Ms Ramirez

AP Biology Page

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The 12 "Must - Do" AP Lab Activities

 

Laboratory activities are an integral component of any college level Biology course.  These activities allow students to process data, formulate hypotheses, and apply what they have learned from a lecture or reading assignment.  The College Board has developed 12 exercises that are both hands-on and high-level, to provide students with an opportunity to gain experiences offered at the college level.

Through out the year we will conduct a selection of these, as well as other labs to prepare you for the AP Exam in May.   These labs require that you analyze and interpret both qualitative and quantitative data, as well as use proper procedures and techniques in order to be successful.   Successful completion of these exercises will prepare you for the Free-Response portion of the AP exam.

Below is a description of each of the 12 laboratory exercises, the expected outcomes for each exercise, expected results at the completion of each lab, sample multiple choice questions related to the exercise, and links to sites with additional information about the topic being studied.

Lab Bench Review of Labs.  Worth a Look!


Select a Lab from the list Below

Laboratory 1: Diffusion and Osmosis

Laboratory 2: Enzyme Catalysis

Laboratory 3: Mitosis and Meiosis

Laboratory 4: Plant Pigments and Photosynthesis

Laboratory 5: Cell Respiration

Laboratory 6: Molecular Biology

Laboratory 7: Genetics Of Drosophila

Laboratory 8: Population Genetics and Evolution

Laboratory 9: Transpiration

Laboratory 10: Physiology of the Circulatory System

Laboratory 11: Behavior: Habitat Selection

Laboratory 12: Dissolved Oxygen and Aquatic Primary Productivity

Ms Ramirez

AP Biology Page

BHS


Laboratory 1: Diffusion and Osmosis

Overview 

In this lab you will investigate the movement of water across semi-permeable membranes. You will also examine the effect of solute concentrations on water potential as it relates to living plant tissues.

Lab #1 Class Data 2004

Objectives

Results

When a solution such as that inside a potato cell is separated from pure water by a selectively permeable membrane water will move by osmosis from the surrounding area where the water potential is higher into the cell where water potential is lower due to the presence of solute. The movement of water into the cell, causes the cell to swell and the cell membrane pushes against the cell wall to produce an increase in pressure (turgor). This process will continue until the water potential of the cell equals the water potential of the pure water outside the cell. At this point, a dynamic equilibrium is reached and net water movement will cease.

Sample Multiple - Choice Questions

Laboratory 2: Enzyme Catalysis

Overview

In this lab you will measure the rate of a reaction in the presence and absence of a catalyst. The catalyst, (catalase), is an enzyme in cells that catalyzes the breakdown of toxic H202.

Lab 2. Enzyme Catalysis Data (2003-2005)
10s 30s 60s 90s 120s 180s 360s Baseline
.364 .340 .449 .574 .694 .699 1.06 3.471
Lab 2. Enzyme Catalysis Data [Sample]
10s 30s 60s 90s 120s 180s 360s
.9 1.8 2.4 2.8 3.1 3.3 3.4

Objectives

Results

In the first few minutes of an enzymatic reaction, the number of substrate molecules is usually so large compared to the number of enzyme molecules that changing the substrate concentration does not (for a short period at least) affect the number of successful collisions between substrate and enzyme. During this early period, the enzyme is acting on substrate molecules at a constant rate. The slope of the graph line during this early period is called the initial velocity of the reaction. The initial velocity, or rate, of any enzyme catalyzed reaction is determined by the characteristics of the enzyme molecule. It is always the same for an enzyme and its substrate as long as temperature and pH are constant and substrate is present in excess. Also, in this experiment the disappearance of the substrate, H202 is essential in this reaction. Once all the H202 has reacted, any more KMnO4 added will be in excess an will not be decomposed.

Sample Multiple - Choice Questions

  1. Which of the following is LEAST likely to increase the forward rate of an enzyme-mediated reaction?
    1. An increase in the substrate concentration
    2. An increase in the enzyme concentration
    3. An increase in the product concentration
    4. An increase in pH
    5. An increase in the temperature

Laboratory 3: Mitosis and Meiosis

Sordaria Octad Preparations

Overview

In this lab you will study plant mitosis using prepared slides of onion root tips and will calculate the relative period of the phases of mitosis in the meristem of root tissue. You will also study the crossing over and recombination that occurs during meiosis.

