AP Essay Questions

AP Biology 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.

There are writing services with the best writers:

Unit 1 (Basic Chemistry and Water)

1.  The unique properties (characteristics) of water make life possible on Earth. Select three properties of water and:

      1. for each property, identify and define the property and explain it in terms of the physical/chemical nature of water.
      2. for each property, describe one example of how the property affects the functioning of living organisms.

Unit 2 (Organic Chemistry, Biochemistry, and Metabolism)

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)0102030405060
Product formed (mg)0.000.250.500.700.800.850.85

Draw a graph of these data and answer the following questions.

    1. What is the initial rate of this enzymatic reaction?
    2. What is the rate after 50 seconds? Why is it different from the initial rate?
    3. 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?
    4. How might altering the substrate concentration affect the rate of the reaction? Why?
    5. How might altering the pH affect the rate of the reaction? Why?

4.  Enzymes are biological catalysts.

  1. Relate the chemical structure of an enzyme to its specificity and catalytic activity.
  2. Design a quantitative experiment to investigate the influence of pH or temperature on the activity of an enzyme.
  3. Describe what information concerning the structure of an enzyme could be inferred from your experiments.

Unit 3 (Cell Structure and Function, Cell division)

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:

  1. Active transport
  2. Passive transport

6.  Describe the structure of a eukaryotic plant cell. Indicate the ways in which a nonphotosynthetic prokaryotic cell would differ in structure from this generalized eukaryotic plant cell.

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.

8.  A laboratory assistant prepared solution 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 experiments: and (c) an explanation of those results based on the principles involved. (Be sure to clearly state the principles addressed in your discussion.)

9.  Cells transport substances across their membranes. Choose THREE of the following four types of cellular transport.

    • Osmosis
    • Active Transport
    • Facilitated Diffusion
    • Endocytosis/exocytosis

For each of the three transport types you choose,

    1. Describe the transport process and explain how the organization of cell membranes functions in the movement of specific molecules across membranes; and
    2. Explain the significance of each type of transport to a specific cell (you may use difference cell types as examples.)

Unit 4 (Photosynthesis and Cellular Respiration)

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.

12.  Describe the light reactions of photosynthesis and, for both a C3 and a C4 plant, trace the path of a carbon dioxide molecule from the point at which it enters a plant to its incorporation into a glucose molecule. Include leaf anatomy and biochemical pathways in your discussion of each type of plant.

13.  Explain what occurs during the Krebs (citric acid) cycle and electron transport by describing the following:

    1. The location of the Krebs cycle and electron transport chain in mitochondria.
    2. The cyclic nature of the reactions in the Krebs cycle.
    3. The production of ATP and reduced coenzymes during the cycle.
    4. The chemiosmotic production of ATP during electron transport.

14.  Membranes are important structural features of cells.

    1. Describe how membrane structure is related to the transport of materials across the membrane.
    2. Describe the role of membranes in the synthesis of ATP in either cellular respiration or photosynthesis.

15. Energy transfer occurs in all cellular activities. For 3 of the following 5 processes involving energy transfer, explain how each functions in the cell and give an example. Explain how ATP is involved in each example you choose.

        • cellular movement
        • active transport
        • synthesis of molecules
        • chemiosmosis
        • fermentation

16. 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.

Cumulative Oxygen Consumed (mL)

Time (minutes)010203040
22° C Germinating Seeds0.08.816.023.732..0
Dry Seeds0.00.20.10.00.1
10° C Germinating Seeds0.02.96.29.412.5
Dry Seeds0.00.00.20.10.2
      1. Using the graph paper provided, plot the results for the germinating seeds at 22° C and at 10° C.
      2. Calculate function the rate of oxygen consumption for the germinating seeds at 22° C, using the time interval between 10 and 20 minutes.
      3. 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
      4. 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.

Unit 5 (Meiosis, Mendelian Genetics, DNA Replication)

17.  State the conclusions reached by Mendel in his work on the inheritance of characteristics. Explain how each of the following deviates from these conclusions.

    1. Autosomal linkage.
    2. Sex-linked (X-linked) inheritance.
    3. Polygenic (multiple-gene) inheritance.

18.  Experiments by the following scientists provided critical information concerning DNA. Describe each classical experiment and indicate how it provided evidence for the chemical nature of the gene.

