AP Biology

AP Biology

AP Biology Lab Review

AP Biology

Lab 1: Diffusion & Osmosis

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Procedure u Part A - Dialysis tubing filled with starch-glucose

solution in beaker filled with IKI solution u Part B - Effect of sucrose concentration on osmosis


Part A Part B

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Lab 1: Diffusion & Osmosis Potato cores in sucrose solutions

Part C

Using the graph, determine the molar concentration of the potato cylinders. This is equivalent to the sucrose molarity in which the potato core mass is constant.

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D. Water Potential Calculation

Osmotic potential can be calculated using the following formula:

ψπ = –iCRT

i = ionization constant (1 for sucrose)

C = osmotic molar concentration (determined in part C)

R = pressure constant (R = .0831 liter bars/mole °Kelvin)

T = temperature (°Kelvin)

Water Potential (ψ) = Pressure Potential (ψp) + Osmotic Potential (ψπ)

Water potential is determined by calculating the osmotic potential when the pressure potential is zero.

Osmotic potential can be calculated using the following formula: ψπ = –iCRT

i = ionization constant (1 for sucrose) C = osmotic molar concentration (moles/liter) (determined in part C)

R = pressure constant (R = .0831 liter bars/mole °Kelvin) T = temperature (°Kelvin)

Part C

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Plasmolysis Turgor pressure

Distilled water: Salt water: Part E

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Concepts u Semi-permeable membrane u Diffusion u Osmosis u Solutions

§ Hypotonic § Hypertonic §  Isotonic

u Water potential


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Conclusions u Water moves from high water potential

(hypotonic=low solute) to low water potential (hypertonic=high solute)

u Solute concentration & size of molecule affect movement through semi-permeable membrane


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Procedure u Measured factors affecting enzyme activity u H2O2 ⎯⎯⎯→ H2O + O2

u Measured rate of hydrogen peroxide decomposition by enzyme catalysis

catalase

Lab 2: Enzyme Catalysis

Titrate with KMnO4

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Concepts u Substrate u Enzyme

§  enzyme structure u Product u Denaturation of protein u Experimental design

§  rate of reactivity w  reaction with enzyme vs. reaction without enzyme

§  optimum pH or temperature §  titration


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Conclusions u Enzyme reaction rate is affected by:

§  pH §  temperature §  substrate concentration §  enzyme concentration


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Lab 3: Mitosis & Meiosis

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Procedure u Cell stages of mitosis

§  exam slide of onion root tip §  count number of cells in each stage to determine

relative time spent in each stage u Stages of & crossing over in meiosis

§ model cell stages & crossing over §  farther gene is from centromere the greater number of crossovers §  observed crossing over in fungus, Sordaria fimicola

w arrangement of ascospores


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Concepts u  Cell Cycle

§  interphase §  prophase §  metaphase §  anaphase §  telophase

u  Meiosis §  meiosis I

w  separate homologous pairs §  meiosis II

w  separate sister chromatids

u  Crossing over §  in prophase I

I P M A T


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Lab 3: Mitosis & Meiosis Conclusions

u Mitosis §  cell division

w growth, repair w Reproduction in unicellular organisms

§  longest phase = prophase §  each subsequent phase is shorter in duration

u Meiosis §  reduction division

w making gametes w  increasing variation

§  crossing over in Prophase 1

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Sordaria fimicola Analysis

% crossover total crossover

total offspring =

distance from centromere

% crossover

2 =

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Lab 4: Photosynthesis

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Lab 4: Photosynthesis Procedure

u  Paper chromatography to separate plant pigments u  Calculate Rf values

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Procedure u  Determine rate of photosynthesis under different conditions

§  light vs. dark §  boiled vs. unboiled chloroplasts §  chloroplasts vs. no chloroplasts

u  Use DPIP in place of NADP+ §  DPIPox = blue §  DPIPred = clear

u  Measure light transmittance using spectrophotometer


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Concepts u Photosynthesis u Photosystems

§ NADPH u Chlorophylls & other

plant pigments §  chlorophyll a §  chlorophyll b §  xanthophylls §  carotenoids

u Experimental design §  control vs. experimental


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Conclusions u Pigments

§  pigments move at different rates based on solubility in solvent and affinity to chromatography paper

u Photosynthesis §  light & unboiled

chloroplasts produced highest rate of photosynthesis

Which is the control? Cuvette #2 = DPIP + chloroplasts + light


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Time (min)

Light, Unboiled % transmittance

Sample 1

Dark, Unboiled % transmittance

Sample 2

Light, Boiled % transmittance

Sample 3

0 28.8 29.2 28.8

5 48.7 30.1 29.2

10 57.8 31.2 29.4

15 62.5 32.4 28.7

20 66.7 31.8 28.5


Explain the above sample data ...

Table 1: Rate of Photosynthesis

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Lab 4: Photosynthesis Graph 1:

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Lab 5: Cell Respiration

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Procedure u Using respirometer to measure rate of O2

consumption by pea seeds §  non-germinating peas §  germinating peas §  effect of temperature §  control for changes in pressure & temperature in

room


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Room temperature Ice bath

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Concepts u Cell respiration u Experimental design

§ Control vs. experimental §  Function of KOH §  Function of vial with only glass beads

Lab 5: Cell Respiration What is

corrected difference?

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Conclusions u ↓temp = ↓cell respiration u ↑germination = ↑cell respiration

Calculate rate?


