1. AP Biology
Lab Review

2. Big Idea 1: Evolution

3. Lab 1: Artificial Selection
Concepts:
Natural selection = differential reproduction in a population
Populations change over time  evolution
Natural Selection vs. Artificial Selection

4. Lab 1: Artificial Selection
Description:
Use Wisconsin Fast Plants to perform artificial selection
Identify traits and variations in traits
Cross-pollinate (top 10%) for selected trait
Collect data for 2 generations (P and F1)

5. Sample Histogram of a Population

6. Lab 1: Artificial Selection
Analysis & Results:
Calculate mean, median, standard deviation, range
Are the 2 populations before and after selection (P and F1) actually different?
Are the 2 sub-populations of F1 (hairy vs. non-hairy) different?
Are the means statistically different?
A T-test could be used to determine if 2 sets of data are statistically different from each other

7. Lab 2: Mathematical Modeling: Hardy-Weinberg
Concepts:
Evolution = change in frequency of alleles in a population from generation to generation
Hardy-Weinberg Equilibrium
Allele Frequencies (p + q = 1)
Genotypic Frequencies (p2+2pq+q2 = 1)
Conditions:
large population
random mating
no mutations
no natural selection
no migration

8. Lab 2: Mathematical Modeling: Hardy-Weinberg
Description:
Generate mathematical models and computer simulations to see how a hypothetical gene pool changes from one generation to the next
Use Microsoft Excel spreadsheet
p = frequency of A allele
q = frequency of B allele

9. Lab 2: Mathematical Modeling: Hardy-Weinberg

10. Lab 2: Mathematical Modeling: Hardy-Weinberg
Setting up Excel spreadsheet

11. Lab 2: Mathematical Modeling: Hardy-Weinberg
Sample Results

12. Lab 2: Mathematical Modeling: Hardy-Weinberg
Analysis & Results:
Null model: in the absence of random events that affect populations, allele frequencies (p,q) should be the same from generation to generation (H-W equilibrium)
Analyze genetic drift and the effect of selection on a given population
Manipulate parameters in model:
Population size, selection (fitness), mutation, migration, genetic drift

13. Lab 2: Mathematical Modeling: Hardy-Weinberg
Real-life applications:
Cystic fibrosis, polydactyly
Heterozygote advantage (Sickle-Cell Anemia)

14. Lab 2: Mathematical Modeling: Hardy-Weinberg
ESSAY 1989
Do the following with reference to the Hardy-Weinberg model.
a. Indicate the conditions under which allele frequencies (p and q) remain constant from one generation to the next.
b. Calculate, showing all work, the frequencies of the alleles and frequencies of the genotypes in a population of 100,000 rabbits of which 25,000 are white and 75,000 are agouti. (In rabbits the white color is due to a recessive allele, w, and agouti is due to a dominant allele, W.)
c. If the homozygous dominant condition were to become lethal, what would happen to the allelic and genotypic frequencies in the rabbit population after two generations?

15. Lab 3: Comparing DNA Sequences using BLAST  Evolutionary Relationships
Concepts:
Bioinformatics: combines statistics, math modeling, computer science to analyze biological data
Genomes can be compared to detect genetic similarities and differences
BLAST = Basic Local Alignment Search Tool
Input gene sequence of interest
Search genomic libraries for identical or similar sequences

16. Lab 3: Comparing DNA Sequences using BLAST  Evolutionary Relationships
Description:
Use BLAST to compare several genes
Use information to construct a cladogram (phylogenetic tree)
Cladogram = visualization of evolutionary relatedness of species

17. Lab 3: Comparing DNA Sequences using BLAST  Evolutionary Relationships

18. Use this data to construct a cladogram of the major plant groups
Lab 3: Comparing DNA Sequences using BLAST  Evolutionary Relationships
Use this data to construct a cladogram of the major plant groups

19. Lab 3: Comparing DNA Sequences using BLAST  Evolutionary Relationships
Fossil specimen in China
DNA was extracted from preserved tissue
Sequences from 4 genes were analyzed using BLAST

20. Lab 3: Comparing DNA Sequences using BLAST  Evolutionary Relationships

21. Lab 3: Comparing DNA Sequences using BLAST  Evolutionary Relationships
Analysis & Results:
BLAST results: the higher the score, the closer the alignment
The more similar the genes, the more recent their common ancestor  located closer on the cladogram