    1. Hershey and Chase- bacteriophage replication
    2. Griffith and Avery, MacLeod and McCarty- bacterial transformation
    3. Meselson and Stahl- DNA replication in bacteria

19.  Discuss Mendel’s laws of segregation and independent assortment. Explain how the events of meiosis I account for the observations that led Mendel to formulate these laws.

20.  An organism is heterozygous at two genetic loci on different chromosomes.

      1. Explain how these alleles are transmitted by the process of mitosis to daughter cells.
      2. Explain how these alleles are distributed by the process of meiosis to gametes.
      3. Explain how the behavior of these two pairs of homologous chromosomes during meiosis provides the physical basis for Mendel’s two laws of inheritance.

Labeled diagrams that are explained in your answer may be useful.

Unit 6 (Protein Synthesis, Gene Expression, DNA Technology)

21.  A portion of specific DNA molecule consists of the following sequence of nucleotide triplets.

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?

22.  Describe the operon hypothesis and discuss how it explains the control of messenger RNA production and the regulation of protein synthesis in bacterial cells.

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).

    1. Explain how the principles of gel electrophoresis allow for the separation of DNA fragments.
    2. 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.
      1. DNA digested with only enzyme X
      2. DNA digested with only enzyme Y
      3. DNA digested with enzyme X and enzyme Y combined
      4. Undigested DNA
    3. Explain both of the following.
      1. The mechanism of action of restriction enzymes.
      2. The different results you would expect if a mutation occurred at the recognition site for enzyme Y.

28.  By using the techniques of genetic engineering, scientists are able to modify genetic materials so that a particular gene of interest from one cell can be incorporated into a different cell.

        • 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.

29.  Assume that a particular genetic condition in a mammalian species causes an inability to digest starch. This disorder occurs with equal frequency in males and females. In most cases, neither parent of affected offspring has the condition.

      1. 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.
      2. Explain how a mutation could cause this inability to digest starch.
      3. Describe how modern techniques of molecular biology could be used to determine whether the mutant allele is present in a given individual.

Unit 7 (Evolution, Population Genetics, Speciation)

29.  Describe the special relationship between the two terms in each of the following pairs.

    1. Convergent evolution of organisms and Australia.
    2. Blood groups and genetic drift.
    3. Birds of prey and DDT.

30.  Describe the modern theory of evolution and discuss how it is supported by evidence from two of the following areas.

    1. population genetics
    2. molecular biology
    3. comparative anatomy and embryology

31.  Describe the process of speciation. Include in your discussion the factors that may contribute to the maintenance of genetic isolation.

32.  Do the following with reference to the Hardy-Weinberg model.

    1. Indicate the conditions under which allelic frequencies (p and q) remain constant from one generation to the next.
    2. 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.)
    3. 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?

33.  Evolution is one of the major unifying themes of modern biology.

    1. Explain the mechanisms that lead to evolutionary change.
    2. Describe how scientists use each of the following as evidence for evolution.
      1. Bacterial resistance to antibodies.
      2. Comparative biochemistry.
      3. The fossil record.

34.  Genetic variation is the raw material for evolution.

    1. Explain three cellular and/or molecular mechanisms that introduce variation into the gene pool of a plant or animal population.
    2. Explain the evolutionary mechanisms that can change the composition of the gene pool.

35.  In a laboratory population of diploid, sexually reproducing organisms a certain trait is studied. This trait is determined by a single autosomal gene and is expressed as two phenotypes. A new population was created by crossing 51 pure breeding (homozygous) dominant individuals with 49 pure breeding (homozygous) individuals. After four generations, the following results were obtained.

Number of Individuals

GenerationDominantRecessiveTotal
15149100
22800280
324080320
4300100400
5360120480
    1. 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.
    2. On the basis of the data, propose a hypothesis that explains the change in phenotypic frequency between generation 1 and generation 3.
    3. Is there evidence indicating whether or not this population is in Hardy-Weinberg equilibrium? Explain.

 Unit 8 (Chemical Evolution, Prokaryotes, Eukaryote Evolution, Protista)

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.

Unit 9 (Introduction to Plants, Fungi, Invertebrates)

37.  In the life cycles of a fern and a flowering plant, compare and contrast each of the following:

    1. The gametophyte generation.
    2. Sperm transport and fertilization.
    3. Embryo protection.

38.  Describe the differences between the terms in each of the following pairs.

      1. Coelomate versus acoelomate body plan.
      2. Protostome versus deuterostome development.
      3. Radial versus bilateral symmetry.
      4. 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.

