e) State three external conditions which should be constant for both set ups (3mks)

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………………………………………………………………………………………………………………………………………………………………

7. (a) What is reflex action (lmk)

(b) Describe what happens in the nervous system of a person who withdraws a finger from a

very hot object. (14mks)

(c) Explain what happens to a young growing seedling when exposed to unidirectional

source of light. (5mks)

8. (a) Outline the characteristics of the meristematic tissues. (5mks)

(b) Explain how different meristematic tissues contribute to growth higher plants. (l5mks)

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of 744


PROJECTION NO. 62

NAME:……………………………………………………… INDEX NO:…………………………

SCHOOL:………………………………………………….. DATE:……………………………

SIGN:………………………………..

231/2

BIOLOGY

PAPER 2

(THEORY)

TIME: 2 HOURS









A 1

2

3

4

5

8

8

8

8

8

B 6

7

8

20

20

20

TOTAL 80

of 744





(a) Identify the structure and state its functions (2mks)

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(b) (i) Name the parts labelled P and Q (2mks)

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(ii) State the role of the part labelled R (1mk)

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(c) How is the structure stated in (a) above adapted to its function (2mks)

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(d) What is the role of enzyme enterokinase in digestion? (1mk)

....................................................................................................................................................................

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2. (a) The diagram below illustrates a response exhibited by a certain plant tendril. Study and

answer the questions that follow.

(i) Identify the type of response exhibited above. (1mk)

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(ii) Explain how the response in (a) above occurs (3mks)

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(b) The diagram below represents the anterior view of a certain mammalian vertebra

(i) With a reason, identify the type of vertebra shown above (1mk)

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(ii) State the role of the parts labelled

R (1mk)

....................................................................................................................................................................

....................................................................................................................................................................

Q (1mk)

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3. (a) Define the following terms as applied in genetics

(i) Genetic engineering (1mk)

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(ii) Polyploidy (1mk)

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(b) When pure breeding red-flowered Mirabilis jalapa plant was crossed with a pure

breeding white flowered plant, the resulting plants produced pink flowers only. Using

letter R to represent the gene for red flowers, and W for white flowers;

(i) Work out the genotypes of the F2 generation (4mks)

(ii) State the phenotypic ration of the F2 plants (1mk)

……………………………………………………………………………………………………………………………………………………..

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(iii) Account for the occurrence of the pink flowered plants in the F1 generation

(1mk)

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4. (a) Name the type of circulatory system found in members of the class insecta (1mk)

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………………………………………………………………………………………………………………………………………………………..

(b) Name the blood vessels that transport blood from:

(i) Small intestines to the liver (1mk)

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(ii) Lungs to the heart (1mk)

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(c) The diagram below shows gaseous exchange in tissues


(I) To the body cells (1mk)

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(II) From the body cells (1mk)

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(ii) Which compound dissociates to release the gas named in (a)(i) above (1mk)

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(c) What is tissue fluid (2mks)

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5. (a) Explain how the following abiotic factors affect plants

(i) Wind (2mks)

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(ii) Humidity (2mks)

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(b) Explain how heavy metals in industrial effluences may accumulate in the bodies of humans to

toxic levels (2mks)

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(c) Only a small amount of food energy in herbivores is passed onto secondary consumers.

Explain (2mks)

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Answer question 6(compulsory) and either question 7 or 8

6. The mean dry weight (mg) of germinating wheat grains was worked out for a whole grain(total dry

weight),endosperm and embryo.

The means were determined at two days interval for fourteen days. The results are as tabulated

below.

Time(days) Dry weight(mg)

Endosperm Embryo Total

0

2

4

6

8

10

12

14

47

44

39

22

10

4

2

2

5

5

8

17

28

35

42

44

52

49

47

39

38

39

44

46

(a) Using the same axis ,draw graphs for dry weight of endosperm, embryo and total against time

(8mks)

(b) What was the average dry weight of embryo on day II? (1mk)

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(c) Account for the shape of the curve for

(i) Embryo from day 2 to day 12 (2mks)

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(ii) Total dry weight (gm) from day 0 to day 14 (2mks)

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(d) After how long was the dry weight of

(i) Endosperm 30g? (1mk)

....................................................................................................................................................................

....................................................................................................................................................................

(ii) Embryo 35g ? (1mk)

....................................................................................................................................................................

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(e) (i) Explain the role of water in seed germination (3mks)

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(iii) Other than water, what two environmental factors are required for seed

germination? (2mks)

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7. (a) Describe how natural selection brings about the adaptation of a species to its environment

(10mks)

(b) Discuss the economic importance of bacteria (10mks)

8. (a) Describe the methods of excretion in plants (5mks)

(b) Explain the role of hormones in the human female menstrual cycle (15mks)

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PROJECTION NO. 63

NAME: ……………………………………………………………….ADM NO: ………………

SCHOOL: ………………………………………………….STREAM: …………………………

INDEX NO: ………………………………………………………………………………………

231/2

BIOLOGY

Paper 2

2 HOURS

INSTRUCTION TO CANDIDATES

Answer ALL questions in section A. In section B answer question 6 (compulsory) and either


SECTION QUESTION MAX. SCORE CANDIDATE’S SCORE

A 1 8

2 8

3 8

4 8

5 8

B 6 20

7 20

8 20

TOTAL 80

of 744



1. A climbing plant twines around the stem of a tall tree.

(a) (i) Name the type of response exhibited by the climbing stem. (1 mark)

………………………………………………………………………………………………

………………………………………………………………………………………………

(ii) Explain how the response named in (a) (i) above takes place. (3 marks)

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(b) An experiment was carried out to investigate the response of white termites to a

certain stimulus. Ten termite were placed at the centre of glass tubing. Calcium chloride

was placed one end of the tubing and moist cotton wool at the other end as illustrated

below.

