Biology Keystone Review – Practice Exam
1. The diagram below represents one metabolic activity of a human.
Letters A and B are best represented by which choice below?
A. (A) is respiration, (B) is oxygen molecules
B. (A) is reproduction, (B) is hormone molecules
C. (A) is excretion, (B) is simple sugar molecules
D. (A) is digestion, (B) is amino acid molecules
2. When a person does strenuous exercise, small blood vessels (capillaries) near the
surface of the skin increase in diameter. This change allows the body to be cooled.
These statements best illustrate _____________.
3. Which sequence represents the correct order of levels of organization found in a
A. cells organelles organs organ systems tissues
B. tissues organs organ systems organelles organ systems
C. organelles cells tissues organs organ systems
D. organs organ systems cells tissues organelles
4. The instructions for the traits of an organism are coded in the arrangement of
A. glucose units in carbohydrate molecules.
B. bases in DNA in the nucleus.
C. fat molecules in the cell membrane.
D. energy-rich bonds in starch molecules.
5. Which statement is true regarding an alteration or change in DNA?
A. It is always known as a mutation.
B. It is always advantageous to an individual.
C. It is always passed on to offspring.
D. It is always detected by the process of chromatography.
6. Individual cells can be isolated from a mature plant and grown with special mixtures
of growth hormones to produce a number of genetically identical plants. This process is
known as _______.
B. meiotic division.
C. recombinant DNA technology.
D. selective breeding.
7. When a certain plant is without water for an extended period of time, guard cells close
openings in the leaves of the plant. This activity conserves water and illustrates _______.
A. cellular communication involving the action of nerve and receptor sites.
B. an increase in rate of growth due to a low concentration of water.
C. maintenance of a dynamic equilibrium through detection and response to stiumuli.
D. a response to one biotic factor in the environment.
8. The diagram below represents a section of a molecule that carries genetic information.
The pattern of numbers represents ___________.
A. a sequence of paired bases.
B. the order of proteins in genes.
C. folds of an amino acid.
D. positions of gene mutations.
9. Which statements best describe the relationship between the terms chromosomes,
genes, and nuclei?
A. Chromosomes are found on genes. Genes are found in nuclei.
B. Chromosomes are found in nuclei. Nuclei are found in genes.
C. Genes are found on chromosomes. Chromosomes are found in nuclei.
D. Genes are found in nuclei. Nuclei are found in chromosomes.
10. In a cell, information that controls the production of proteins must pass from the
nucleus to the _________.
A. cell membrane.
11. The arrows in the diagram below indicate the movement of materials into and out of
a single-celled organism.
The movements indicated by all the arrows are directly involved in ______________.
A. the maintenance of homeostasis.
B. photosynthesis, only.
C. excretion, only.
D. the digestion of minerals.
12. Certain bacteria produce a chemical that makes them resistant to penicillin. Since
these bacteria reproduce asexually, they usually produce offspring that ___________.
A. can be destroyed by penicillin.
B. mutate into another species.
C. are genetically different from their parents.
D. survive exposure to penicillin.
13. A sudden change in the DNA of a chromosome can usually be passed on to future
generations if the change occurs in a __________.
A. skin cell.
B. liver cell.
C. sex cell.
D. brain cell.
14. A change in the order of DNA bases that code for a respiratory protein will most
likely cause ___________.
A. the production of a starch that has a similar function.
B. the digestion of the altered gene by enzymes.
C. a change in the sequence of amino acids determined by the gene.
D. the release of antibodies by certain cells to correct the error.
15. The data in the graph below shows evidence of disease in the human body.
A disruption in dynamic equilibrium is indicated by the temperature change between
A. A & C
B. B & C
C. C & D
D. E & F
16. The diagram below represents some stages of early embryonic development.
Which process is represented by the arrows in the diagram?
17. Which words best complete the lettered blanks in the two sentences below?
“Organic compounds, such as proteins and starches, are too ___1___ to diffuse into
cells. Proteins are digested into ____2___ , and starches are digested into ___3___.”
A. (1) large, (2) simple sugars, (3) amino acids
B. (1) small, (2) simple sugars, (3) amino acids
C. (1) large, (2) amino acids, (3) simple sugars
D. (1) small, (2) amino acids, (3) simple sugars
18. Which statement concerning simple sugars and amino acids is correct?
A. They are both wastes resulting from protein synthesis.
B. They are both building blocks of starch.
C. They are both needed for the synthesis of larger molecules.
D. They are both stored as fat molecules in the liver.
19. The diagram below represents two single-celled organisms.
These organisms carry out the activities needed to maintain homeostasis by using
specialized internal _______.