Unit 10 (Vertebrates, Basic Animal Structure and Function)

39.  Select two of the following three pairs and discuss the evolutionary relationships between the two members of each pair you have chosen. In your discussion include structural adaptations and the functional significance.

Pair A: green algae—vascular plants

Pair B: prokaryotes—eukaryotes

Pair C: amphibians—reptiles

Unit 11 (Animal Nutrition, Circulation, Respiration, Immune System)

40.  Describe the structure of a mammalian respiratory system. Include in your discussion the mechanisms of inspiration and expiration.

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.

    1. The antigen-antibody response to a skin graft from another person.
    2. The reactions of the body leading to inflammation of a wound infected by bacteria.

43.  Discuss the processes of exchange of O2 and CO2 that occur at the alveoli and muscle cells of mammals. Include in your answer a description of the transport of these gases in the blood.

44.  Many physioligical changes occur during exercise.

    1. Design a controlled experiment to test the hypothesis that an exercise session causes short-term increases in heart rat and breathing rate in humans.
    2. Explain how at least three organ systems are affected by this increased physical activity and discuss interactions among these systems.

45.  The graph below shows the response of the human immune system to exposure to an antigen. Use this graph to answer part a and part b of this question.

      1. Describe the events that occur during period I as the immune system responds to the initial exposure to the antigen.
      2. Describe the events that occur during period II following a second exposure to the same antigen.
      3. Explain how infection by the AIDS virus (HIV) affects the function of both T and B lymphocytes.

Unit 12 (Homeostasis, Reproduction, Development)

47.  Discuss the processes of cleavage, gastrulation, and neurulation in the frog embryo; tell what each process accomplishes. Describe an experiment that illustrates the importance of induction in development.

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.

      1. 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.
      2. What environmental conditions would favor sexual reproduction? Explain. What environmental conditions would favor asexual reproduction? Explain.

Unit 13 (Endocrine System, Nervous System, Sensory and Motor Mechanisms)

49.  Discuss the sources and actions of each of the following pairs of hormones in humans and describe the feedback mechanisms that control their release.

    1. Insulin—glucagon
    2. Parathyroid hormone—calcitonin
    3. Thyrotropin (TSH)—thyroxine (T4)

50.  Beginning at the presynaptic membrane of the neuromuscular junction, describe the physical and biochemical events involved in the contraction of a skeletal muscle fiber. Include the structure of the fiber in your discussion.

52.  Describe the negative and positive feedback loops, and discuss how feedback mechanisms regulate each of the following.

    1. The menstrual cycle in nonpregnant human female.
    2. Blood glucose levels in humans.

53.  Discuss how cellular structures, including the plasma membrane, specialized endoplasmic reticulum, cytoskeletal elements, and mitochondria, function together in the contraction of skeletal muscle cells.

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

For each of the two systems you choose, discuss the structure and function of two adaptations that aid in the transport or exchange of molecules (or ions). Be sure to relate structure to function in each example.

Unit 14 (Plant Structure and Function)

55.  Relate the structure of an angiosperm leaf to each of the following:

    1. Adaptations for photosynthesis and food storage.
    2. Adaptations for food translocation and water transport.
    3. Specialized adaptations to a desert environment.

56.  Define the following plant responses and explain the mechanism of control for each. Cite experimental evidence as part of your discussion.

    1. Phototropism
    2. Photoperiodism

57.  Describe the structure of a bean seed and discuss its germination to the seedling stage. Include in your essay hormonal controls, structural changes, and tissue differentiation.

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.

    1. The absence of an aquatic environment for reproduction.
    2. The absence of an aquatic environment to support the plant body.
    3. Dehydration of the plant.

61.  A group of students designed an experiment to measure transpiration rates in a particular species of herbaceous plant. Plants were divided into four groups and were exposed to the following conditions.

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 light

The 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.

Average Cumulative Water Loss by the Plants in Group I
Time (minutes)Average Cumulative Water Loss (milliliter H2O centimeter2)
103.5 x 10-4
207.7 x 10-4
3010.6 x 10-4
    1. 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.
    2. Explain how biological and physical processes are responsible for the difference between each of your predictions and the data for Group I.
    3. 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.