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Lab 6: Molecular Biology

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Description u Bacterial Transformation

§  insert foreign gene in bacteria by using engineered plasmid §  also insert ampicillin resistant gene on same plasmid as selectable marker

u Gel Electrophoresis §  cut DNA with restriction enzyme §  fragments separate on gel based

on size


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Concepts u Transformation u Plasmid u Selectable marker

§  ampicillin resistance u Restriction enzyme u Gel electrophoresis

§ DNA is negatively charged

§  smaller fragments travel faster


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Lab 6: Bacterial Transformation Conclusions

u Can insert foreign DNA using a vector (plasmid)

u Ampicillin becomes selecting agent for transformed bacteria.

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Lab 6: Gel Electrophoresis

Electrophoresis chamber

Power source

To which end must the DNA (wells) be placed? + or - ?

Why do we need to use a buffer solution?

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Conclusions

DNA = negatively charged

Smaller fragments travel faster & therefore farther

Correlate distance to size

Lab 6: Gel Electrophoresis

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Lab 7: Mendelian Genetics

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Description u Given fly of unknown genotype use crosses

to determine mode of inheritance of trait


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Concepts u Phenotype vs. genotype u Dominant vs. recessive u P, F1, F2 generations u Sex-linked u Monohybrid cross u Dihybrid cross u Test cross u Chi square


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Conclusions: Can you solve these?

Case 1

Case 2


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Lab 8: Population Genetics

Random vs. Non-random mating

Size of population & Gene pool

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Description u Simulations were used to study effects of

different parameters on frequency of alleles in a population §  Selection

§ Heterozygous advantage

§ Genetic drift


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Concepts u  Hardy-Weinberg equilibrium

§  p + q = 1 §  p2 + 2pq + q2 = 1 §  Required conditions

w  large population w  random mating w  no mutations w  no natural selection w  no migration

u  Gene pool u  Heterozygous advantage u  Genetic drift

§  Founder effect §  Bottleneck


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Conclusions u Recessive alleles remain hidden

in the pool of heterozygotes § Even lethal recessive alleles are not completely

removed from population u Know how to solve H-W problems!

§ To calculate allele frequencies, use p + q = 1 § To calculate genotype frequencies or how many

individuals, use, p2 + 2pq + q2 = 1


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Lab 9: Transpiration

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Protocol u Test the effects of environmental factors on

rate of transpiration §  temperature §  humidity §  air flow (wind) §  light intensity


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Concepts u Transpiration u Stomates u Guard cells u Xylem

§ Adhesion § Cohesion

w H bonding


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Conclusions u ↑Transpiration

§  ↑ wind §  ↑ light

u ↓Transpiration §  ↑ humidity


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Lab 10: Circulatory Physiology

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Description u Study factors that affect heart rate

§ Body position § Level of activity

u Determine whether an organism is an endotherm or an ectotherm by measuring change in pulse rate as temperature changes

§ Daphnia


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Concepts § Thermoregulation § Endotherm § Ectotherm § Q10

u  Measures increase in metabolic activity resulting from increase in body temperature

u  Daphnia can adjust their temperature to the environment, as temperature in environment increases, their body temperature also increases which increases their heart rate

u  For many biological reactions, the Q10 is around 2!


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Conclusions u  Activity increase heart rate

§  in a fit individual pulse & blood pressure are lower & will return more quickly to resting condition after exercise than in a less fit individual

u  Pulse rate changes in an ectotherm as external temperature changes


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Lab 11: Animal Behavior

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Description u Set up an experiment to study behavior in an

organism § Betta fish agonistic behavior § Drosophila mating behavior §  Pillbug kinesis


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Concepts u  Innate vs. learned behavior u Experimental design

§ Control vs. experimental § Hypothesis

u Choice chamber § Temperature § Humidity § Light intensity §  Salinity § Other factors


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Hypothesis development u Poor:

I think pillbugs will move toward the wet side of a choice chamber.

u Better: If pillbugs prefer a moist environment, then when they are randomly placed on both sides of a wet/dry choice chamber and allowed to move about freely for 10 minutes, most will be found on the wet side.


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Experimental design Sample size


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Lab 12: Dissolved Oxygen Dissolved O2 availability

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Lab 12: Dissolved Oxygen

Winkler Method O2 Probe

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Description u  Measure primary productivity by measuring O2

production u  Factors that affect amount of dissolved O2

§  Temperature w  as ↑water temperature, its ability to hold O2 decreases

§  Photosynthetic activity w  in bright light, aquatic plants produce more O2

§  Decomposition activity w  as organic matter decays, microbial respiration consumes O2

§  Mixing & turbulence w wave action, waterfalls & rapids aerate H2O & ↑O2

§  Salinity w  as water becomes more salty, its ability to hold O2 decreases


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Concepts u  Dissolved O2 u  Primary productivity

§  measured in 3 ways: w  amount of CO2 used w  rate of sugar (biomass) formation w  rate of O2 production

u  Net productivity vs. Gross productivity u  Cell respiration


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Conclusions u ↑temperature = ↓dissolved O2

u ↑light = ↑photosynthesis = ↑O2 production u O2 loss from cell respiration u ↑cell respiration = ↓dissolved O2

(consumption of O2)


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Lab 12: Dissolved Oxygen Nomograph: To measure how much oxygen water can hold (saturation), you need to be able to read a nomograph.

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