Objectives

Results

The relative length of mitotic stages are, 53.4% of prophase, 17.4% of metaphase, 16.8% of anaphase and 12.4% of telophase. Meiosis is important for sexual reproduction because it reduces the chromosome number by half and it also results in new combinations of genes through independent assortment and crossing over, followed by the random fertilization of eggs by sperm.

Laboratory 4: Plant Pigments and Photosynthesis

Overview

In this lab you will separate plant pigments using paper chromatography. You will also measure the rate of photosynthesis in isolated chloroplasts using a measurement technique that involves the reduction of the dye, DPIP. The transfer of electrons during the light-dependent reactions of photosynthesis reduces DPIP and changes its color from blue to colorless.

Objectives

Results

The solvent moves up the paper by capillary action, which occurs as a result of the attraction of solvent molecules to the paper and the attraction of solvent molecules to one another. As the solvent moves up the paper, it carries along any substances dissolved in it, in this case pigments. The pigments are carried along at different rates because they are not equally soluble in the solvent and because they are attracted, to different degrees, to the cellulose in the paper through the formation of hydrogen bonds. Also, as the DPIP is reduced and becomes colorless, the resultant increase in light transmittance is measured over a time course using a spectrophotometer.

Sample Multiple - Choice Questions


Laboratory 5: Cell Respiration

O2 Graph and CO2 Graph

Overview

In this lab you will measure oxygen consumption during respiration as a change in gas volume in germinating and nongerminating peas at two different temperatures.

Objectives

 Results

Germinating peas respire and need to consume oxygen in order to continue the growing process. Pea seeds are nongerminating and do not respire actively. These seeds are no longer the site of growth and thus do not need oxygen for growth. In consideration to temperature, at higher temperatures more oxygen is consumed which means more respiration is occurring. 686 kilocalories are released during respiration. When temperature decreases molecular motion slows down and respiration decreases because less energy is made available.

Laboratory 6: Molecular Biology

Overview

In this lab you will investigate some basic principles of genetic engineering. Plasmids containing specific fragments of foreign DNA will be used to transform E. coli cells, conferring antibiotic (ampicillin) resistance and the Lac + phenotype (ability to metabolize lactose). Restriction enzyme digests of phage lambda DNA will also be used to demonstrate techniques for separating and identifying DNA fragments using gel electrophoresis.

Objectives

Results

Bacterial Transformation-Ampicillin resistance: In this exercise, we will introduce competent E. Coli cells to take up the plasmid pAMP which contains a gene for ampicllin resistance. Normally, E. Coli cells are destroyed by the antibiotic ampicillin, but E. Coli cells that have been transformed will be able to grow on agar plates containing ampicillin. Thus, we can select for transformants; those cells that are not transformed will be killed by ampicillin; those that have been transformed will survive.

Restriction Enzyme Cleavage of DNA: Restriction endonuclease recognizes specific DNA sequences in double-stranded DNA and digests the DNA at these sites. The result is the production of fragments of DNA of various lengths corresponding to the distance between identical DNA sequences within the chromosome. By taking DNA fragments and systematically reinserting the fragments into an organism with minimal genetic material, it is possible to determine the function of particular gene sequences

Electrophoresis: fragments of DNA can be separated by gel electrophoresis when any molecule enters the electrical field, the mobility or speed at which it will move is influenced by the charge (negative charges travel to positive/top pole of gel), the density of the molecule, (the smaller the molecule, the faster it travels), the strength of the electrical field, and the density of the medium (gel) which it is migrating.

Sample Multiple - Choice Questions

  1. After growth on ampicillin to select bacteria transformed with a mixture of recombinant DNA containing plasmids, you must identify a clone containing a specific gene sequence. You would:
  1. Blot transfer clones to membranes, and screen using a radioactive probe complementary to the gene.
  2. Re-grow bacteria in ampicillin where only transformants containing the gene of interest can grow.
  3. Culture bacteria in both ampicillin and tetracycline to select for bacteria containing the gene of interest.
  4. Digest DNA from the plasmid to isolate the gene fragment.
  5. Do a restriction map of plasmid DNA to identify the correct clone

Laboratory 7: Genetics Of Drosophila

Overview

In this lab you will use the fruit fly Drosophila melanogaster to do genetic crosses. You will learn how to collect and manipulate fruit flies, collect data from F1 and F2 generations, and analyze the results from a monohybrid, dihybrid or sex link cross.

