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AP Biology
AP Biology Lab ReviewFred and Theresa HoltzclawWebb School of Knoxville
Using Figures from The LabBench by Theresa Knapp Holtzclaw
Modified from work by Kim Foglia
AP Biology
Lab 1: Diffusion & OsmosisFactors that affect diffusion across the membrane
AP Biology
Lab 1: Diffusion & Osmosis Description
dialysis tubing filled with starch-glucose solution in beaker filled with IKI solution
dialysis bags in different molarities
potato cores in sucrose solutions
AP Biology
Lab 1: Diffusion & Osmosis Concepts
semi-permeable membrane diffusion osmosis solutions
hypotonic hypertonic isotonic
water potential
AP Biology
Lab 1: Diffusion & Osmosis Conclusions
water moves from high concentration of water (hypotonic=low solute) to low concentration of water (hypertonic=high solute)
solute concentration & size of molecule affect movement through semi-permeable membrane
AP Biology
Water potential and water movementKnow how water potential is measured and relationship to solute concentration and pressure potential
water moves from a region of high water potential to a region of low water potential
What are the 2 components of water potential?
AP Biology
Calculating Water PotentialWater potential is calculated using the following
formula:
Water potential ( ) = pressure potential ( ) + solute potential( )
Pure water at atmospheric pressure has a solute potential of zero.
As solute is added, the value for solute potential becomes more ________ and water potential _____.
AP Biology
Know the relationship of molarity to osmotic concentration
AP Biology
1. In beaker B, what is the water potential of the distilled water in the beaker, and of the beet core?
a. Water potential in the beaker = 0, water potential in the beet core = 0b. Water potential in the beaker = 0, water potential in the beet core = -0.2c. Water potential in the beaker = 0, water potential in the beet core = 0.2d. Water potential in the beaker cannot be calculated, water potential in the beet core = 0.2e. Water potential in the beaker cannot be calculated, water potential in the beet core = -0.2
AP Biology
2. Which of the following statements is true for the diagrams?
a.The beet core in beaker A is at equilibrium with the surrounding water.
b.The beet core in beaker B will lose water to the surrounding environment.
c.The beet core in beaker B would be more turgid than the beet core in beaker A.
d.The beet core in beaker A is likely to gain so much water that its cells will rupture.
e.The cells in beet core B are likely to undergo plasmolysis.
AP Biology
Lab 1: Diffusion & OsmosisESSAY 1992A 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. a description of how you would set up and perform the experiment;b. the results you would expect from your experiment; andc. an explanation of those results based on the principles involved.
Be sure to clearly state the principles addressed in your discussion.
AP Biology
Lab 2: Enzyme CatalysisWhat factors affect the rate of an enzyme reaction?
Description measured factors affecting enzyme
activity H2O2 H2O + O2
measured rate of O2 production
catalase
Name an enzyme, substrate, products
AP Biology
AP Biology
Lab 2: Enzyme CatalysisHow can the structure of an enzyme be altered? Concepts
substrate enzyme
enzyme structure product denaturation of protein experimental design
rate of reactivity reaction with enzyme vs. reaction without
enzyme optimum pH or temperature
test at various pH or temperature values
AP Biology
Lab 2: Enzyme CatalysisBe able to calculate the rate of a reax
AP Biology
Lab 2: Enzyme Catalysis Conclusions
enzyme reaction rate is affected by: pH temperature substrate concentration enzyme concentration
calculate rate?
AP Biology
1. In order to keep the rate of reaction constant over the entire time course, which of the following should be done?
a. Add more enzyme
b. Gradually increase the temperature after 60 seconds
c. Add More substrate
d. Add H2SO4 after 60 seconds.
e. Remove the accumulating product
Lab 2: Enzyme Catalysis
AP Biology
2. What is the role of sulfuric acid (H2SO4) in this experiment?
a.It is the substrate on which catalase acts.
b.It binds with the remaining hydrogen peroxide during titration.
c.It accelerates the reaction between enzyme and substrate
d.It blocks the active site of the enzyme.
e.It denatures the enzyme by altering the active site.