62.  Numerous environmental variables influence plant growth. Three students each planted a seedling of the same genetic variety in the same type of container with equal amounts of soil from the same source. Their goal was to maximize their seedling’s growth by manipulating environmental conditions. Their data are shown below.

Plant Seedling Mass (grams)
Day 1Day 30
Student A424
Student B535
Student C464
      1. 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.
      2. 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.

Unit 15 (Ecology)

63.  Define and explain the role of each of the following in social behavior.

    1. Territoriality.
    2. Dominance hierarchies.
    3. Courtship behavior.

64.  Describe the trophic levels in a typical ecosystem. Discuss the flow of energy through the ecosystem, the relationship between the different trophic levels, and the factors that limit the number of trophic levels.

65.  Describe and give an example of each of the following. Include in your discussion the selection advantage of each.

    1. Pheromones.
    2. Mimicry.
    3. Stereotyped behavior (instinct).

66.  Describe the process of ecological succession from a pioneer community to a climax community. Include in your answer a discussion of species diversity and interactions, accumulation of biomass, and energy flow.

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.

    1. Succession
    2. Energy flow between trophic levels.
    3. Limiting factors.
    4. Carrying capacity.

70.  Living organisms play an important role in the recycling of many elements within an ecosystem. Discuss how various types of organisms and their biochemical reactions contribute to the recycling of either carbon or nitrogen in an ecosystem. Include in your answer one way in which human activity has an impact in the nutrient cycle you have chosen.

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 )

      1. Choosing organisms from four different trophic levels of this food web as examples, explain how energy is obtained at each trophic level.
      2. 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.
      3. 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.
Noon174.0
4 p.m.350.5
8 p.m.60.5
midnight8.0

For the data above, provide information on each of the following.

    • 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.

Choose ONE of the variables that you identified and design a controlled experiment to test your hypothetical explanation. Describe results that would support or refute your hypothesis.

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.

    1. C4 metabolism
    2. Amniotic egg
    3. Four-chambered heart
    4. Pollen

75.  Describe the anatomical and functional similarities and difference within each of the following pairs of structures.

    1. Artery—vein
    2. Small intestine—colon
    3. Skeletal muscle—cardiac muscle
    4. Anterior pituitary—posterior pituitary

76.  Discuss how each of the following has contributed to the evolutionary success of the organisms in which they are found.

    1. seeds
    2. mammalian placenta
    3. diploidy

77.  Angiosperms (flowering plants) and vertebrates obtain nutrients from their environment in different ways.

    1. Discuss the type of nutrition and the nutritional requirements of angiosperms and vertebrates.
    2. Describe 2 structural adaptations in angiosperms for obtaining nutrients from the environment. Relate structure to function.
    3. 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.

78.  The problem of survival of animals on land are very different from those of survival of animals in an aquatic environment. Describe four problems associated with animal survival in terrestrial environments but not in aquatic environments. For each problem, explain an evolutionary solution.

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.

80.  Photosynthesis and cellular respiration recycle oxygen in ecosystems. Respond to TWO (and only two) of the following:

    1. Explain how the metabolic processes of cellular respiration and photosynthesis recycle oxygen.
    2. Discuss the structural adaptations that function in oxygen exchange between each of the following organisms and its environment: a plant; an insect; a fish.
    3. Trace a molecule of O2 from the environment to a muscle cell in a vertebrate of your choice.

81.  Biological recognition is important in many processes at the molecular, cellular, tissue, and organismal levels. Select three of the following, and for each of the three that you have chose, explain how the process of recognition occurs and give an example of each.

    1. Organisms recognize others as members of their own species.
    2. Neurotransmitters are recognized in the synapse.
    3. Antigens trigger antibody response.
    4. Nucleic acids are complementary.
    5. Target cells respond to specific hormones.

82.  Communication occurs among the cells in a multicellular organism. Choose THREE of the following examples of cell-to-cell communication, and for each example, describe the communication that occurs and the types of responses that result from this communication.

  • 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

 

Back

Six Resources with the Best AP Textbook Prices

Advanced Placement classes were once limited to select groups of students, but today, these classes dominate the high school experience. During the 2016-2017 school year, 111,000 students in American schools took the computer science course with a growth of more than 54,000 students from the previous year. We’ve put together a list of excellent resources for finding the best AP Biology textbook prices including some brand-new publishers that focus on cutting the costs of AP courses.