(i) What observations are made after 20 minutes? (1 mark)

………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………..

(ii) What type of response is exhibited by the termites? (1 mark)

………………………………………………………………………………………………………………………………

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(iii) What is the survival value of the above response? (1 mark)

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(iv) What is Photonasty? (1 mark)

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2. (a) What is multiple allelism? (1 mark)

………………………………………………………………………………………………………………………………

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(c) A pure breeding black male mouse was mated with a pure breeding brown female

mouse. All the offspring had black coat colour.

(i) Explain the appearance of black coat colour in the offspring. (1 mark)

………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………..

……………………………………………………………………………………………………………………………

(ii) If the black parental mouse was mated with a mouse that is heterozygous for coat

colour, work out the genotypic ratio of offspring. Show your working.(4 marks)

………………………………………………………………………………………………………………………………

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(iii) State two disorders in human beings that are as a result of chromosomal mutation.

(2 marks)

………………………………………………………………………………………………………………………………

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3. (a) i) What is meant by the term biological control? (1 mark)

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(ii) Give an example of biological (1 mark)

………………………………………………………………………………………………………………………………

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(b) (i) What is eutrophication? (3 marks)

………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………..

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(ii) What are the effects of eutrophication? (3 marks)

………………………………………………………………………………………………………………………………

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4. The diagram below represents a transverse section of a plant organ.

(a) From which plant organ was the section obtained. (1 mark)

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(b) Give two reasons for your answer in (a) above. (2 marks)

………………………………………………………………………………………

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(c) Name the parts labeled J, K and L (3 marks)

J: ……………………………………………………………………………………………….……………………

K: ………………………………………………………………………………………………………….……….

L: …………………………………………………………………………………………………………………..

6. The diagrams below illustrate two types of neurons and associated structures. Study

the diagrams carefully and answer the questions that follow.

(a) (i) Identify the type of neurons illustrated in diagrams N1 and N2. (2 marks)

N1:

…………………………………………………………………………………………………………………………………………

……………………………………………………..………………………………………………………………………………….

N2:

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(ii) Provide two reasons for your identity of the neuron in diagram N1. (2 marks)

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(b) Name each of the structure labeled X and Y in diagram N1. (2 marks)

X: ……………………………………………………………………………………

Y: ……………………………………………………………………………………

(c) Give the general name of the type of cell at position Z in diagram N1. (1 mark)

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(d) Give the general name of the substance in position W in diagram N1 (1 mark)

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Answer question 6 (compulsory) in the spaces provided. Answer either question 7 or 8 in the


6. An investigation was conducted to compare water rate of water loss from twigs of two

different species of plants Q and L. the twigs had equal leaf surfaces. The results of the

investigation were recorded in the below.

Time of the

day

6 a.m 8 a.m 10 a.m 1 p.m 12 p.m 1 p.m 2 p.m 3 p.m 6 p.m 8 p.m 12 a.m

Water loss

gh-h

0 4 20 40 55 36 26 20 2 0 0

Water loss gh

–h Species L

8 20 39 131 198 182 130 81 45 12 12

(a) On the graph paper provided on page 7, plot a graph of Water loss gh-h against time for

the two plants. (7 marks)

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(b) Name the apparatus which might have been used to investigate the rate of water loss.

(1 mark)

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(c) State two precautions that were taken in setting up the experiment. (2 marks)

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Which of the plant species is likely to be adapted to arid conditions? Give a reason.

(2 marks)

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Use the graph to answer the following questions:

(i) At what time of the day was 60gh-1 of water lost by plant species L?

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(ii) What was the rate of water loss from plant species Q at 11.00 am? (1 mark)

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(f) Account for the rate of water loss between 6.00 a.m. to 1.00 p.m. by plant species L.

(4 marks)

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(g) Suggest how the stomata of species Q are structurally adapted to water loss. (2 marks)

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7. Describe how the mammalian male reproductive system is adapted to perform its

functions. (20 marks)

8. Describe the structure and functions of various organelles in a mature animal cell.

(20 marks)

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PROJECTION NO. 64

NAME …………………………………………………………………………………..……… INDEX NO……………..……………..…

SCHOOL …………………………………… CANDIDATE’S SIGNATURE……………………..DATE…………………………………

231/2

BIOLOGY

PAPER 2

(THEORY)

TIME: 2 HOURS



• This paper consist of TWO sections; A and B.

• Answer all the questions in the section A in the spaces provided.





Score

Candidates

Score

A

1 8

2 8

3 8

4 8

5 8

B 6 20

7 20

8 20

Total Score 80

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1. Examine the diagram below and use it to answer the questions that follow.

(a) Name the parts labeled. (3mks)

B __________________________________________________________________________

C __________________________________________________________________________

D __________________________________________________________________________

(b) What is substance which makes up part labeled A? (1mk)

___________________________________________________________________________

____________________________________________________________________________

(c) Name the process by which mineral salts move into structure B. (1mk)

____________________________________________________________________________

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(d) Explain what happens when a red blood cell is put in distilled water. (3mks)

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____________________________________________________________________________

2. The figure below is a pedigree showing the inheritance of colourblindness, a disease transmitted

through a recessive gene located on the X-chromosome.

(b) Using the symbol N for normal gene and n for colourblind gene, write down the genotypes

of parents 1 and 2. (2mks)

____________________________________________________________________________

____________________________________________________________________________

(b) Work out the possible genotypes of the children 3, 4 and 5. (4mks)

1 2

3 4 5 6

7 8 9

Normal male

Colourblind male

Normal female

male Colourblind male

KEY

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(c) The diagrams below illustrate some chromosome mutations.