Lab 2: Enzyme Catalysis
AP Biology
3. A student was performing a titration for this laboratory, and accidentally exceeded the endpoint. What would be the best step to obtain good data for this point?
a.Estimate the amount of KMnO4 that was in excess, and subtract this from the result.
b.Repeat the titration using the reserved remaining sample.
c.Obtain data for this point from another lab group.
d.Prepare a graph of the data without this point, and then read the estimated value from the graph.
Lab 2: Enzyme Catalysis
AP Biology
ESSAY 2000The effects of pH and temperature were studied for an enzyme-catalyzed reaction. The following results were obtained.
a. How do (1) temperature and (2) pH affect the activity of this enzyme? In your answer, include a discussion of the relationship between the structure and the function of this enzyme, as well as a discussion of ho structure and function of enzymes are affected by temperature and pH.
b. Describe a controlled experiment that could have produced the data shown for either temperature or pH. Be sure to state the hypothesis that was tested here.
Lab 2: Enzyme Catalysis
AP Biology
Lab 3: Mitosis Description
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
AP Biology
Lab 3: Mitosis Concepts
mitosis interphase prophase metaphase anaphase telophase
Conclusions Mitosis
cell division growth, repair making clones
longest phase = interphase each subsequent phase is
shorter in duration
I P M A T
AP Biology
The cell cycle
Know these:
MitosisCytokinesisCell Cycle1 hour
5-6 hours 10-12 hours
4-5 hours
AP Biology
Cytokinesis in animal cells
Compare and contrast plant and animal cytokinesis
AP Biology
Lab 3: Mitosis Know the events of mitosis and meiosis in plant and animal cells
AP Biology
Lab 3: Mitosis
AP Biology
Lab 3: Mitosis
AP Biology
AP Biology
Lab 3: Mitosis
AP Biology
Lab 3: Mitosis
AP Biology
Mitosis in a plant cell
Lab 3: Mitosis
AP Biology
Mitosis in an onion root
Know how to calculate the relative duration of each stage
AP Biology
The cell cycle in a certain cell type has a duration of 10 hours. The nuclei of 660 cells showed 33 cells in anaphase. What is the approximate duration of anaphase in these cells?
a.2 minutesb.10 minutesc.20 minutesd.30 minutese.600 minutes
Lab 3: Mitosis
AP Biology
Lab 3: Meiosis Stages Importance of Crossing Over
farther genes are from each other, the greater number of crossovers
AP Biology
Lab 3: Mitosis & Meiosis meiosis
meiosis 1 meiosis 2
crossing over Synapsis tetrads in prophase 1
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Meiosis I
******Note that at the end of Meiosis I homologs have separated
AP Biology
Meiosis II
Now, what is separated in Meiosis II?
AP Biology
Meiosis
1. How many times is the DNA replicated?2. How many divisions?3. When is chromosome # reduced?
AP Biology
INDEPENDENT ASSORTMENT INTRODUCES VARIABILITY
AP Biology
CROSSING OVER INTRODUCES VARIABILITY
AP Biology
Points of Variability1. Independent assortment
How many different combinations of male/female chromosomes are possible in humans?
2. Crossing over
3. Random fertilization
and all of this variation is without mutation . . .
AP Biology
AP Biology
Lab 3: Meiosis in Sordaria Meiosis
4:4 arrangement in ascospores
no crossover any other arrangement
crossover 2:2:2:2 or 2:4:2
AP Biology
Sordaria analysis
% crossovertotal crossover
total offspring=
distance fromcentromere
% crossover
2=
AP Biology
Sordaria analysis
AP Biology
A group of asci formed from crossing light-spored Sordaria with dark-spored produced the following results:
Number of Asci Counted Spore Arrangement7 4 light/4 dark spores8 4 dark/4 light spores3 2 light/2 dark/2 light/2 dark spores4 2 dark/2 light/2 dark/2 light spores1 2 dark/4 light/2 dark spores2 2 light/4 dark/2 light spores
How many of these asci contain a spore arrangement that resulted from crossing over?
a.3 b.7 c.8 d.10 e.15
AP Biology
Lab 3: Mitosis & MeiosisESSAY 1987Discuss the process of cell division in animals. Include a description of mitosis and cytokinesis, and of the other phases of the cell cycle. Do not include meiosis.