Biology and other sciences are also on the rise. A total of 2.7 million students took five million AP exams according to College Board, the test designer and proctor.

Unfortunately, growth in enrolment hasn’t meant a decline in costs. While some low income students see their test fees covered, recent cuts from the Every StudentSucceedsAct mean that some students need additional dollars.

Finding financially accessible textbooks has never been more critical as more students prepare for more AP tests. Fortunately, these textbooks don’t have to break the bank and with greater student enrolment comes more options for new books.

Six Places to Find the Best AP Textbook Prices

Searching for your AP biology book and think you might get a better price? Check out these resources before placing your order.

[amazon box=”1524757950,1524757969,0133458148,1438079206,0544784685,194755610X” grid=”2″]

Amazon

amazon-logo

image by: Amazon

Buying AP biology test books from Amazon means you have access to almost every brand and publisher imaginable including off-the-beaten-path books. You’re not only offered the most up-to-date editions of each book, but they come in various formats. Both comprehensive reviews and Cliff’s Notes versions of each book are available online.

Why buy Amazon?

Amazon offers excellent back-to-school prices and a simple returns policy. If you’re a Prime member, you’ll also benefit from free, fast shipping.

Additionally, Amazon hosts customer reviews that give you insight into the book. If you’re looking for complete coverage in specific areas or a particular learning style, the reviews section provides excellent coverage of what it’s like to use the book.

Finally, some books come in both used and new varieties as well as Kindle editions, so there are plenty of ways to save extra cash or even get more books.

Google Books

Google_Book

image by: Google books

Buying the digital version of AP books is a great way to save money and make test prep more accessible wherever you are.

Google Books offers a range of AP test prep e-books including AP Biology. Google’s library hosts most of the major test prep brands including:

  • Kaplan
  • Barron’s
  • CliffsNotes
  • The Princeton Review
  • McGraw Hill

There are also plenty of unknown authors that offer a different or cheaper way to study.

You can access Google Books on any device as long as you log into your Google account. You can even use them on your computer if you prefer a bigger screen. Visit the desktop version of the Google Play store for access.

Google Books also offers refunds on unread books. If you find digital versions don’t work for you or you’re one chapter into a book unsuited to your learning style, it’s possible to return it. Visit the My Account section the Google Play store and click the item you want to return.

You may return any e-book up to seven days after buying it. E-book rentals are final sales. If the e-book malfunctions, you may receive a refund within 65 days of the purchase date.

Textbooks.com

textbook.com

image by: textbook

Looking for an AP Biology textbook rather than test prep?

Visit Textbooks.com to search through the vast marketplace of competitively priced books. You’ll find new, used, and e-book versions of most of the primary textbooks all from different sellers.

Type “AP biology” into the search bar to find precisely what you need. When we last looked, 274 results were available and included:

  • Biology (AP 11thEdition) (Mader)
  • Cliff’s AP: Biology (2ndEdition)
  • SparkNotes Guide to AP Biology
  • Barron’s AP Biology
  • Campbell Biology, AP Edition
  • Cracking the AP Biology Exam 2017

Textbooks.com offers the best prices we’ve seen with some books.

While the prices can’t be beaten, it’s good to be wary of buying used books. While used books are ideal, an older book might miss something covered on the test. New books tend to include the latest edition of the test more precisely as well, which helps give you an edge.

eBay

EBay_logo

image by: ebay

If one internet giant comes to mind for textbook purchases, it’s Amazon. But eBay is also an excellent resource for AP biology books. Much of what you’ll find on eBay falls under the category of gently used, but our searches showed that you’re more likely to get the very latest version of the book on eBay compared to other sites.

eBay was partly eclipsed by Amazon because it relied so heavily on seller’s ability to ship things in good time. Shipping was also previously based on zip codes. It quickly made up the bulk of the price on cheaper items.

Today, free shipping is standard on eBay items including on AP history books.

Why choose eBay over Amazon or another used book marketplace?

eBay demands more of a description of the book before posting. Amazon and other sellers tend to note whether the book is in excellent, good, or poor condition. On eBay, sellers indicate the state of the book, but many also describe any damage to the book such as any writing included in the book or if the cover is frayed.