20. The sequence of subunits in a protein is most directly dependent on the __________.
A. region in the cell where enzymes are produced.
B. DNA in the chromosomes in a cell.
C. type of cell in which starch is found.
D. kinds of materials in the cell membrane.
21. The genetic code of a DNA molecule is determined by a specific sequence of _____.
A. ATP molecules
B. sugar molecules
C. chemical bonds
D. molecular bases
22. The cells that make up the skin of an individual have some functions different from
the cells that make up the liver because __________.
A. all cells have a common ancestor.
B. different cells have different genetic material.
C. environment and past history have no influence on cell function.
D. different parts of genetic instructions are used in different types of cells.
23. A mutation occurs in a cell. Which sequence best represents the correct order of the
events involved for this mutation to affect the traits expressed by this cell?
A. A change in the sequence of DNA bases joining amino acids in sequence
appearance of characteristic
B. joining amino acids in sequence a change in the sequence of DNA bases
appearance of characteristic
C. appearance of characteristic joining amino acids in sequence a change in the
sequence of DNA bases
D. a change in the sequence of DNA bases appearance of characteristic joining
amino acids in sequence
24. Some human body cells are shown in the diagrams below.
These groups of cells represent different ____________.
A. tissues in which similar cells function together.
B. organs that help to carry out a specific life activity.
C. systems that are responsible for a specific life activity.
D. organelles that carry out different functions.
25. Which statement is true of both mitosis and meiosis?
A. Both are involved in asexual reproduction.
B. Both occur only in reproductive cells.
C. The number of chromosomes is reduced by half.
D. DNA replication occurs before the division of the nucleus.
26. A cell resulting from the fertilization of an egg begins to divide. Two cells are
formed that normally remain attached and could develop into a new individual. If the
two cells become separated, which statement describes what would most likely occur?
A. The cells would each have all of the needed genetic information, and both could
B. The cells would each have only one-half of the needed genetic information, so both
C. One cell would have all of the needed genetic information and would survive, but the
other would have none of the needed genetic information and would die.
D. Each cell would have some of the needed genetic information, but would be unable to
share it, so both would die.
27. Down syndrome is a genetic disorder caused by the presence of an extra
chromosome in the body cells of humans. This extra chromosome occurs in gametes as a
result of _________.
A. an error in the process of cloning.
B. an error in meiotic cell division.
C. a gene mutation.
D. replication of a single chromosome during mitosis.
28. Based on their analysis of the differences in amino acid sequences of one kind of
protein, scientists prepared the evolutionary tree shown below.
According to the diagram, the DNA of which pair of organisms would show the greatest
A. penguin and turtle
B. horse and donkey
C. snake and tuna
D. turtle and rabbit
29. A stable pond ecosystem would not contain ________.
A. materials being cycled.
D. more consumers than producers.
30. Certain poisons are toxic to organisms because they interfere with the function of
enzymes in mitochondria. This results directly in the inability of the cell to ________.
A. store information.
B. build proteins.
C. release energy from nutrients.
D. dispose of metabolic wastes.
31. The diagram below represents the synthesis of a complex molecule in an organism.
Which choice below correctly identifies the building blocks and proteins?
A. starch molecules glucose
B. amino acid molecules part of protein
C. sugar molecules ATP
D. DNA molecules part of starch
32. Which diagram best represents the relative locations of the structures in the list
A – Chromosome B – Nucleus C – Cell D – Gene
A. Diagram 1
B. Diagram 2
C. Diagram 3
D. Diagram 4
33. Certain insects resemble the bark of trees on which they live. Which statement
provides a possible biological explanation for this resemblance?
A. The insects needed camouflage so they developed protective coloration.
B. Natural selection played a role in the development of this protective coloration.
C. The lack of mutations resulted in the protective coloration.
D. The trees caused mutations in the insects that resulted in protective coloration.
34. In what way are photosynthesis and cellular respiration similar?
A. They both occur in chloroplasts.
B. They both require sunlight.
C. The both involve organic and inorganic molecules.
D. The both require oxygen and produce carbon dioxide.
35. Some cells involved in the process of reproduction are represented in the diagram
The process of meiosis formed __________.
A. cell 1, only.
B. cells 1 and 2.
C. cell 3, only.
D. cells 2 and 3.
36. The diagram below represents an event that occurs in the blood.
Which statement best describes this event?