A

B

C

Identify the mutations. (3mks)

Meiosis

X X

A

B

C

D

E

F

V

U

W

X

E

F

V

U

W

X

A

C

B

D

A

B

C

D

B

C

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A __________________________________________________________________________

B __________________________________________________________________________

C __________________________________________________________________________

3. The diagram below shows structures of the bat wing and human arm.

(c) These structures are thought to have same ancestral origin. State one structural similarity

and one adaptational difference between the two.

(i) Structural similarity. (1mk)

____________________________________________________________________

_____________________________________________________________________

(ii) Adaptational difference. (2mks)

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

Wing membrane

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(b) Give two other examples of structures in nature that show the type of evolution as in

(a) above. (2mks)

____________________________________________________________________________

____________________________________________________________________________

(c) Distinguish between the terms ‘chemical evolution’ and ‘organic evolution’. (2mks)

____________________________________________________________________________

____________________________________________________________________________

____________________________________________________________________________

____________________________________________________________________________

(d) What is the study of fossils called? (1mk)

____________________________________________________________________________

____________________________________________________________________________

___________________________________________________________________________

4. The diagram below represents some hormones, their sources and functions in a mammal.

Master gland

I III V

Stimulates tests Stimulates

growth of follicles Stimulates

in ovary development

of corpus luteum

II

Stimulates

spermatogenesis IV

Stimulates VI

development of Stimulates

secondary sexual development

characteristics of uterine wall

Male

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(a) Identify the gland described as master gland. (1mk)

__________________________________________________________________________

___________________________________________________________________________

(d) Name the hormones:- (4mks)

II __________________________________________________________________________

III _________________________________________________________________________

V __________________________________________________________________________

VI _________________________________________________________________________

(c) Describe the consequences of deficiency of hormone II in man. (2mks)

____________________________________________________________________________

____________________________________________________________________________

___________________________________________________________________________

____________________________________________________________________________

(d) Other than stimulate development of uterine wall, suggest two other functions of hormone

VI. (2mks)

____________________________________________________________________________

____________________________________________________________________________

____________________________________________________________________________

____________________________________________________________________________

5. Ascaris lumbricoides is an endoparasite.

(a) Name the genus to which it belongs. (1mk)

____________________________________________________________________________

____________________________________________________________________________

(b) State the habitat of the organism. (1mk)

____________________________________________________________________________

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(c) State three ways in which the organism is adapted to living in its habitat. (3mks)

____________________________________________________________________________

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____________________________________________________________________________

____________________________________________________________________________

(d) Mention three ways of preventing spread of the parasite. (3mks)

____________________________________________________________________________

____________________________________________________________________________

____________________________________________________________________________

___________________________________________________________________________


Answer question 6 (compulsory) and EITHER question 7 or 8 in the spaces provided after

question 8.

6. The table below shows how the quantities of sweat and urine vary with external temperature.

External temperature C Urine cm³/hr Sweat cm³/hr

0 100 5

5 90 6

10 80 10

15 70 20

20 60 30

25 50 60

30 40 120

35 30 200

(b) On the same graph, plot the quantities of urine and sweat produced against the external temperature. (7mks)

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(b) At what temperature are the amounts of sweat and urine produced equal? (1mk)

__________________________________________________________________________

__________________________________________________________________________

(c) What happens to the amount of sweat produced as the temperature rises? Explain the

observation. (3mks)

__________________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

(d) Explain the observation made on the amount of urine produced as the temperature

increases. (3mks)

__________________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

(e) How is the skin adapted for temperature regulation? (6mks)

__________________________________________________________________________

__________________________________________________________________________

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7. Describe the structural adaptations of the mammalian heart to its function. (20mks)

8. Describe how water moves from the soil to the leaves in a tree. (20mks)

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PROJECTION NO. 65

BIOLOGY

PAPER II

TIME: 2 HOURS

NAME:…………………………………………………………….ADM.NO:……..…………….

CLASS:……………………………………………………………………………………………..

INSTRUCTIONS


80 MARKS

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SECTION A

1. a) What is immunity to a disease (1mk)

……………………………………………………………………………………………………….……………………………………….

………………………………………………………………………………………………………….…………………………………….

b) Distinguish between the following types of immunity

(i) Natural immunity (1mk)

………………………………………………………………………………………………………………………………………………..

………………………………………………………………………………………………………………………………………………..

(ii) Artificial immunity (1mk)

………………………………………………………………………………………………………………………………………………..

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2. The figure below represents a transverse section of a root

i) Name the parts labeled A, B and D (3mks)

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ii) State the role of the part labeled C (1mk)

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3. a) Define the term balanced diet (2mks)

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b) Explain the importance of each of the following during digestion in human beings

(i) Teeth (1mk)

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ii) Saliva (2mks)

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c) State the role of each of the following in photosynthesis (3mks)

(i) Light

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ii) Chlorophyll

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iii) Carbon (IV) oxide

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Further excess

X

Excess corrective mechanism A

Negative feedback

Norm Norm

Negative feedback

Deficiency corrective mechanism B

X

Further deficiency

a) Name the principle labeled X (1mk)

……………………………………………………………………………………………………………………………

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b) If the above diagram represented blood sugar regulation

(i) State the corrective mechanisms carried out at A (2mks)

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ii) The condition that may result from the further excess (1mk)

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iii) the hormone that would be responsible for correcting the deficiency (1mk)

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c) Give the reasons as to why plants have less elaborate excretory systems as compared to

animals (3mks)

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5. a) State two effects of air pollution to plants (2mks)

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b) Name two human activities that cause soil pollution (2mks)

