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AP Essay Questions
The following is a comprehensive list of essay questions that have been asked on past AP exams. The questions are organized according to units. Excuse the formatting. Feel free to paste this onto a word doc for an easier read
Unit 1 (Basic Chemistry and Water)
1. The unique properties (characteristics) of water make life possible on Earth. Select three properties of water and:
2. Describe the chemical composition and configuration of enzymes and discuss the factors that modify enzyme structure and/or function.
3. After an enzyme is mixed with its substrate, the amount of product formed is determined at 10-second intervals for 1 minute. Data from this experiment are shown below:
5. Describe the fluid-mosaic model of a plasma membrane. Discuss the role of the membrane in the movement of materials through it by each of the following processes:
7. Discuss 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.
10. Describe the similarities and differences between the biochemical pathways of aerobic respiration and photosynthesis in eukaryotic cells. Include in your discussion the major reactions, the end products, and energy transfers.
11. The rate of photosynthesis may vary with changes that occur in environmental temperature, wavelength of light, and light intensity. Using a photosynthetic organism of your choice, choose only ONE of the three variables (temperature, wavelength of light, or light intensity) and for this variable
13. Explain what occurs during the Krebs (citric acid) cycle and electron transport by describing the following:
20. An organism is heterozygous at two genetic loci on different chromosomes.
23. Scientists seeking to determine which molecule is responsible for the transmission of characteristics from one generation to the next knew that the molecule must (1) copy itself precisely, (2) be stable but able to be changed, and (3) be complex enough to determine the organism’s phenotype.
24. Describe the biochemical composition, structure, and replication of DNA. Discuss how recombinant DNA techniques may be used to correct a point mutation.
25. Describe the production and processing of a protein that will be exported from a eukaryotic cell. Begin with the separation of the messenger RNA from the DNA template and end with the release of the protein at the plasma membrane.
26. Describe the steps of protein synthesis, beginning with the attachment of a messenger RNA molecule to the small subunit of a ribosome and ending generalized with the release of the polypeptide from the ribosome. Include in your answer a discussion of how the different types of RNA function in this process.
27. The diagram below shows a segment of DNA with a total length of 4,900 base pairs. The arrows indicate reaction sites for two restriction enzymes (enzyme X and enzyme Y).
32. Do the following with reference to the Hardy-Weinberg model.
36. Scientists recently have proposed a reorganization of the phylogenetic system of classification to include the domain, a new taxonomic category higher (more inclusive) than the Kingdom category, as shown in the following diagram.
Universal Ancestor
Domain Bacteria Domain Archaea Domain Eukarya
(Eubacteria) (Archaebacteria) (Eukaryotes)
37. In the life cycles of a fern and a flowering plant, compare and contrast each of the following:
41. Describe the processes of fat and protein digestion and product absorption as they occur in the human stomach and small intestine. Include a discussion of the enzymatic reactions involved.
42. Describe the following mechanisms of response to foreign materials in the human body.
44. Many physioligical changes occur during exercise.
48. The evolutionary success of organisms depends on reproduction. Some groups of organisms reproduce asexually, some reproduce sexually, while others reproduce both sexually and asexually.
52. Describe the negative and positive feedback loops, and discuss how feedback mechanisms regulate each of the following.
54. Structure and function are related in the various organ systems of animals. Select two of the following four organ systems in vertebrates:
Unit 14 (Plant Structure and Function)
55. Relate the structure of an angiosperm leaf to each of the following:
58. Describe the effects of plant hormones on plant growth and development. Design an experiment to demonstrate the effect of one of these plant hormones on plant growth and development.
59. Trace the pathway in a flowering plant as the water moves from the soil through the tissues of the root, stem, and leaves to the atmosphere. Explain the mechanisms involved in conducting water through these tissues.
60. Discuss the adaptations that have enabled flowering plants to overcome the following problems associated with life on land.
65. Describe and give an example of each of the following. Include in your discussion the selection advantage of each.
67. Describe releasers, imprinting, and communications, as each of these terms relates to animal behavior. You may include in your answer a discussion of the classical studies of Niko Tinbergen, Konrad Lorenz, and Karl von Frisch.
68. Describe the biogeochemical cycles of carbon and nitrogen. Trace these elements from the point of their release from a decaying animal to their incorporation into a living animal.
69. Using an example for each, discuss the following ecological concepts.
71. Survival depends on the ability of an organism to respond to changes in its environment. Some plants flower in response to changes in day length. Some mammals may run or fight when frightened. For both of these examples, describe the physiological mechanisms involved in the response.