Objectives

Results

From this lab, you will be able to find genotypes and phenotypic expression within a fruit fly. Also, recessive genes and mutations will be revealed as the student crosses a variety of Drosophila alleles. For example, if a female carrier for an x-linked, recessive trait, was crossed with a male without the recessive trait the results would be:

  1. A population consists of 20 individuals of which 64% are homozygous dominant for a particular trait and the remaining individuals are all heterozygous. All of the following can explain the situation except
  1. Genetic drift is occurring
  2. The recessive allele is deleterious
  3. All homozygous recessive individuals emigrate
  4. The population is very small
  5. Only heterozygous individuals mate

Laboratory 8: Population Genetics and Evolution

Hardy-Weinberg Data (2002-2006)

Overview

In this lab you will learn about Hardy-Weinberg law of genetic equilibrium and study the relationship between evolution and changes in allele frequency by using your class as a sample population.

Objectives

Results

Assuming that Hardy-Weinberg equilibrium is maintained allele and genotype frequencies should remain constant from generation to generation. For this to happen the five following situations must all occur:

    1. Population is very large. The effects of chance on changes in allele frequencies is thereby greatly reduced.

3.There is no mutation of alleles.

4. No differential migration occurs, (no immigration or emigration).

In humans, several genetic diseases have been well characterized. Some of these diseases are controlled by a single allele where the homozygous recessive genotype has a high probability of not reaching reproductive maturity. If this were to occur both the homozygous dominant and heterozygous individuals will survive while the homozygous recessive will become extinct.

Sample Multiple - Choice Questions

  1. Which of the following generates the formation of adaptations?
  1. Genetic drift
  2. Mutations
  3. Gene flow
  4. Sexual reproduction
  5. Natural selection
  1. All of the following are examples of evolution, except:
  1. Mutations in an individual
  2. Changes in an allele frequency in a population
  3. Changes in an allele frequency in a species
  4. Divergence of a species into two species
  5. Adaptive Radiation

 

Laboratory 9: Transpiration

Overview

In this lab you will apply what you learned about water potential from Lab 1 (Diffusion and Osmosis) to the movement of water within the plant. You will study the organization of the plant stem as it relates to these processes by observing sections of fresh tissue.

Objectives

Results

Conditions that cause a decreased rate of water loss from leaves result in a decreased water potential gradient from stem to leaf and therefore in a decreased rate of water movement up the stem to the leaves. Conditions that cause an increased rate of water loss from leaves result in an increase in the water potential gradient from stem to leaf and therefore in an increase in the rate of water movement up the stem to the leaves.

    1. Room Conditions
    1. Floodlight
    1. Fan
    1. Mist

Adaptations to reduce leaf water loss include a reduced number of stomates, an increase in the thickness of the leaf cuticle, a decrease in leaf surface area, and adaptations that decrease air movements around stomates, such as dense hairs and sunken stomates. Because leaves are all different in size, reporting the water loss without considering a unit area would provide non-comparable data.

Sample Multiple - Choice Questions

  1. Which of the following series of terms correctly indicates the gradient of water potential from lowest water potential to highest water potential?
    1. Air, leaf, stem, root, soil
    2. Soil, root, stem, leaf, air
    3. Root, leaf, stem, air, soil
    4. Air, soil, root, leaf, stem
    5. Stem, leaf, root, soil, air

Laboratory 10: Physiology of the Circulatory System

Overview

You will learn how to measure blood pressure and measure pulse rate under different physiological conditions: standing, reclining, after the baroreceptor reflex, and during and immediately after exercise. The blood pressure and pulse rate will be analyzed and related to a relative fitness index. You will also measure the effect of temperature on the heart rate of the Daphnia magna, and calculate a Q10 for the relationship between temperature and heart rate.

Objectives

Results

The sphygmomanometer measures the blood pressure. The blood pressure cuff is inflated so that blood flow stops to through the brachial artery in the upper arm. A stethoscope is used to listen to blood flow entering the brachial artery. When blood first enters the artery, snapping sounds called the sounds of Korotkoff are generated.

    1. Blood pressure and heart rate increase when you move from a reclining to a standing position counteracting gravitational pull on the blood
    2. Elevated arterial blood pressure indicates increased arterial resistance to blood flow
    3. Fit individuals can pump a larger volume of blood with each contraction and deliver more oxygen to muscle tissue than the hearts of unfit individuals. As a result, blood pressure and heart rate increases are smaller for fit individuals, and the time required to return to normal conditions is shorter for fit individuals than unfit individuals.
    4. For the Daphnia, remember that ectothermic animals use behavior to regulate their body temperatures and that Q10 cannot be determined for endothermic animals because body temperatures remain constant regardless of environmental temperatures.