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c) How is plasmodium adapted to cause malaria (2mks)

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d) State two ways of controlling the transmission of typhoid (2mks)

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SECTION B

6. The data below shows results obtained from a plant species which was planted around a

homestead to serve as a hedge. The hedge was divided into part I, II and III. The three parts

were treated as indicated in the table and the results collected after 3 years

Part Treatment Percentage cover

in the 1st 2 metres

from the ground

Average width

in metres

Average height

in metres

I Untrimmed throughout 3% 0.5 5.0

II Trimmed twice annually 55% 0.9 3.5

III Trimmed throughout 85% 1.5 2.5

a) Give three deductions one would draw from the above results (3mks)

………………………………………………………………………………………………………………………………………………

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b) Explain the effects of the following on percentage cover; width of hedge and height of

plants

(i) Lack of hedge trimming (3mks)

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(ii) Frequent hedge trimming (4mks)

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c) Using a germinating bean seedling with a 2cm long radical; describe how you would

investigate the region of growth on the radical (5mks)

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d) Name the kind of growth curve obtained

(i) for arthropods when changes in length of body plotted against time (1mk)

……………………………………………………………………………………………………………………………….……………

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ii) Give reason as to why this kind of curve is obtained for arthropods (2mks)

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iii) Name the hormone that inhibits metamorphosis in insects and where it is produced

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7. a) Explain how the tracheal system in arthropods is adapted for gaseous exchange

(10mks)

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b) Explain the mechanism of opening and closing of the stomata using photosynthetic theory

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PROJECTION NO. 66

NAME……………………………………………INDEX NO……………………………

CANDIDATE’S SIGN………………………….DATE……………………………….

SCHOOL……………………………………………………………………………………….

231/2

BIOLOGY

PAPER 2

THEORY

TIME: 2 HOURS


1) Write your name and index number in the spaces provided above.

2) Sign and write the date of examination in the spaces provided above.

3) This paper consisits of section A and B.

4) Answer ALL questions in section A in the spaces provided above.

5) In section B answer questions 6 (compulsory) and either question 7 or 8 in the spaces


FOR EXAMINERS’ USE ONLY.


A 1 8

2 8

3 8

4 8

5 8

B 6 20

7 20

8 20

TOTAL 80


Candidates should check the question paper to ascertain that all pages are printed as indicated and no

questions are missing.

SECTION A (40MARKS)

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1 The diagram below shows a set up to investigate a factor necessary for germination.

a) Name the factor under investigation. (1mk)

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. b) State the role of pyrogallic acid in the set up. (1mk)

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c) Which type of respiration is taking place in the beans? (1mk)

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d) Write a word equation for the process named in (c) above. (1mk)

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e) Explain why plants can only carry out the above respiration process for a short

while. (1mk)

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f) State other three factors necessary for germination. (3mks)

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2 The diagram below shows the arrangement of bones and muscles in a human arm.

a) Name the parts labeled A , B and C. (3mks)

A……………………………………………………………………………

B……………………………………………………………………………

C……………………………………………………………………………

b) Explain how parts D and E bring about flexing and extending of the arm.

(2mks)

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c) Name the types of joints found at points X and Y. (2mks)

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d) Name a fluid found in all the movable joints. (1mk)

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3 a) i) Name the blood vessel that connects arteries to veins. (1mk)

…………………………………………………………………………………………………..…

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ii) Explain three ways in which the vessels named in (a) (i) above are adapted

to carry their functions. (3mks)

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b) Name the blood vessel with the highest concentration of:

i) Glucose (1mk)

…………………………………………………………………………………………………..…

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ii) Carbon (IV) Oxide. (1mk)

…………………………………………………………………………………………………..…

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c) i) Sate the function of cardiac muscles. (1mk)

…………………………………………………………………………………………………..…

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ii) What is a single circulation? (1mk)

…………………………………………………………………………………………………..…

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4 In a family of four children, the father had blood group A while the mother had blood

group B.One of the children had blood group O.The father wanted to commit suicide

accusing his wife of infidelity?

a) Was this accusation justified? (1mk)

…………………………………………………………………………………………………..…

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b) With the use of a punnet square work out the genotype of other children.

(4mks)

c) The child of blood group O can donate blood , to all other children but can receive

blood from none. Explain. (2mks)

…………………………………………………………………………………………………..…

……………………………………………………………………………………………….

…………………………………………………………………………………………………..…

……………………………………………………………………………………………….

d) One of the other children was able to receive blood from all the other children but

donate to none. What was the blood group of such a child? (1mk)

…………………………………………………………………………………………………..…

……………………………………………………………………………………………….………

5 a) Distinguish between Osmosis and Active transport. (2mks)

…………………………………………………………………………………………………..…

………………………………………………………………………………………………………

……………………………………………………………………………………………………….

b) Study the figure below and answer the questions that follow.

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i) Which solution has higher concentration of free water molecules.

(1mk)

…………………………………………………………………………………………………..…

…………………………………………………………………………………………..………….

ii) Which solution is more concentrated? (1mk)

…………………………………………………………………………………………………..…

………………………………………………………………………………………………………

iii) In which direction will Osmosis take place? (1mk).

…………………………………………………………………………………………………..…

………………………………………………………………………………………………………

iv) What does semi-permeable membrane represents in an animal cell.

(1mk)

…………………………………………………………………………………………………..…

………………………………………………………………………………………………………

c) Name two processes in living organisms that depend on Osmosis. (1mk)

…………………………………………………………………………………………………..…

………………………………………………………………………………………………………

……………………………………………………………………………………………………..

SECTION B (40MARKS)

6 A group of students estimated the population of the grasshoppers in the school compound.

The table below shows the number of grasshoppers collected from the eight sites within

the compound.

