AP Biology Lab Review

Big Idea 1: Evolution

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

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)

Sample Histogram of a Population

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

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

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

Lab 2: Mathematical Modeling: Hardy-Weinberg

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

Lab 2: Mathematical Modeling: Hardy-Weinberg Sample Results

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

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

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?

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

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

Lab 3: Comparing DNA Sequences using BLAST  Evolutionary Relationships

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

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

Lab 3: Comparing DNA Sequences using BLAST  Evolutionary Relationships

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

Lab 3: Comparing DNA Sequences using BLAST  Evolutionary Relationships

Big Idea 2: cellular processes: energy and communication

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

Lab 4: Diffusion & Osmosis

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)

Lab 4: Diffusion & Osmosis

Potato Cores in Different Concentrations of Sucrose

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

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.

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)

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

Plant Pigments & Chromatography

Floating Disk Technique

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

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

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

Lab 6: Cellular Respiration

Lab 6: Cellular Respiration

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

Lab 6: Cellular Respiration

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

Any Questions??