72. Interdependence in nature is illustrated by the transfer of energy through trophic levels. The diagram below depicts the transfer of energy in a food web of an Arctic lake located in Alaska (J )
Cumulative Essays
74. Describe how the following adaptations have increased the evolutionary success of the organisms that possess them. Include in your discussion the structure and function related to each adaptation.
79. The survival of organisms depends on regulatory mechanisms at various levels. Choose THREE from the following examples. Explain how each is regulated.
Unit 1 (Basic Chemistry and Water)
1. The unique properties (characteristics) of water make life possible on Earth. Select three properties of water and:
- for each property, identify and define the property and explain it in terms of the physical/chemical nature of water.
- for each property, describe one example of how the property affects the functioning of living organisms.
2. Describe the chemical composition and configuration of enzymes and discuss the factors that modify enzyme structure and/or function.
3. After an enzyme is mixed with its substrate, the amount of product formed is determined at 10-second intervals for 1 minute. Data from this experiment are shown below:
- Time (sec)0
- What is the initial rate of this enzymatic reaction?
- What is the rate after 50 seconds? Why is it different from the initial rate?
- What would be the effect on product formation if the enzyme where heated to a temperature of 100° C for 10 minutes before repeating the experiment? Why?
- How might altering the substrate concentration affect the rate of the reaction? Why?
- How might altering the pH affect the rate of the reaction? Why?
10
20
30
40
50
60
Product formed (mg)0.00
0.25
0.50
0.70
0.80
0.85
0.85
Draw a graph of these data and answer the following questions.
- Relate the chemical structure of an enzyme to its specificity and catalytic activity.
- Design a quantitative experiment to investigate the influence of pH or temperature on the activity of an enzyme.
- Describe what information concerning the structure of an enzyme could be inferred from your experiments.
5. Describe the fluid-mosaic model of a plasma membrane. Discuss the role of the membrane in the movement of materials through it by each of the following processes:
- Active transport
- Passive transport
7. Discuss 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.
- 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 experiments: and (c) an explanation of those results based on the principles involved. (Be sure to clearly state the principles addressed in your discussion.)
- Osmosis
- Active Transport
- Facilitated Diffusion
- Endocytosis/exocytosis
- Describe the transport process and explain how the organization of cell membranes functions in the movement of specific molecules across membranes; and
- Explain the significance of each type of transport to a specific cell (you may use difference cell types as examples.)
10. Describe the similarities and differences between the biochemical pathways of aerobic respiration and photosynthesis in eukaryotic cells. Include in your discussion the major reactions, the end products, and energy transfers.
11. The rate of photosynthesis may vary with changes that occur in environmental temperature, wavelength of light, and light intensity. Using a photosynthetic organism of your choice, choose only ONE of the three variables (temperature, wavelength of light, or light intensity) and for this variable
- design a scientific experiment to determine the effect of the variable on the rate of photosynthesis for the organism;
- explain how you would measure the rate of photosynthesis in your experiment;
- describe the results you would expect. Explain why you would expect these results.
13. Explain what occurs during the Krebs (citric acid) cycle and electron transport by describing the following:
- The location of the Krebs cycle and electron transport chain in mitochondria.
- The cyclic nature of the reactions in the Krebs cycle.
- The production of ATP and reduced coenzymes during the cycle.
- The chemiosmotic production of ATP during electron transport.
- Describe how membrane structure is related to the transport of materials across the membrane.
- Describe the role of membranes in the synthesis of ATP in either cellular respiration or photosynthesis.
- cellular movement
- active transport
- synthesis of molecules
- chemiosmosis
- fermentation
- Cumulative Oxygen Consumed (mL)
- Using the graph paper provided, plot the results for the germinating seeds at 22° C and at 10° C.
- Calculate function the rate of oxygen consumption for the germinating seeds at 22° C, using the time interval between 10 and 20 minutes.
- Account for the differences in oxygen consumption observed between:
- germinating seeds at 22° C and at 10° C
- germinating seeds and dry seeds
- 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.
Time (minutes)
0
10
20
30
40
22° C Germinating Seeds
0.0
8.8
16.0
23.7
32..0
Dry Seeds
0.0
0.2
0.1
0.0
0.1
10° C Germinating Seeds
0.0
2.9
6.2
9.4
12.5
Dry Seeds
0.0
0.0
0.2
0.1
0.2
- Autosomal linkage.
- Sex-linked (X-linked) inheritance.