A. Cell A is a white blood cell releasing antigens to destroy bacteria.
B. Cell A is a cancer cell produced by the immune system and it is helping to prevent
C. Cell A is a white blood cell engulfing disease-causing organisms.
D. Cell A is protecting bacteria so they can reproduce without being destroyed by
37. In an ecosystem, the growth and survival of organisms is dependent on the
availability of the energy from the sun. This energy is available to organisms in the
ecosystem because ____________.
A. producers have the ability to store energy from light in organic molecules.
B. consumers have the ability to transfer chemical energy stored in bonds to plants.
C. all organisms in a food web have the ability to use light energy.
D. all organisms in a food web feed on autotrophs.
38. A food chain is represented below.
Grass Cricket Frog Owl
This food chain contains __________.
A. 4 consumers and no producers.
B. 1 predator, 1 parasite, and 2 producers.
C. 2 carnivores and 2 herbivores.
D. 2 predators, 1 herbivore, and 1 producer.
39. A major reason that humans can have such a significant impact on an ecological
community is that humans _____________.
A. can modify their environment through technology.
B. reproduce faster than most other species.
C. are able to increase the amount of finite resources available.
D. remove large amounts of carbon dioxide from the air.
40. The diagram below shows some of the steps in protein synthesis.
The section of DNA being used to make the strand of mRNA is known as a _________.
41. An energy pyramid is shown below.
Which graph best represents the relative energy content of the levels of this pyramid?
A. B. C. D.
42. The diagram below represents four different species of bacteria.
Which statement is correct concerning the chances of survival for these species if there is
a change in the environment?
A. Species A has the best chance of survival because it has the most genetic diversity.
B. Species C has the best chance of survival because it has no gene mutations.
C. Neither species B nor species D will survive because they compete for the same
D. None of the species will survive because bacteria reproduce asexually.
43. On which day did the population represented in the graph below reach the carrying
capacity of the ecosystem?
A. Day 11
B. Day 8
C. Day 3
4. Day 5
44. The diagram below represents a yeast cell that is in the process of budding, a form of
Which statement describes the outcome of this process?
A. The bud will develop into a zygote.
B. The two cells that result will each contain half the species number of chromosomes.
C. The two cells that result will have identical DNA.
D. The bud will start to divide by the process of meiotic cell division.
45. Even though each body cell in an individual contains the same DNA, the functions of
muscle cells and liver cells are not the same because ______________.
A. mutations usually occur in genes when muscle cells divide.
B. liver tissue develops before muscle tissue.
C. liver cells produce more oxygen than muscle cells.
D. liver cells use different genes than muscle cells.
46. Which part of a molecule provides energy for life processes?
A. carbon atoms
B. oxygen atoms
C. chemical bonds
D. inorganic nitrogen
47. Energy from organic molecules can be stored in ATP molecules as a direct result of
the process of ________.
A. cellular respiration.
B. cellular reproduction.
48. The graph below represents the amount of available energy at successive nutrition
levels in a particular food web.
The Xs in the diagram represent the amount of energy that was most likely __________.
A. changed into inorganic compounds.
B. retained indefinitely by the herbivores.
C. recycled back to the producers.
D. lost as heat to the environment.
49. Which characteristic is shared by all prokaryotes and eukaryotes?
A. Ability to store hereditary information
B. Use of organelles to control cell processes
C. Use of cellular respiration for energy release
D. Ability to move in response to environmental stimuli
50. Living organisms can be classified as prokaryotes or eukaryotes. Which two
structures are common to both prokaryotic and eukaryotic cells?
A. Cell wall and nucleus
B. Cell wall and chloroplast
C. Plasma membrane and nucleus
D. Plasma membrane and cytoplasm
51. Which statement best describes an effect of the low density of frozen water in a lake?
A. When water freezes, it contracts, decreasing the water level in a lake
B. Water in a lake freezes from the bottom up, killing most aquatic organisms
C. When water in a lake freezes, it floats, providing insulation for organisms below
D. Water removes thermal energy from the land around a lake, causing the lake to freeze
52. Which statement correctly describes how carbon’s ability to form four bonds makes
it uniquely suited to form macromolecules?
A. It forms short, simple carbon chains.
B. It forms large, complex, diverse molecules.
C. It forms covalent bonds with other carbon atoms.
D. It forms covalent bonds that can exist in a single plane.
53. Substance A is converted to substance B in a metabolic reaction. Which statement
best describes the role of an enzyme during this reaction?