Site 1 2 3 4 5 6 7 8

No. of grasshoppers 250 50

190 220 85 300 175 30

a) Draw histograms to represent the number of grasshoppers collected from each site. (6mks)

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b) The students caught 240 grasshoppers marked them and then released them. After

five days they caught 160 grasshoppers and found that 40 were marked. Work out

the grasshoppers population. (3mks)

c) Identify the method used in (b) above. (1mk)

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d) Name the instrument the students used to collect and mark the grasshoppers.

(2mks)

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e) The students encountered a number of limitations. State any three of the

limitations. (3mks)

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f) The students observed the organisms and placed them into their correct phylum

and class. (2mks)

i) Name; Phylum…………………………………………………………..

Class…………………………………………………………….

ii) What features were observed for the grasshoppers to be placed in their

correct; (3mks)

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Phylum………………………………………………………………….

Class…………………………………………………………………….

7 Describe how the human skin is adapted to its function. (20mks)

8 a) State three aspects of light that are important in photosynthesis. (3mks)

b) Describe how the leaves of plants are adapted to carry out photosynthesis.

(17mks)

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PROJECTION NO. 67

Name……………………………………………………..… Index No:………………………….

231/2 Candidate’s Signature ……………………………

BIOLOGY Date: ……………………………..…………..…

PAPER 2

(THEORY)

TIME: 2 HOURS

231/2

Biology

Paper 2

2 ½ Hours


Write your name and index number in the spaces provided above

Sign and write the date of examination in the spaces provided.

This paper consists of sections A and B answer all questions in section A

In section B answer question 6compulsory and either question 7or 8 in spaces provided after

question 8


For Examiners Use Only

This paper consists of 11printed pages. Candidates should check to ascertain that all pages are

printed as indicated and that no questions are missing.

Section Question Maximum score Candidate’s score

A 1 2 3 4 5

9 8 7 8 8

B 6 7 8

20 20 20

TOTAL 80

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1. The diagram below represents a part of thoracic region of a human being;

(a) Name the structures labeled K and L (2mks)

K………………………………………………

L……………………………………………….

(b) How is structure R bring about inhalation (4mks)

………………………………………………………………………………………………

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(c) Give the scientific name of the organism that causes whooping cough (1mk)

……………………………………………………………………………………………

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(d) Name a vertebra that articulates with the ribs to the back of the chest region? (1mk)

………………………………………………………………………………………………

……………………………………………………………………………………….……...

2. The diagram below shows the vertical section of a female reproductive system

Ribs

L

K

R

Vulva

B

Rectum

Ureter

A Funnel of oviduct

Urethra

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(a) Name the parts labeled A and B (2mks)

A…………………………………………..…………………..

B………………………………………………………………

(b) Name the gonadotrophic hormone that affects the part labeled A (1mk)

……………………………………………………………………………………………

(c) (i) State a hormone(s) produced by each of the following structures in a female

(2mks)

Ovary

……………………………………………………………………………………………………

Placenta

……………………………………………………………………………………………………..

(ii) State one effect of each of the above hormones on uterine wall (2mks)

………………………………………………………………………………………………

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(d)Name a sub-division in the kingdom plantae that exhibit double fertilization (1mk)

………………………………………………………………………………………………

……………………………….……......................................................................................

3. (a) Define the following terms as used in animal nutrition

(i)Dentition (1mk)

………………………………………………………………………………………………

… ………………………………………………………………………………………….…...

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(ii) Homodont and heterodont teeth (2mks)

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(b) State two functions of ileum (2mks)

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(c) Explain the importance of the following in the process of photosynthesis; (2mks)

(i) Chlorophyll

………………………………………………………………………………………………

… ………………………………………………………………………………………….…...

(ii) Light

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… ………………………………………………………………………………………...…...

(d) State one use of Potassium in (K+) ion the body (1mk)

………………………………………………………………………………………………

……...

4. A man who suffers from Haemophilia which is a sex linked gene; marries a woman who is

normal for the condition. However, one of their daughters Jane turns to be haemophiliac.

Taking ‘H’ for normal trait and ‘h’ for haemophilia

(a) State the genotypes of the parents (2mks)

………………………………………………………………………………………………

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(b) (i) Work out the genotypes of the offspring show your work (4mks)

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(ii) State the genotype of Jane (1mk)

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(c) What is polyploidy (1mk)

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… ……………………………………………….......................................................................

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5. The diagram below represents a longitudinal section through the human eye

(a) Name the parts labeled K and L (2mks)

K……………………………………………………………….

L………………………………………………………….

(b) A person in totally dark room switches on light. Describe the changes that will occur to

structure N (3mks)

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(c) How does the human eye obtain nutrients? (3mks)

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Eye

Fovea centralis

L

K N

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SECTION B (40 MKS)

Answer question 6 (Compulsory) and either question 7 or 8 in the spaces provide after

question 8

6. The glucose level in mg/100cm3 of blood was determined in two persons Y and Z. Both

had stayed for 6 hours without taking food. They were on equal amount of glucose at the

start of the experiment. The amount of glucose in their blood was determined at intervals.

The results are as shown in the table below:

Time (Mins) Glucose level in Y Blood in mg/100cm3

0

20

30

45

60

80

100

120

140

85

105

116

130

100

93

90

90

88

78

110

130

170

195

190

140

130

120

(a) On the same graph and on the same axis, plot a graph of glucose level in blood against

time (7mks)

(b) What was the concentration of glucose in blood of person Y and Z at 50th minute?

(2mks)

Person Y

………………………………………………………………………………………………

…………………………………………………………………………..………….……...