- Polygenic (multiple-gene) inheritance.
- Hershey and Chase- bacteriophage replication
- Griffith and Avery, MacLeod and McCarty- bacterial transformation
- Meselson and Stahl- DNA replication in bacteria
20. An organism is heterozygous at two genetic loci on different chromosomes.
- Explain how these alleles are transmitted by the process of mitosis to daughter cells.
- Explain how these alleles are distributed by the process of meiosis to gametes.
- Explain how the behavior of these two pairs of homologous chromosomes during meiosis provides the physical basis for Mendel’s two laws of inheritance.
Unit 6 (Protein Synthesis, Gene Expression, DNA Technology)
- TAC GAA CTT GGG TCC
This DNA sequence codes for the following short polypeptide.
methionine - leucine - glutamic acid - proline - arginine
Describe the steps in the synthesis of this polypeptide. What would be the effect of a deletion or an addition in one of the DNA nucleotides? What would be the effects of a substitution in one of the nucleotides?
23. Scientists seeking to determine which molecule is responsible for the transmission of characteristics from one generation to the next knew that the molecule must (1) copy itself precisely, (2) be stable but able to be changed, and (3) be complex enough to determine the organism’s phenotype.
- Explain how DNA meets each of the three criteria stated above.
- Select one of the criteria stated above and describe experimental evidence used to determine that DNA is the hereditary material.
24. Describe the biochemical composition, structure, and replication of DNA. Discuss how recombinant DNA techniques may be used to correct a point mutation.
25. Describe the production and processing of a protein that will be exported from a eukaryotic cell. Begin with the separation of the messenger RNA from the DNA template and end with the release of the protein at the plasma membrane.
26. Describe the steps of protein synthesis, beginning with the attachment of a messenger RNA molecule to the small subunit of a ribosome and ending generalized with the release of the polypeptide from the ribosome. Include in your answer a discussion of how the different types of RNA function in this process.
27. The diagram below shows a segment of DNA with a total length of 4,900 base pairs. The arrows indicate reaction sites for two restriction enzymes (enzyme X and enzyme Y).
- Explain how the principles of gel electrophoresis allow for the separation of DNA fragments.
- Describe the results you would expect from the electrophoresis separation of fragments from the following treatments of the DNA segment above. Assume that the digestions occurred under appropriate conditions and went to completion.
- DNA digested with only enzyme X
- DNA digested with only enzyme Y
- DNA digested with enzyme X and enzyme Y combined
- Undigested DNA
- Explain both of the following.
- The mechanism of action of restriction enzymes.
- The different results you would expect if a mutation occurred at the recognition site for enzyme Y.
- Describe a procedure by which this can be done.
- Explain the purpose of each step of your procedure.
- Describe how you could determine whether the gene was successfully incorporated.
- Describe an example of how gene transfer and incorporation have been used in biomedical or commercial applications.
- Describe the most probable pattern of inheritance for this condition. Explain your reasoning. Include in your discussion a sample cross(es) sufficient to verify your proposed pattern.
- Explain how a mutation could cause this inability to digest starch.
- Describe how modern techniques of molecular biology could be used to determine whether the mutant allele is present in a given individual.
- Convergent evolution of organisms and Australia.
- Blood groups and genetic drift.
- Birds of prey and DDT.
- population genetics
- molecular biology
- comparative anatomy and embryology
32. Do the following with reference to the Hardy-Weinberg model.
- Indicate the conditions under which allelic frequencies (p and q) remain constant from one generation to the next.
- Calculate, showing all work, the frequencies of the alleles and the 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 the agouti is due to a dominant all, W.)
- 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?
- Explain the mechanisms that lead to evolutionary change.
- Describe how scientists use each of the following as evidence for evolution.
- Bacterial resistance to antibodies.
- Comparative biochemistry.
- The fossil record.
- Explain three cellular and/or molecular mechanisms that introduce variation into the gene pool of a plant or animal population.
- Explain the evolutionary mechanisms that can change the composition of the gene pool.
- Number of Individuals
- Identify an organism that might have been used to perform this experiment, and explain why this organism is a good choice for conducting this experiment.
- On the basis of the data, propose a hypothesis that explains the change in phenotypic frequency between generation 1 and generation 3.
- Is there evidence indicating whether or not this population is in Hardy-Weinberg equilibrium? Explain.