22. Lab 3: Comparing DNA Sequences using BLAST  Evolutionary Relationships

24. Big Idea 2: cellular processes: energy and communication

25. Lab 4: Diffusion & Osmosis
Concepts:
Selectively permeable membrane
Diffusion (high  low concentration)
Osmosis (aquaporins)
Water potential ()
 = pressure potential (P) + solute potential (S)
Solutions:
Hypertonic
hypotonic
isotonic

26. Lab 4: Diffusion & Osmosis

27. Lab 4: Diffusion & Osmosis
Description:
Surface area and cell size vs. rate of diffusion
Cell modeling: dialysis tubing + various solutions (distilled water, sucrose, salt, glucose, protein)
Identify concentrations of sucrose solution and solute concentration of potato cores
Observe osmosis in onion cells (effect of salt water)

28. Lab 4: Diffusion & Osmosis

29. Potato Cores in Different Concentrations of Sucrose

30. Lab 4: Diffusion & Osmosis
Conclusions
Water moves from high water potential ( ) (hypotonic=low solute) to low water potential () (hypertonic=high solute)
Solute concentration & size of molecule affect movement across selectively permeable membrane

33. Lab 4: Diffusion & Osmosis
ESSAY 1992
A laboratory assistant prepared solutions of 0.8 M, 0.6 M, 0.4 M, and 0.2 M sucrose, but forgot to label them. After realizing the error, the assistant randomly labeled the flasks containing these four unknown solutions as flask A, flask B, flask C, and flask D.
Design an experiment, based on the principles of diffusion and osmosis, that the assistant could use to determine which of the flasks contains each of the four unknown solutions.
Include in your answer:
a description of how you would set up and perform the experiment;
the results you would expect from your experiment; and
an explanation of those results based on the principles involved.
Be sure to clearly state the principles addressed in your discussion.

34. Lab 5: Photosynthesis Concepts: Photosynthesis
6H2O + 6CO2 + Light  C6H12O6 + 6O2
Ways to measure the rate of photosynthesis:
Production of oxygen (O2)
Consumption of carbon dioxide (CO2)

35. Lab 5: Photosynthesis Description:
Paper chromatography to identify pigments
Floating disk technique
Leaf disks float in water
Gases can be drawn from out from leaf using syringe  leaf sinks
Photosynthesis  O2 produced  bubbles form on leaf  leaf disk rises
Measure rate of photosynthesis by O2 production
Factors tested: types of plants, light intensity, colors of leaves, pH of solutions

36. Plant Pigments & Chromatography

37. Floating Disk Technique

39. Lab 5: Photosynthesis Concepts: photosynthesis Photosystems II, I
H2O split, ATP, NADPH
chlorophylls & other plant pigments
chlorophyll a
chlorophyll b
xanthophylls
carotenoids
experimental design
control vs. experimental

42. Lab 6: Cellular Respiration
Concepts:
Respiration
Measure rate of respiration by:
O2 consumption
CO2 production

43. Lab 6: Cellular Respiration
Description:
Use respirometer
Measure rate of respiration (O2 consumption) in various seeds
Factors tested:
Non-germinating seeds
Germinating seeds
Effect of temperature
Surface area of seeds
Types of seeds
Plants vs. animals

45. Lab 6: Cellular Respiration

46. Lab 6: Cellular Respiration

47. Lab 6: Cellular Respiration
Conclusions:
temp = respiration
germination = respiration
Animal respiration > plant respiration
 surface area =  respiration
Calculate Rate

48. Lab 6: Cellular Respiration

52. Lab 6: Cellular Respiration
ESSAY 1990
The results below are measurements of cumulative oxygen consumption by germinating and dry seeds. Gas volume measurements were corrected for changes in temperature and pressure.
a. Plot the results for the germinating seeds at 22°C and 10°C.
b. Calculate the rate of oxygen consumption for the germinating seeds at 22°C, using the time interval between 10 and 20 minutes.
c. Account for the differences in oxygen consumption observed between:
1. germinating seeds at 22°C and at 10°C
2. germinating seeds and dry seeds.
d. Describe the essential features of an experimental apparatus that could be used to measure oxygen consumption by a small organism. Explain why each of these features is necessary.
Cumulative Oxygen Consumed (mL)
Time (minutes) 10 20 30 40
Germinating seeds 22°C
0.0
8.8
16.0
23.7
32.0
Dry Seeds (non-germinating) 22°C
0.2
0.1
Germinating Seeds 10°C
2.9
6.2
9.4
12.5
Dry Seeds (non-germinating) 10°C

53. Any Questions??