1. AP EXAM REVIEW SESSION III Be prepared, not scared! 
Experimental Design
12 AP Labs

2. EXPERIMENTAL DESIGN
Clearly state a hypothesis using the “If…,then” format.
Set up a control group and indicate its purpose.
Use a large sample size.
Identify the independent & dependent variables.
Indicate which variables you will hold constant.
Indicate how you will manipulate the variable you will test; in other words, how will you conduct your experiment?
Describe how the function you are testing is affected by the change in the variable; in other words, how is the dependent variable changing in response to the independent variable?
Describe how you will measure the change in the variable titration, measuring temp every 2 minutes, etc
Describe how you will verify your experiment (repeat the experiment many times).
Describe how you will analyze your data (run a Chi square test, graph the data)
Relate possible results to the hypothesis; in other words, what results support or reject your hypothesis?

3. The AP Labs . . . A Walk Down Memory Lane 

4. AP Lab 1 – Diffusion & Osmosis
Cell Transport
Tonicity
Movement of water determined by water potential
Ψ = Ψ S + Ψ P

5. AP Lab 1 – Diffusion & Osmosis, cont
Part A
Diffusion across a semipermeable membrane
Set-up = glucose + starch in dialysis tubing; iodine in beaker
Part B
Determined % change in mass of known molarities of sucrose solutions (dH2O, 0.2 M → 1.0M) placed in distilled water
Increase or decrease in mass of bags following incubation?

6. AP Lab 1 – Diffusion & Osmosis, cont
Part C
Set up potato cubes in different molarities of sucrose, then calculated, graphed % change in mass
Some gained mass, some lost mass
Molarity of potato = ??
Part D
Plasmolysis

7. AP Lab 2 – Enzyme Catalysis

8. AP Lab 2 – Enzyme Catalysis, cont
Purpose: To develop a better understanding of enzyme function by working with the enzyme catalase
Reaction:
KMnO4 used for titration – deep purple color. If H2O2 is present, it reacts with KMnO4 to form clear product – provides way to measure H2O2
Procedure
Determined actual concentration of H2O2 in 1.5% solution of H2O2
Determined the 24-hour uncatalyzed reaction rate by performing a titration on the hydrogen peroxide left sitting overnight without the addition of catalase.
Catalase was allowed to react with H2O2 for varying amounts of time. H2SO4 was added to stop the reaction, then amount of H2O2 remaining was titrated using KMnO4. Data was graphed and reaction rate was calculated to determine the effect of time on reaction rate.

9. AP Lab 3 – Mitosis & Meiosis
Purpose: To observe stages of cell cycle in apical meristem tissue of root tip.

10. AP Lab 3 – Mitosis & Meiosis, cont

11. AP Lab 3 – Mitosis & Meiosis, cont
To observe crossing over in asci of Sordaria by looking at the pattern & colors of ascospores

12. AP Lab 4 – Plant Pigments & Photosynthesis

13. AP Lab 4 – Plant Pigments & Photosynthesis
Part A
Purpose: To separate plant pigments using chromatography
Different plant pigments vary in their affinity for the chromatography paper and their solubility in the solvent, therefore will travel different distances along chromatography paper

14. AP Lab 4 – Plant Pigments & Photosynthesis

15. AP Lab 4 – Plant Pigments & Photosynthesis

16. AP Lab 4 – Plant Pigments & Photosynthesis
Part B
Purpose: To measure the rate of photosynthesis in (1) an unboiled chloroplast solution kept in the dark, (2) an unboiled chloroplast solution exposed to light, and (3) a solution containing boiled chloroplasts exposed to light.
A dye reduction technique was used.
DPIP acts as electron acceptor. It is normally a blue color but becomes colorless when it is reduced.
Color change measured as % transmittance by spectrophotometer or % absorbance by colorimeter.
Provides a means to measure electron excitation

17. AP Lab 5 – Cell Respiration
Purpose: To determine the effect of factors on the rate of cellular respiration by measuring oxygen consumption/carbon dioxide production by yeast

18. AP Lab 5 – Cell Respiration

19. AP Lab 5 – Cell Respiration

20. AP Lab 6 – Molecular Genetics
Part A – Transformation
First, two suspensions of bacteria in log phase of growth were made competent by heat shock and treatment with CaCl2
One tube exposed to plasmid containing gene for ampicillin resistance, one tube not exposed to plasmid
Each tube is plated on 2 agar plates, one with ampicillin, one without, incubated, then checked for growth
Expected results?

21. AP Lab 6 – Molecular Genetics
Part B – Restriction Enzyme Cleavage
Identical DNA samples cut with 2 different restriction enzymes
HindIII fragments measured, base pairs per fragment provided, data graphed
EcoRI bands measured, then graph used to interpolate number of base pairs per fragment

22. AP Lab 7 – Genetics of Organisms
Determined phenotypes of P x P
by looking at representative flies
Analysis of F1 provided information
about cross
Predictions made for F2
Null hypothesis:
F2 offspring counted; results evaluated using Chi square
Chi-square
“Goodness of Fit” Test
Degrees of freedom =
If the calculated Chi square value is greater than or equal to the p value listed for 0.05, null hypothesis is rejected. This means you are 95% certain that the data does not fit the expected value.

23. AP Lab 8 – Population Genetics & Evolution
Purpose: To become familiar with the Hardy-Weinberg equation and to use H-W to calculate the number of alleles in a population
Five criteria for H-W equilibrium
Having a widow’s peak is dominant to lacking a widow’s peak. In a population of 920 people, 510 show the dominant phenotype. How many individuals would you expect of each of the three possible genotypes for this trait?

24. AP Lab 9 – Transpiration Part A Transpiration =
Measured transpiration rate in plants exposed to light, fan, darkness, and ambient conditions

25. AP Lab 9 – Transpiration Part B
Cross section of dicot stem structure prepared by using a microtome to slice thin sections, staining them, fixing them to a slide, and examining the slide under the microscope

26. AP Lab 10 – Physiology of the Circulatory System
Purpose
To become familiar with taking blood pressure readings,
To determine the effect of exercise on pulse rate, and to determine fitness by comparing pulse rate when standing, reclining, after exercising, and calculating the amount of time required for pulse rate to return to normal after exercise.
To determine the effect of temperature on heart rate is determined using a test organism.

27. AP Lab 11 – Animal Behavior
Purpose: To observe animal behavior and to design an experiment testing the response of an organism to a stimulus.
Taxis vs kinesis

28. AP Lab 12 – Dissolved Oxygen & Aquatic Primary Productivity
Part A
Purpose: To determine the relationship between dissolved O2 concentration and temperature

29. AP Lab 12 – Dissolved Oxygen & Aquatic Primary Productivity
Part B
Primary productivity = rate of photosynthesis
Net productivity = (Primary productivity) – (Respiration)
Set up bottles with varying amounts of light to calculate effect of light on net productivity
Measured O2 concentration using Winkler method
[dO2 ] fixed
Iodine concentration measured by titrating with sodium thiosulfate, starch indicator