Person Z

………………………………………………………………………………………………

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(c) Account for the level of glucose for a person Y

(i) During the first 45 minutes (2mks)

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… ………………………………………………………………………………………….…...

(ii) After 45th minute to the end (4mks)

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(d) Discuss the effect of higher glucose level in blood above 90mg/100cm3 (3mks)

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(e) State two advantages of homoitherms over paikilotherms (2mks)

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7.(a) A dicotyledonous stem offer support to the plant. Give three necessities for this support

. (3mks)

(b) Describe the adaptation of the stem of a dicotyledonous plant to its function (17mks)

8. (a) Describe the dentition of carnivorous mammals and their adaptation to the mode of

Feeding (10mks)

(b) Explain the different forms of chromosomal mutation (10mks)

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PROJECTION NO. 68

NAME ………………………………………… INDEX NO …….…………………….………..

SCHOOL ………………………………………… SIGNATURE …………..……....………………..

DATE ……………….…………………..

231/2

BIOLOGY

PAPER 2

(THEORY)

2 HOURS

Kenya Certificate of Secondary Education (K.C.S.E)

231/2

BIOLOGY

PAPER 2

(THEORY)

2 HOURS




• Answer ALL questions in section A in the spaces provided. In section B answer question 6 (compulsory)

and either question 7 or 8 in the spaces provided after question 8

• This paper consists of 11 Printed pages. Candidates should check the question paper to ensure that all the

papers are printed as indicated and no questions are missing



A 1 8

2 8

3 8

4 8

5 8

B 6 20

7 20

8 20

Total score 80

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1. a) What is diffusion (2marks)

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b) How do the following factors affect the rate of diffusion?

i.Diffusion gradient (1mark)

............................................................................................................................. .........................

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ii.Surface area volume ratio (1mark)

.............................................................................................................................................. ........

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............................................................................................................................. .........................

iii.Temperatures (1mark)

.......................................................................................................................................................

.......................................................................................................................................................

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c) Outline three roles of active transport in human body? (3marks)

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.

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2. a) Give the differences between the following structures in wind and insect pollinated

flowers? (3marks)

i. Anther

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ii. Pollen grains

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iii. Stigma

............................................................................................................................. .........................

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b) What is the importance of pollination (1mark)

.......................................................................................................................................................

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c) Explain how a seed is formed after an ovule is fertilized (4marks)

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3. A cross between a red flowered plant and white flowered plant produces plants with pink

flowers .Using letter R to represent the gene for red colour and W for white colour,

a) What were the parental genotypes? (1mark)

.......................................................................................................................................................

.......................................................................................................................................................

......................................................................................................................................................

b) Work out a cross between F1 plants. (4marks)

.......................................................................................................................................................

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c)

i. Give the phenotypic ratio of F2 plants

............................................................................................................................. .........................

......................................................................................................................................................

ii. Genotypic ratio of F2 plants

(1mark)

.......................................................................................................................................................

.......................................................................................................................................... .............

d) Name a characteristic in humans which is controlled by multiple alleles

(1mark)

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4. The diagram below shows a vertical section through a mammalian heart.

a) Name the parts labeled A, B, E, and F (4marks)

A............................................................................................................................ .

B............................................................................................................................ .

E............................................................................................................................ ..

F............................................................................................................................ ..

b) Use arrows to show the direction in which blood flows in the heart (2marks)

c) Give a reason why the wall of chamber C is thicker than chamber D (2marks)

.......................................................................................................................................................

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5.

a) What is the difference between Darwinian and Lamarckian theories of evolution (2marks)

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b) What is meant by the following terms. Give an example in each case.

i. Homologous structures (1mark)

............................................................................................................................. .........................

......................................................................................................................................................

Example

............................................................................................................................. .........................

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ii. Analogous structures (1mark)

............................................................................................................................. .........................

................................................................................................................................................... ...

Example

..................................................................................................................... .................................

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iii. Vestigial structures (1mark)

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Example

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SECTION B

Answer question 6(compulsory) in the spaces provided and either question 7 or 8 in the

spaces provided after 8.

6. During germination and growth of a cereal, the dry weight of endosperm, the embryo and

the total dry weight were determined at two day intervals. The results are shown in the table

below:

Time after planting (days)

Dry weight of endosperm (mg)

Dry weight of embryo (mg)

Total dry weight (mg)

0 43 2 45

2 40 2 42

4 33 7 40

6 20 17 37

8 10 25 35

10 6 33 39

a) Using the same axes, draw graphs of dry weight of endosperm, embryo and the total dry

weight against time. (7marks)

b) What was the total dry weight on day 5 (1mark)

.......................................................................................................................................................

.......................................................................................................................................................

c) Account for

i. Decrease in dry weight of endosperm from 0 to 10 (2marks)

............................................................................................................................. .........................

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............................................................................................................................. .........................

ii. Increase in dry weight of embryo from day 0 to day 10 (2marks)

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iii. Decrease in total dry weight from day 0 to day 8 (1mark)

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............................................................................................................................. .........................

iv. Increase in total dry weight after day 8 (1mark)

................................................................................................................................ ......................

............................................................................................................. .........................................

............................................................................................................................. .........................

d) State two factors within the seed and two outside the seed that cause dormancy

i. Within the seed. (2marks)

............................................................................................................................. .........................

......................................................................................................................................................

............................................................................................................................. .........................

......................................................................................................................................................

ii. Outside the seed (2marks)

......................................................................................................................................................

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.....................................................................................................................................................

e) Give two characteristics of meristematic cells (2marks)

.......................................................................................................................................................

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......................................................................................................................................................

7. Describe how the human kidney functions (20marks)

8. Explain how abiotic factors affect plants. (20marks)

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PROJECTION NO. 69

NAME …………………………………………… INDEX NO …….…………………..