Generation
Dominant
Recessive
Total
1
51
49
100
2
280
0
280
3
240
80
320
4
300
100
400
5
360
120
480
36. Scientists recently have proposed a reorganization of the phylogenetic system of classification to include the domain, a new taxonomic category higher (more inclusive) than the Kingdom category, as shown in the following diagram.
Universal Ancestor
Domain Bacteria Domain Archaea Domain Eukarya
(Eubacteria) (Archaebacteria) (Eukaryotes)
- describe how this classification scheme presents different conclusions about the relationships among living organisms than those presented by the previous five-kingdom system of classification
- describe three kinds of evidence that were used to develop the taxonomic scheme above, and explain how this evidence was used. The evidence may be structural, physiological, molecular, and/or genetic.
- Describe four of the characteristics of the universal ancestor.
37. In the life cycles of a fern and a flowering plant, compare and contrast each of the following:
- The gametophyte generation.
- Sperm transport and fertilization.
- Embryo protection.
- Coelomate versus acoelomate body plan.
- Protostome versus deuterostome development.
- Radial versus bilateral symmetry.
- Explain how each of these pairs of features was important in constructing the phylogenetic tree shown below. Use specific examples from the tree in your discussion.
- Pair A: green algae---vascular plants
Pair B: prokaryotes---eukaryotes
Pair C: amphibians---reptiles
Unit 11 (Animal Nutrition, Circulation, Respiration, Immune System)
41. Describe the processes of fat and protein digestion and product absorption as they occur in the human stomach and small intestine. Include a discussion of the enzymatic reactions involved.
42. Describe the following mechanisms of response to foreign materials in the human body.
- The antigen-antibody response to a skin graft from another person.
- The reactions of the body leading to inflammation of a wound infected by bacteria.
44. Many physioligical changes occur during exercise.
- Design a controlled experiment to test the hypothesis that an exercise session causes short-term increases in heart rat and breathing rate in humans.
- Explain how at least three organ systems are affected by this increased physical activity and discuss interactions among these systems.
- Describe the events that occur during period I as the immune system responds to the initial exposure to the antigen.
- Describe the events that occur during period II following a second exposure to the same antigen.
- Explain how infection by the AIDS virus (HIV) affects the function of both T and B lymphocytes.
48. The evolutionary success of organisms depends on reproduction. Some groups of organisms reproduce asexually, some reproduce sexually, while others reproduce both sexually and asexually.
- Using THREE difference organisms, give an example of one organism that reproduces sexually, one that reproduces asexually, and one that reproduces BOTH sexually and asexually. For each organism given as an example, describe two reproductive adaptations. These adaptations may be behavioral, structural, and/or functional.
- What environmental conditions would favor sexual reproduction? Explain. What environmental conditions would favor asexual reproduction? Explain.
- Insulin---glucagon
- Parathyroid hormone---calcitonin
- Thyrotropin (TSH)---thyroxine (T4)
52. Describe the negative and positive feedback loops, and discuss how feedback mechanisms regulate each of the following.
- The menstrual cycle in nonpregnant human female.
- Blood glucose levels in humans.
54. Structure and function are related in the various organ systems of animals. Select two of the following four organ systems in vertebrates:
- respiratory
- digestive
- excretory
- nervous
Unit 14 (Plant Structure and Function)
55. Relate the structure of an angiosperm leaf to each of the following:
- Adaptations for photosynthesis and food storage.
- Adaptations for food translocation and water transport.
- Specialized adaptations to a desert environment.
- Phototropism
- Photoperiodism
58. Describe the effects of plant hormones on plant growth and development. Design an experiment to demonstrate the effect of one of these plant hormones on plant growth and development.
59. Trace the pathway in a flowering plant as the water moves from the soil through the tissues of the root, stem, and leaves to the atmosphere. Explain the mechanisms involved in conducting water through these tissues.
60. Discuss the adaptations that have enabled flowering plants to overcome the following problems associated with life on land.
- The absence of an aquatic environment for reproduction.
- The absence of an aquatic environment to support the plant body.
- Dehydration of the plant.
- Group I-Room conditions (light, low humidity, 20° C, and little air movement.)Group II-Room conditions with increased humidity.Group III-Room conditions with increased air movement (fan)Group IV-Room conditions with additional lightThe cumulative water loss due to transpiration of water from each plant was measured at 10-minute intervals for 30 minutes. Water loss was expressed as milliliters of water per square centimeter of leaf surface area. The data for all plants in Group I (room conditions) were averaged. The average cumulative water loss by the plants in Group I is presented in the table below.