A. It adjusts the pH of the reaction medium.
B. It provides energy to carry out the reaction.
C. It dissolves substance A in the reaction medium.
D. It speeds up the reaction without being consumed.
54. A scientist observes that, when the pH of the environment surrounding an enzyme is
changed, the rate the enzyme catalyzes a reaction greatly decreases. Which statement
best describes how a change in pH can affect an enzyme?
A. A pH change can cause the enzyme to change its shape.
B. A pH change can remove energy necessary to activate an enzyme.
C. A pH change can add new molecules to the structure of the enzyme.
D. A pH change can cause an enzyme to react with a different substrate.
55. Using a microscope, a student observes a small, green organelle in a plant cell.
Which energy transformation most likely occurs first within the observed organelle?
A. ATP to light
B. Light to chemical
C. Heat to electrical
D. Chemical to chemical
56. Photosynthesis and cellular respiration are two major processes of carbon cycling in
living organisms. Which statement correctly describes one similarity between
photosynthesis and cellular respiration?
A. Both occur in animal and plant cells.
B. Both include reactions that transform energy.
C. Both convert light energy into chemical energy.
D. Both synthesize organic molecules as end products.
57. Carbon dioxide and oxygen are molecules that can move freely across a plasma
membrane. What determines the direction that carbon dioxide and oxygen molecules
A. Orientation of cholesterol in the plasma membrane.
B. Concentration gradient across the plasma membrane.
C. Configuration of phospholipids in the plasma membrane.
D. Location of receptors on the surface of the plasma membrane.
58. The rough endoplasmic reticulum and Golgi apparatus work together in eukaryotic
cells. What is one way that the rough endoplasmic reticulum assists the Golgi apparatus?
A. It assembles nucleic acids from monomers.
B. It breaks down old, damaged macromolecules.
C. It packages new protein molecules into vesicles.
D. It determines which protein molecules to synthesize.
59. Which statement best describes the phase of the cell cycle shown in the figure
A. The cell is in prophase of mitosis because the number of chromosomes has doubled.
B. The cell is in prophase I of meiosis because the number of chromosomes has doubled.
C. The cell is in telophase of mitosis because the cell is separating and contains two
copies of each chromosome.
D. The cell is in telophase of meiosis because the cell is separating and contains two
copies of each chromosome.
60. Which process helps to preserve the genetic information stored in DNA during DNA
A. The replacement of nitrogen base thymine with uracil
B. Enzymes quickly linking nitrogen bases with hydrogen bonds
C. The synthesis of unique sugar and phosphate molecules for each nucleotide
D. Nucleotides lining up along the template strand according to base pairing rules
61. Use the table below to answer this question. Blood type is inherited through multiple
alleles, including IA, IB, and i. A child has type A blood. If the father has type AB
blood, what are all the possible phenotypes of the mother?
A. Phenotypes O or A
B. Phenotypes A or AB
C. Phenotypes A, B, or AB
D. Phenotypes O, A, B, AB
62. Which type of change in chromosome composition is illustrated in the diagram
63. The endoplasmic reticulum is a network of membranes within the cell, and it is often
classified as rough or smooth, depending on whether there are ribosomes on its surface.
Which statement best describes the role of the rough endoplasmic reticulum in the cell?
A. It stores all proteins for later use.
B. It provides an attachment site for larger organelles?
C. It aids in the production of membranes and secretory proteins.
D. It stores amino acids required for the production of all proteins.
64. The graphs below illustrate change in a lizard population over time. Which process
most likely led to the change in the lizard population?
A. Natural selection acting on a harmful trait.
B. Natural selection acting on a beneficial trait.
C. Natural selection acting on a dominant trait.
D. Natural selection acting on a recessive trait.
65. In North America, the eastern spotted skunk mates in late winter, and the western
spotted skunk mates in late summer. Even though their geographic ranges overlap, the
species do not mate with each other. What most likely prevents these two species from
A. Habitat isolation
B. Gametic isolation
C. Geographic isolation
D. Reproductive isolation
66. A mutation occurs in the genes that code for coat color in deer. Which change will
most likely result from this mutation?
A. A change in the selection pressures acting on coat color
B. A change in the coat-color genes of deer predator species
C. An increase in coat-color diversity in the population
D. An increase in the number of genes for coat color in the population
67.The skeletons of mammalian forelimbs represent variations of a structure that was
present in their common ancestor. What most likely caused the variation in the forelimbs
A. Changes in muscle structure
B. Changes in the genetic codes
C. Trait formation due to behaviors
D. Development of vestigial structures
68. A group of students measured a ten-square-meter section of a pond ecosystem and
recorded observations. Using the table below, which statement is a testable hypothesis?