Buying a New Book and Worried About the Price?

If the price of a textbook seems to good to be true, it often isn’t. Bookstores tend to sell U.S. versions of textbooks featuring hardcovers and quality materials. The international version, which is what is usually found significantly cheaper on eBay, is a softcover with cheaper paper. In most cases, the international version is a carbon copy of the same book. Some anomalies arise, but you are likely to see those in the seller reviews.

Regardless of where you buy, double check the edition to make sure it’s not a reprint. Fortunately, most AP course books include the date or version on the cover, so it’s easy to spot in the photos.

OpenStax

OpenStax

image by: openstax

Have you already looked at Barron’s, the Princeton Review, Cliff Notes, and others without finding much success?

AP biology students now have a new option: OpenStax.

OpenStax is a non-profit textbook developer from Rice University. Their goal is to improve access to AP tests, college, and education generally by providing open-licensed college textbooks. Because these books are open-license and OpenStax isn’t out to make money, you’ll receive a high quality, current book for far less money than traditional textbooks.

OpenStax started out providing STEM subjects including biology. Today, they are available for many AP topics including:

  • Biology
  • Physics
  • Macroeconomics
  • SparkNotes Guide to AP Biology

These books aren’t just test prep books. They’re suitable for students taking AP or college courses to prepare for the tests.

The OpenStax Biology for AP® Courses book covers all the requirements of the standard two-semester AP course. It meets core concepts and foundational research and uses the evolutionary lens mandated by AP. The company designed its book not just to meet but exceed the requirements set by College Board, which makes it an essential learning book and an excellent companion to AP study books for those working independently.

HOW MUCH WILL YOU PAY FOR THESE HIGH-QUALITY BOOKS?

Students are expected to pay nothing. These books are free and licensed under Creative Commons, which means everyone has access to them.

Before you worry about quality, don’t. Each book is written by experts in their field. The content is sourced and vetted by peer reviewers, just like the traditional course books you’d otherwise buy.

In 2016 alone, 392,000 students used these books to save a good amount of money. So, head over to OpenStax, and give them a try.

Pearson

pearson-logo

Pearson is an industry-leading education company that publishes books known for their academic rigor. Their AP® Honors & Electives series is no different.Each Pearson book comes with a both an AP Exam Preparation Guide and Test Prep Workbook written according to the College Board course outline. Inside the books, you’ll find:

  • Overview of the program
  • Test-taking tips
  • Strategies for achieving the best score
  • Practice tests

Pearson’s test prep series is competitively priced and maybe even cheaper if you find yourself a promo code.

Are You Ready for Your AP Exam?

[amazon fields=”1438008686″ value=”thumb” image_size=”large”]

AP classes aim to prepare you for the exam, but the help of test prep books and a good textbook are invaluable to the process. While exam prices continue to climb, test prep books remain competitive, and some quality materials are now free to all student.

What books would you recommend for scoring a 5 on an AP Biology exam? Share your favorite study materials and tricks in the comments below.

Earthworm Anatomy and Dissection Guide

Earthworm Dissection and Earthworm Anatomy

Pictures: Modern Biology, Holt

The following is a classification of a species in the earthworm family Lumbricidae. This common species is Lumbricus terrestris also known as the night crawler or dew worm. In this article, we will cover earthworm anatomy and an introduction on dissecting an earthworm. 

Phylum –
Class –
Family –
Genus –
Species –
Annelida
Oligochaeta
Lumbricidae
Lumbricus
terrestris

Objectives:

 

In this earthworm dissection guide, you will learn to:


• Describe the appearance of various organs found in the earthworm.
• Name the organs that make up various systems of the earthworm.

Materials:
Safety goggles, dissecting pins, gloves, forceps, lab safety apron, scissors, paper towel, scalpel, water, dissecting probe, preserved earthworm, hand lens, dissection tray.

Purpose:
In this lab, you will dissect an earthworm in order to observe the external and internal structures of earthworm anatomy, whilst following the all-important lab safety procedures.

 

This guide is perfect for students in colleges or universities. 