ESSAY 2004Meiosis reduces chromosome number and rearranges genetic information.a. Explain how the reduction and rearrangement are accomplished in
meiosis.b. Several human disorders occur as a result of defects in the meiotic
process. Identify ONE such chromosomal abnormality; what effects does it have on the phenotype of people with the disorder? Describe how this abnormality could result from a defect in meiosis.
c. Production of offspring by parthenogenesis or cloning bypasses the typical meiotic process. Describe either parthenogenesis or cloning and compare the genomes of the offspring with those of the parents.
AP Biology
http://apcentral.collegeboard.com/apc/members/repository/ap04_sg_biology_37082.pdf
Link to rubric
AP Biology
Lab 4: Photosynthesis
AP Biology
Lab 4: Photosynthesis Description
determine rate of photosynthesis under different conditions light vs. dark boiled vs. unboiled chloroplasts chloroplasts vs. no chloroplasts
use DPIP in place of NADP+
DPIPox = blue DPIPred = clear
measure light transmittance paper chromatography to
separate plant pigments
AP Biology
Lab 4: Photosynthesis Concepts
photosynthesis Photosystem 1
NADPH chlorophylls & other
plant pigments chlorophyll a chlorophyll b xanthophylls carotenoids
experimental design control vs. experimental
AP Biology
Lab 4: Photosynthesis Conclusions
Pigments pigments move at different rates based on
solubility in solvent Photosynthesis
light & unboiled chloroplasts produced highest rate of photosynthesis
Which would be the control? DPIP + no chloroplasts
AP Biology
What is the Rf for chlorophyll a?
Lab 4: Photosynthesis
AP Biology
1. Which graph would be the most likely result of performing the photosynthesis experiment using fresh chloroplasts placed in light and DPIP?
2. What is the best explanation for graph B? a.The DPIP was too pale at the beginning of the experiment.b.The chloroplast solution was too concentrated.c.The experimenter used chloroplasts that were damaged and could not respond to light.d.The blank was not properly used to calibrate the spectrophotometer.
Lab 4: Photosynthesis
AP Biology
3. What effect would adding more DPIP to each experimental tube have on these results? a.Each curve would be shifted downward but would keep the same general shape.b.The curve in graph C would rise more steeply and level off sooner.c.The curve in graph A would have the same general shape as the curve in graph C.d.The chloroplasts would absorb more light energy, so there would be no change.
Lab 4: Photosynthesis
AP Biology
4. What is the role of DPIP in this experiment? a.It mimics the action of chlorophyll by absorbing light energy.b.It serves as an electron donor and blocks the formation of NADPH.c.It is an electron acceptor and is reduced by electrons from chlorophyll.d.It is bleached in the presence of light, and can be used to measure light levels.
Lab 4: Photosynthesis
AP Biology
5. Some students were not able to get many data points in this experiment because the solution went from blue to colorless in only 5 minutes for the unboiled chloroplasts exposed to light. What modification to the experiment do you think would be most likely to provide better results?
a.Increase the number of drops of chloroplasts used from 3 to 5.
b.Double the volume of DPIP so that the solution has a lower initial transmittance.
c.Modify the blank so that the initial transmittance is higher.
d.Use fresher spinach and prepare the chloroplast solution during the laboratory procedure.
e.Change the wavelength at which data is collected
Lab 4: Photosynthesis
AP Biology
Lab 4: PhotosynthesisESSAY 2004 (part 1)A controlled experiment was conducted to analyze the effects of darkness and boiling on the photosynthetic rate of incubated chloroplast suspensions. The dye reduction technique was used. Each chloroplast suspension was mixed with DPIP, an electron acceptor that changes from blue to clear when it is reduced. Each sample was placed individually in a spectrophotometer and the percent transmittance was recorded. The three samples used were prepared as follows.
Sample 1 — chloroplast suspension + DPIPSample 2 — chloroplast suspension surrounded by foil wrap to provide a
dark environment + DPIPSample 3 — chloroplast suspension that has been boiled + DPIP
Data are given in the table on the next page.
a. Construct and label a graph showing the results for the three samples.b. Identify and explain the control or controls for this experiment.c. The differences in the curves of the graphed data indicate that there were
differences in the number of electrons produced in the three samples during the experiment. Discuss how electrons are generated in photosynthesis and why the three samples gave different transmittance results.
AP Biology
Lab 4: PhotosynthesisESSAY 2004 (part 2)
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