A. The frogs living in the pond represent a population.
B. Water is an abiotic component in the pond ecosystem.
C. If the fish are given more food, then they will be happier.
D. If the frogs are startled, then they will jump into the water.
69. Use the list below to answer the question.
A student wrote several observations in a field notebook. Which term best classifies all
of the student’s observations?
B. Food chain
70. A researcher observing an ecosystem describes the amount of sunlight, precipitation,
and type of soil present. Which factor is the researcher most likely describing?
A. Biotic factors in a forest
B. Biotic factors in a tundra
C. Abiotic factors in a prairie
D. Abiotic factors in an ocean
71. A species of snapping turtle has a tongue that resembles a worm. The tongue is used
to attract small fish. Which best describes the interaction between the fish and the
72. Which statement correctly describes how nitrogen in the soil returns to the
A. Soil bacteria convert nitrates into nitrogen gas
B. Decomposers directly convert ammonium into nitrogen gas
C. Plants assimilate nitrites and convert them into nitrogen gas
D. Nitrogen-fixing bacteria in plant roots convert nitrates into nitrogen gas
73. One of the three basic structures common to almost all cells, prokaryotic or
eukaryotic, is the
A. Cell wall
C. Cell membrane
74. When the cell manufactures a protein that will be excreted from the cell, what role
does the Golgi apparatus play in the protein’s processing?
A. The Golgi apparatus receives the protein from the endoplasmic reticulum, modifies it,
and packages it into vesicles that bud off and fuse with the cell membrane.
B. The Golgi apparatus receives the protein from the endoplasmic reticulum, modifies it,
and packages it into vesicles that bud off and return to the endoplasmic reticulum.
C. The Golgi apparatus receives the protein from the nucleus, modifies it, and packages
it into vesicles that bud off and fuse with the cell membrane.
D. The Golgi apparatus receives the protein from the nucleus, modifies it, and packages
it into vesicles that bud off and return to the nucleus.
75. Oceans and lakes absorb large amounts of heat yet only have small changes in
temperature. Organisms living in these bodies of water, therefore, are protected from
drastic temperature changes. Which property of water accounts for these observations?
A. Water’s cohesive attraction to other water molecules
B. Water’s adhesive attraction to the shore line
C. Water’s freezing point
D. Water’s high specific heat
76. In Shorthorn cattle, coat color exhibits co-dominance. Red is represented by the
genotype CRCR. Roan is an intermixing of colors and is represented by the genotype
CRCW. White is represented by the genotype CWCW. If a red Shorthorn and a roan
Shorthorn were crossed, what are the chances of getting a red Shorthorn in the offspring?
77. In a type of flower called Four O’clocks, flower color exhibits incomplete
dominance. RR produces red flowers, rr produces white flowers, and Rr produces pink
flowers. In a cross, a red-flowered plant is mated with a white-flowered plant. If the F1
offspring are self-pollinated, what phenotypes are expected in the F2 generation?
A. pink and white
B. red, pink, and white
D. red and white
78. Which of the following is NOT a way that the founder effect can lead to changes in a
A. The population must be very large.
B. The population must have no mutations.
C. The population must undergo random mating.
D. There must be large amounts of movement into and out of the population.
79. Which of the following statements is an inference that can be made about the data in
the table below?
Year Frequency of allele B, Frequency of allele b,
black coat color brown coat color
1910 0.81 0.19
1930 0.49 0.51
1950 0.25 0.75
1970 0.10 0.90
A. The frequency of allele B steadily decreased over time while the frequency of allele b
steadily increased over time.
B. The frequency of allele b steadily decreased over time while the frequency of allele B
steadily increased over time.
C. Over time, predators began to consume more black-coated animals.
D. Over time, predators began to consume more brown-coated animals.
80. Which of the following describes the major levels of organization studied by
ecologist, from smallest to largest?
A. Biosphere, biome, ecosystem, community, population, organism
B. Biosphere, ecosystem, biome, community, population, organism
C. Organism, population, ecosystem, community, biome, biosphere
D. Organism, population, community, ecosystem, biome, biosphere
81. Which of the following is NOT a way that carbon is returned to the atmosphere?
A. Burning of fossil fuels
B. Released by organisms during cellular respiration
C. Decomposers breaking down bodies of dead organisms
D. Evaporates from the oceans and other large bodies of water