SCHOOL ………………………………………… SIGNATURE …………..……....…….

DATE ……………….………..

231/2

BIOLOGY

PAPER 2

(THEORY)

2 HOURS




• Answer ALL questions in section A in the spaces provided. In section B answer

question 6 (compulsory) and either question 7 or 8 in the spaces provided after

question 8.

• This paper consists of 10 Printed pages. Candidates should check the question

paper to ensure that all the papers are printed as indicated and no questions

are missing



A 1 8

2 8

3 8

4 8

5 8

B 6 20

7 20

8 20

Total score 80

of 744


SECTION A. 40 MARKS

Answer all the Questions in this section.

1. a) What is meant by the following ecological terms.

i) Population. (1mark)

……………………………………………………………………………………………………………………………

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ii) Community. (1 mark)

……………………………………………………………………………………………………………………………

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iii) Ecosystem (1mark)

……………………………………………………………………………………………………………………………

…………………………………..………………………………………………………………………………………

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b) What is the importance of the following in an ecosystem?

i) Decomposers (1 mark)

……………………………………………………………………………………………………………………………

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ii) Predation. (1mark)

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c) Give a reason why two species in an ecosystem cannot occupy the same niche.

(2marks)

……………………………………………………………………………………………………………………………

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…………………………………………………………………………………………………………………………..

d) Name the bacteria found in the root nodules of leguminous plant. (1mark)

……………………………………………………………………………………………………………………………

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…………………………………………………………………………………………………………………………..

2. The apparatus whose diagram is given below can be used to demonstrate

results of a physiological process that occurs in a mammal. To use the

apparatus, the experimenter places his mouth at the point marked X and

breathes in and out gently

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a) State the observations in the boiling tube when the experimenter

i) Breathes in

Boiling tube A (2 marks)

……………………………………………………………………………………………….…………………………

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Boiling tube B (1mark)

……………………………………………………………………………………………….…………………………

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………………………………………………………………………………………………………………………..

ii) Breathes out?

Boiling tube A

(1mark)

……………………………………………………………………………………………………………………………

…………………..……………………..………………………………………………………….……………………

Boiling tube B

(1 mark)

……………………………………………………………………………………………………………………………

……………..…………………………..………………………………………………………….……………………

b) What conclusion can you draw from the results of this experiment ( 2 marks)

……………………………………………………………………………………………………………………………

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c) What is the purpose of the boiling tube A? (1mark)

……………………………………………………………………………………………………………………………

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3. The diagram below shows how the iris and pupil of human eye appear under

different conditions.

a) Name the structures labeled X and Y ( 2 marks)

X

………………………………………………………………………………………………………….

Y

…………………………………………………………………………………………………………

b) i) State the condition that lead to the change in appearance shown in the

diagram labeled B. ( 1mark)

……………………………………………………………………………………………………………………………

………………………………………………………………..……………………………………………….………..

ii) Describe the changes that lead to the appearance of the iris and pupil as

shown in the diagram labeled B.(4 marks)

……………………………………………………………………………………………………………………………

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iii) What is the significance of the changes described in (b) (ii) above. ( 1 mark)

……………………………………………………………………………………………………………………………

…………………..……………………..…………………………………………………………………………….…

X

Y

Radial muscles

A B

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4.

a) Name cells A,B and C stating their functions. ( 6 marks)

Cell Name Function

A

B

C

b) Name the organelle D and F (2marks)

D

……………………………………………………………………………………………………………………………

…………………..……………………..…………………………………………………………….…………………

F

……………………………………………………………………………………………………………………………

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5. In a plant breeding experiment, tall plants were crossed with dwarf plants. They

produced 93 tall plants and 94 dwarf plants.

a) State the phenotypic ratio (1 mark)

……………………………………………………………………………………………………………………………

…………………..……………………..………………………………………………………………………

……………………………………………………………………………………………………………………………

…………………..……………………..………………………………………………………………………

b) What were the genotypes of the offspring? Show your working. ( 4marks)

……………………………………………………………………………………………………………………………

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……………………………………………………………………………………………………………………………

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c) What is a test cross? . ( 1mark)

……………………………………………………………………………………………………………………………

…………………..……………………..………………………………………………………………………………

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d) What is a natural selection (2marks)

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Answer question 6 (compulsory) and either 7 or 8

6. In an experiment to determine the effect of ringing on the concentration of

sugar in the phloem, a ring of bark from the stem of a tree was cut and

removed. The amount of sugar in grammes per 16cm3 piece of bark above the

ring was measured over a 24 – hour period. Sugar was also measured in the

bark of a similar stem of tree of same species which was not ringed. The results

are shown in the table below.

Time of the day Amount of sugar in grammes per 16 cm 3 piece of bark

Normal stem Ringed stem

6.45 A.M 0.78 0.78

9.45 A.M 0.80 0.91

12.45 P.M 1.81 1.01

3.45 P.M 1.80 1.04

6.45 P.M 1.77 1.00

9.45 P.M 0.73 0.95

12.45 A.M 0.65 0.88

a) Using the same axis, plot graphs of the amount of sugar against time for

both stems (6 marks)

b) At what time was the amount of sugar highest in the.

i) Ringed stem. (1mark)

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ii) Normal stem. (1 mark)

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c) How much sugar would be in the ringed stem if it was measured at 3: 45 am.

( 1mark)

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d) Give a reason why there was sugar in the stem of both trees at 6:45am.

( 2marks)

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e) Account for the shape of the graph for the tree with the ringed stem between:

(3 marks)

i) 6:45 and 3:45 am.