Sample Multiple - Choice Questions

  1. A Q10 value of 3 in an ectothermic animal means that the metabolic rate
    1. Triples when body temperature triples
    2. Triples when body temperature increases by 10° C
    3. Doubles when the body temperature increases by 3° C
    4. Doubles when the body temperature increases by 10° C
    5. Triples when the body temperature decreases by 10° C

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Laboratory 11: Behavior: Habitat Selection

Overview

In this lab, you will examine the habitat preferences of the brine shrimp, Artemia. You will use controlled experimentation to determine the thermal, pH, and light environments selected by Artemia. Based on your experience with this lab, you will design an experiment that could be used to survey other variables and other organisms.

Objectives

Results

When conducting this experiment, a couple of things should be understood.

    1. Artemia are able to survive in a wide range of salty environments by they tend to live in really salty environments.
    2. Three variables are tested: light, temperature and pH. The control is exposed to room light, room temperature, and neutral pH is also prepared. For each of the variables, a gradient is established providing a continuous variation from weak to strong intensities. Each habitat variable is applied to a 100 cm clear plastic tube filled with water and brine shrimp. The ends of the plastic tube possess extremes of a continuous variation in the habitat property. After the brine shrimp have been exposed to the habitat condition, they are divide into four groups by tightening three clamps around the tube at equal intervals. Each group is individually removed from the tube at equal intervals. Each group is individually removed from the tube and the number of live shrimp is counted.
    3. The histograms are prepared showing the number of brine shrimp in each of the four intensities. A histogram is prepared for each of the three variables and the control. From the data in the histograms, conclusions cab be made describing the habitat preferences of the brine shrimp

Sample Multiple - Choice Questions

  1. Artemia brine shrimp are rarely found in bodies of water with salt concentrations below 5%.
    1. This is probably because the brine shrimp prefer low levels of salt concentration
    2. The brine shrimp prefer high levels of salt concentration
    3. The brine shrimp cannot survive in fresh water
    4. The brine shrimp cannot survive in temperatures found in bodies of water with fresh water or water with low salinity
    5. Predators of the brine shrimp are common in fresh water and water with low salinity

Laboratory 12: Dissolved Oxygen and Aquatic Primary Productivity

Overview

You will measure and analyze the dissolved oxygen concentration in water samples using the Winkler technique. You will also measure and analyze the primary productivity of natural waters or lab cultures

Objectives

Results

The amount of oxygen dissolved in natural water samples is measured and analyzed to determine the primary productivity of the sample. The amount of dissolved oxygen is dependent upon many factors.

Primary productivity is a measure of the amount of biomass produced by autotrophs through photosynthesis per unit time. It can be examined by the following factors

    1. Gross Primary Productivity
    2. Net Primary Productivity
    3. Respiratory Rate

These determine primary productivity

    1. The Winkler Method—this is use to measure dissolved oxygen using a titration technique. Titration is the process of adding a substance of known concentration to a solution containing a substance of unknown concentration until a specific reaction is completed and a color change occurs
    2. The light and dark bottle method
    3. Initial bottle
    4. Light bottle
    5. Dark bottle

Sample Multiple - Choice Questions

  1. The net primary productivity for a temperate forest was measured at 2000 mg C/m2/day. The respiratory rate of the community was determined to be 1000 mg C/m2/day. The gross primary productivity for this community is
    1. 1000 mg C/m2/day
    2. 2000 mg C/m2/day
    3. 3000 mg C/m2/day
    4. 4000 mg C/m2/day
    5. 5000 mg C/m2/day

Answers

  1. (A) Water potential is highest in soil, decreases from root to leaf, and is lowest in the air. Water moves from the soil into the roots and through the plant an transpires from the leaf because water moves from the area of greatest water potential to the area of lowest water potential
  2. (B) The Q10 is the ratio of the metabolic rate at one temperature to the metabolic rate at a temperature 10° colder. A Q10 equal to 3 indicates that he metabolic rate triples when the body temperature increases by 10° C
  3. (E) The predators of brine shrimp cannot survive in bodies of water with high concentrations of sale. Thus, brine shrimp survive in bodies of water with a high salt concentration because predators are absent. In waters with low concentrations of salt, predators eliminate the brine shrimp
  4. (C) The gross primary productivity is the sum of the net primary productivity and the respiratory rate.