 

 

Background:


Among the most familiar invertebrate animals are the earthworms, members of the phylum Annelida. The word annelida means “ringed” and refers to a series of rings or segments that make up the bodies of the members of this phylum. Internally, septa, or dividing walls, are located between the segments. External segments are called metameres. There may be more than 100 segments in an adult worm. The clitellum is a swelling of the body found in sexually mature worms and is active in the formation of an egg capsule, or cocoon. This is the earthworm reproductive organ. Eggs are produced in the ovaries and pass out of the body through female genital pores. Sperm are produced in the testes and pass out through tiny male genital pores. During mating, sperm from one worm travel along the sperm grooves to the seminal receptacles of another worm. Fertilization of the eggs takes place outside the body as the cocoon moves forward over the body, picking up the eggs of one worm and the sperm of its mate. The pumping organs of the circulatory system are five aortic arches. Circulatory fluids travel from the arches through the ventral blood vessel to capillary beds in the body. The fluids then collect in the dorsal blood vessel and reenter the aortic arches. The earthworm takes in a mixture of soil and organic matter through its mouth, which is the beginning of the digestive tract. The mixture enters the pharynx, which is located in segments 1–6. The esophagus, in segments 6–13, acts as a passageway between the pharynx esophagus and the crop. The crop stores food temporarily. The mixture that the earthworm ingests is ground up in the gizzard. In the intestine, which extends over two-thirds of the body length, digestion and absorption take place. Soil particles and undigested organic matter pass out of the worm through the rectum and anus. The nervous system consists of the ventral nerve cord, which travels the length of the worm on the ventral side, and a series of ganglia, which are masses of tissue containing many nerve cells. The nerve collar surrounds the pharynx esophagus and consists of ganglia above and below the pharynx. Nervous impulses are responsible for movement and responses to stimuli. Each segment contains an enlargement, or ganglion, along the ventral nerve cord. Excretory functions are carried on by nephridia, which are found in pairs in each body segment. They appear as tiny white fibers on the dorsal body wall. The earthworm has no gills or lungs. Gases are exchanged between the circulatory system and the environment through the moist skin.

earthworm anatomy

 

External Earthworm Anatomy

 

What is the external anatomy of an earthworm?

 

The external body of an earthworm is well adapted for living in the soil, similar to the external structure of other insects. The front or head of the worm is called the anterior. The very first section of the anterior contains the mouth and prostomium. The prostomium is a kind of lip which is located on the front of the mouth. Earthworms lose moisture and breathe via their skin. They have light-sensitive cells across their external structure, which are scattered around the skin. These cells give earthworms the ability to detect changes in lighting, and these cells are also sensitive to chemicals and touch. The body is separated in segments which resemble rings. Each segment has a number of bristly hairs attached to it, which helps the earthworm to move around. On mature earthworms, you will find a saddle or glandular ring called a clitellum. When an earthworm has mated, the clitellum will secrete a sack of eggs. The final segment of an earthworm contains the anus which is where waste is secreted. 

 

Dissection Guide:


1. Put on safety goggles, gloves, and a lab apron.

2. Place earthworm in the dissecting tray & rinse off the excess preservative. Identify the dorsal side, which is the worm’s rounded top, and the ventral side, which is its flattened bottom. Turn the worm ventral side up, as shown in the earthworm anatomy diagram below.

earthworm anatomy

3. Use a hand lens as you observe all parts of the worm, externally and internally. Locate the conspicuous clitellum, a saddle-like swelling on the dorsal surface.  The clitellum produces a mucus sheath used to surround the worms during mating and is responsible for making the cocoon within which fertilized eggs are deposited.  The anterior of the animal is more cylindrical than the flattened posterior and is the closest to the clitellum.  The ventral surface of the earthworm is usually a lighter colour than the dorsal surface.  The mouth is located on the ventral surface of the first segment while the anus is found at the end of the last segment. Find the anterior end by locating the prostomium (lip), which is a fleshy lobe that extends over the mouth. The other end of the worm’s body is the posterior end, where the anus is located.

earthworm anatomy

4. Locate the clitellum (the reproductive organ), which extends from segment 33 to segment 37. Look for the worm’s setae, which are the minute bristle-like spines located on every segment except the first and last one. Run your fingers over the ventral surface of the earthworm’s body.  You should be able to feel bristle-like setae used for locomotion

5. Refer again to the diagram of the ventral view of the worm to locate and identify the external parts of its reproductive system. Find the pair of sperm grooves that extend from the clitellum to about segment 15, where one pair of male genital pores is located. Look also for one pair of female genital pores on segment 14. There is another pair of male genital pores on about segment 26. Try to find the two pairs of openings of the seminal receptacles on segment 10.   Note: These openings are not easy to see.