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ii) 3:45 pm and 12:45 am. (2 marks)

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f) Name the structures in the phloem that are involved in the translocation of

sugars. (2 marks)

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7. (a) Explain the conditions necessary for germination in seeds. (12 marks)

(b) Describe the role of the following hormones in growth and development of

plants.

i) Auxins (4 marks)

ii) Gibberellins ( 4 marks)

8. a) what is meant by the following terms

i) excretion

ii) secretion

iii) Egestion

iv) homeostasis

(b) Explain how the osmotic pressure in the human blood is maintained at

normal level. (12 marks)

(c) Describe how the oxygen in the alveolus reaches the red cells. (4 marks)

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PROJECTION NO. 70

NAME ………………………………………… INDEX NO …….…………………..

SCHOOL ………………………………………… SIGNATURE …………..……....…….

DATE ……………….………..

231/2

BIOLOGY

PAPER 2

(THEORY)

2 HOURS




• Answer ALL questions in section A in the spaces provided. In section B answer question 6

(compulsory) and either question 7 or 8 in the spaces provided after question 8

• This paper consists of 8 Printed pages. Candidates should check the question paper to ensure

that all the papers are printed as indicated and no questions are missing



A 1 8

2 8

3 8

4 8

5 8

B 6 20

7 20

8 20

Total score 80

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Section A (40 marks)

Answer all the questions

1. The equation below represents a metabolic process that occurs in a certain

organ in the mammalian body.

Ammonia + carbon (IV) oxide enzyme organic compound Q + water

(a) Name the process represented in the equation above. (1 mark)

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(b) Name the organ in which the process occurs. (1mark)

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(c) Why is the process important to mammals (1mark)

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(d) Identify the organic compound Q. (1 mark)

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(e) Explain the source of ammonia in the organ named in (b) above. (2 marks)

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(f) What happens to organic compound Q.? (2 marks)

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2. An athlete training to take part in an international competition moved to a high

altitude area where he was to train for twelve (12) days before the

competition. He took his pulse rate per minute daily and tabulated them as

shown below

DAY 1 2 3 4 5 6 7 8 9 10 11 12

Pulse per

minute

72 78 89 92 92 90 86 80 77 74 72 72

(a) Other than pulse rate, name one other process which was affected by change

in altitude. (1mark)

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(b) Account for the change in pulse rate from.

(i) Day 1 to day 7 (1 mark)

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(ii) Day 8 to day 12

(1 mark)

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(c) Explain the advantage this athlete has over the one who trains in a lower

altitude area. (2 marks)

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(d) The equation below represents a reaction which takes place during rapid

muscular movements in humans.

Glucose lactic acid + 150kj

(i) State two effects of this reaction to an individual (2 marks)

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(ii) How is lactic acid finally eliminated from the muscle tissue after the muscle

return to normal movement (1 mark)

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3. Study the diagram below and answer the questions which follow.

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(i) Identify the muscle represented by letters A and B (2 marks)

A

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B

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(ii) Describe how muscles A and B cause straightening of joint C (2 marks)

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(b) Name the joint C (1 mark)

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(c) Name parts label D, E and F (3marks)

D

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E

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F

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4. In a certain bird species red flight feathers is controlled by gene R while white

flight feather is controlled by gene r. The heterozygous condition Rr results into

pink flight feathers.

(a) By use of a punnet or fussion lines, find the genotype of a cross between

pink flight feathered bird and white flight feathered bird.

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(b) Which type of dominance is illustrated here? (1 mark)

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(c) i) Identify the nuclei acid whose base sequence is shown below. (1 mark)

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G - A - C - U - A - G - C - G - U

(ii) Give a reason for your answer in (i) above (1 mark)

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(iii) If this nucleic acid was involved in protein synthesis, how many amino

acid would be present in the protein synthesized.

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5. The diagram below represents a longitudinal section through the ileum wall.

a) Identify the structures labeled X and Y (2 marks)

X

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Y

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b) State one function of X and Y (2 marks)

X

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Y

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c) State two functions of the ileum (2 marks)

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d) Explain the role of the liver in digestion (1mark)

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e) State the endocrine (hormonal) role of pancreas in a mammal (1mark)

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SECTION B

Answer question 6 compulsory and either question 7 or 8 in the space

provided

6. The diagram below shows an experiment that was carried out to measure rate

of photosynthesis in a water plant when exposed to different light intensities.

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The shoot was exposed to different light intensities and the rate of

photosynthesis estimated by counting the

number of bubbles of the gas leaving the shoot per minute. The results are

tabulated below.

Number of bubble per

minute

7 14 20 24 26 27 27 27

Light intensity (arbitrary

units)

1 2 3 4 5 6 7 8

a) Draw the graph of the number of bubbles produced per minute against light

intensity. (6 marks)

b) At what light intensity did the shoot produce

i) 18 bubbles per minute (1mark)

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ii) 25 bubbles per minute (1mark)

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c) Give two better ways of measuring the rate of photosynthesis other than

counting bubbles produced per minute. (2 marks)

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d) What is role of light intensity in photosynthesis (2marks)

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e) Account for the expected results if the experiment was done at the following

temperatures.

(i) 40c (2 marks)

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(ii) 340 ( 2marks)

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(iii) 600 ( 2marks)

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f) Apart from light intensity and temperature, name other two factors that affect

the rate of photosynthesis. (2marks)

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7. (a) How are lungs adapted to their function?

(c) Describe the mechanism of opening and closing of the stomata using

the photosynthesis theory.

8. (a) Describe the various mechanism of fruit and seed dispersal.

(b) Describe the various events that occur in a flower after fertilization.

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BIOLOGY PP2 EXAMINERS' PROJECTION 70 PAPERS.(new ...

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