- Construct and label a graph using the data for Group I. Using the same set of axes, draw and label three additional lines representing the results that you would predict for Groups II, III, and IV.
- Explain how biological and physical processes are responsible for the difference between each of your predictions and the data for Group I.
- Explain how the concept of water potential is used to account for the movement of water from the plant stem to the atmosphere during transpiration.
Average Cumulative Water Loss by the Plants in Group I
Time (minutes)
Average Cumulative Water Loss (milliliter H2O centimeter2)
10
3.5 x 10-4
20
7.7 x 10-4
30
10.6 x 10-4
- Plant Seedling Mass (grams)Day 1Day 30Student A424Student B535Student C464
- Identify three different environmental variables that could account for differences in the mass of seedlings at day 30. Then choose one of these variables and design an experiment to test the hypothesis that your variable affects growth of these seedlings.
- Discuss the results you would expect if your hypothesis is correct. Then provide a physiological explanation for the effect of your variable on plant growth.
- Territoriality.
- Dominance hierarchies.
- Courtship behavior.
65. Describe and give an example of each of the following. Include in your discussion the selection advantage of each.
- Pheromones.
- Mimicry.
- Stereotyped behavior (instinct).
67. Describe releasers, imprinting, and communications, as each of these terms relates to animal behavior. You may include in your answer a discussion of the classical studies of Niko Tinbergen, Konrad Lorenz, and Karl von Frisch.
68. Describe the biogeochemical cycles of carbon and nitrogen. Trace these elements from the point of their release from a decaying animal to their incorporation into a living animal.
69. Using an example for each, discuss the following ecological concepts.
- Succession
- Energy flow between trophic levels.
- Limiting factors.
- Carrying capacity.
71. Survival depends on the ability of an organism to respond to changes in its environment. Some plants flower in response to changes in day length. Some mammals may run or fight when frightened. For both of these examples, describe the physiological mechanisms involved in the response.
72. Interdependence in nature is illustrated by the transfer of energy through trophic levels. The diagram below depicts the transfer of energy in a food web of an Arctic lake located in Alaska (J )
- Choosing organisms from four different trophic levels of this food web as examples, explain how energy is obtained at each trophic level.
- Describe the efficiency of energy transfer between trophic levels and discuss how the amount of energy available at each trophic level affects the structure of the ecosystem.
- If the cells in the dead terrestrial plant material that washed into the lake contained a commercially produced toxin, what would be the likely effects of this toxin on this food web? Explain.
- Noon
174.0
4 p.m.
350.5
8 p.m.
60.5
midnight
8.0
- Summarize the pattern.
- Identify THREE physiological or environmental variables that could cause the slugs to vary their distance from each other.
- Explain how each variable could bring about the observed pattern of distribution.
Cumulative Essays
74. Describe how the following adaptations have increased the evolutionary success of the organisms that possess them. Include in your discussion the structure and function related to each adaptation.
- C4 metabolism
- Amniotic egg
- Four-chambered heart
- Pollen
- Artery---vein
- Small intestine---colon
- Skeletal muscle---cardiac muscle
- Anterior pituitary---posterior pituitary
- seeds
- mammalian placenta
- diploidy
- Discuss the type of nutrition and the nutritional requirements of angiosperms and vertebrates.
- Describe 2 structural adaptations in angiosperms for obtaining nutrients from the environment. Relate structure to function.
- Interdependence in nature is evident in symbiosis. Explain tow symbiotic relationships that aid in nutrient uptake, using examples from angiosperms and/or vertebrates. (Both examples may be angiosperms, both may be vertebrates, or one may be from each group.
79. The survival of organisms depends on regulatory mechanisms at various levels. Choose THREE from the following examples. Explain how each is regulated.
- The expression of a gene.
- The activity of an enzyme.
- The cell cycle.
- The internal water balance of a plant.
- The density of a population.
- Explain how the metabolic processes of cellular respiration and photosynthesis recycle oxygen.
- Discuss the structural adaptations that function in oxygen exchange between each of the following organisms and its environment: a plant; an insect; a fish.
- Trace a molecule of O2 from the environment to a muscle cell in a vertebrate of your choice.
- Organisms recognize others as members of their own species.
- Neurotransmitters are recognized in the synapse.
- Antigens trigger antibody response.
- Nucleic acids are complementary.
- Target cells respond to specific hormones.
- communication between two plant cells
- communication between two immune-system cells
- communication either between a neuron and another neuron, or between a neuron and a muscle cell
- communication between a specific endocrine-gland cell and its target cell