 

Internal Earthworm Anatomy

 

What is the internal anatomy of an earthworm?

 

At the very front of an earthworm, you will find the pharynx. Earthworms push the pharynx from inside their mouths to grab hold of things. They pull food into their mouths and then soak it in saliva. As earthworms don’t have teeth, they have to use strong muscles called a gizzard, along with sand and soil, to grind up the food they are eating. Once the food has been fully ground up, it travels to the intestines where it is further broken down so that it can be absorbed. The majority of earthworms have five aortic arches which are like hearts and these move around their bodies. A large blood vessel runs across the top of the earthworm and this is called the dorsal blood vessel. This vessel contracts and pumps blood around to the aortic arches. There is a further blood vessel on the lower side of the earthworm which is called the ventral blood vessel. An earthworm has a very simple nervous system. A ventral nerve cord which runs the entire length of its body connects to the cerebral ganglion, which is an earthworm’s brain. Each segment is connected to the cord so that they can sense light and touch, and can move. Each segment is also wrapped in circular muscles, which contract to help the earthworm move. 

 

 

 

Continued: Dissection Procedure

 

Hint: Position your preserved earthworm dorsal side up and pin it down through the first segment and then again further back behind the clitellum.  Cut a slit in the dorsal surface near the posterior pin.  Using fine scissors extend the cut forward to the first segment.  Be careful not to cut too deep as to affect the internal organs.  Starting at the first segment, cut the septa (thin membranes) that internally divide the segments, so the skin can be laid flat.  Use additional pins to hold the integument open and expose the internal organs.  Continue to lay the skin back until you have uncovered a centimeter or so of the intestine.

6. Turn the worm dorsal side up. Using a scalpel and scissors, make a shallow incision in the dorsal side of the clitellum at segment 33. CAUTION: Scalpels and scissors are very sharp. Report any cuts to your teacher. Using the forceps and scalpel, spread the incision open, little by little. Separate each septum from the central tube using a dissecting needle, and pin down each loosened bit of skin. Continue the incision forward to segment 1.

7. Use the diagram below to locate and identify the five pairs of aortic arches, or hearts. Then find the dorsal blood vessel. Look for smaller blood vessels that branch from the dorsal blood vessel.

 

earthworm anatomy

earthworm anatomy

earthworm anatomy

earthworm anatomy

Digestive System

The earthworm is an example of a foraging herbivorous annelid, obtaining food by eating its way through the soil and extracting nutrients from the soil as it passes through the digestive tract.

Hint: Starting at the anterior end, locate the muscular pharynx (food ingestion).  This is followed by a tube-like esophagus which terminates in a crop (the wider organ) which serves as a storage stomach.  Posterior to the crop you will find the gizzard.  Gently press on the crop and gizzard to test their firmness.  While the crop is soft and thin, the gizzard is muscular (soil is ground up and churned within the gizzard).  The gizzard is followed by a long intestine in which both digestion and absorption occur.  Undigested material is voided through the anus.

8. Locate the digestive tract, which lies below the dorsal blood vessel. Refer to the diagram above to locate the pharynx, esophagus, crop, gizzard, and intestine.

earthworm anatomy

9. To find organs of the nervous system, push aside the digestive and circulatory system organs. Use the diagram below to locate the ventral nerve cord. Trace the nerve cord forward to the nerve collar, which circles the pharynx. Find one pair of ganglia under the pharynx and another pair of ganglia above the pharynx. The ganglia above the pharynx serve as the brain of the earthworm.

earthworm anatomy

earthworm anatomy

10. The worm’s excretory organs are tiny nephridia. There are two in every segment. Use the preceding diagram to locate some nephridia.

earthworm anatomy

11. Use the diagram below to locate and identify a pair of ovaries in segment 13. Look for two pairs of tiny testes in segments 10 and 11. To find these organs, you will again have to push aside some parts already dissected.

earthworm anatomy

earthworm anatomy

earthworm anatomy

12. Dispose of your materials according to the directions from your teacher in your college or university.

13. Clean up your work area and wash your hands before leaving the lab.

Earthworm worksheetEarthworm facts

BACK