AP Biology Mid-Term Exam

Assuming these age-structure diagrams describe human populations, which population is likely to experience zero population growth (ZPG)?

A. I
B. I and II
C. II
D. III
E. II and III

Which population is in the process of decreasing?

A. III
B. II and III
C. II
D. I and II
E. I

Assuming these age-structure diagrams describe human populations, in which population is unemployment likely to be most severe in the future?

A. It is not possible to infer anything about future social conditions from age-structure diagrams.
B. No differences in the magnitude of future unemployment would be expected among these populations.
C. I
D. II
E. III

Which population appears to be stable?

A. II and III
B. I and II
C. I
D. II
E. III

The oak tree pathogen Phytophthora ramorum migrated 650 km in ten years. West Nile virus spread from New York to 46 others states in five years. The difference in the rate of spread is probably related to

A. innate resistance.
B. the mobility of their hosts.
C. how lethal each pathogen is.
D. the fact that viruses are very small.
E. none of the above

A species of fish is found to require a certain water temperature, a particular oxygen content of the water, a particular depth, and a rocky substrate on the bottom to thrive. These requirements are part of its

A. resource partition.
B. home base.
C. dimensional profile.
D. prime habitat.
E. ecological niche.

Extinction is a natural phenomenon. It is estimated that 99% of all species that ever lived are now extinct. Why then do we say that we are now in a biodiversity crisis?

A. Most biodiversity hot spots have been destroyed by recent ecological disasters.
B. Humans have greater medical needs than at any other time in history, and many potential medicinal compounds are being lost as plant species become extinct.
C. Humans are ethically responsible for protecting endangered species.
D. Scientists have finally identified most of the species on Earth and are thus able to quantify the number of species becoming extinct.
E. The current rate of extinction is as much as 1,000 times higher than at any other time in the last 100,000 years.

Prairie dogs once covered the expanses of the Great Plains. Their grazing made the grass more nutritious for the huge herds of bison, and a variety of snakes, raptors, and mammals preyed on the rodents. In fact, the black-footed ferret (now endangered) specialized in prairie dog predation. Today, growing neighborhoods have covered many prairie dog towns. Which of the following statements about prairie dogs is not true?

A. Their realized niche has diminished.
B. They are reasonably considered a keystone species.
C. They are commensals with bison.
D. Their fundamental niche remains unaltered.
E. Their fundamental niche has diminished.

Use the terms below to answer the following questions. Match the term that best fits each of the following descriptions of behavior. Each term may be used once, more than once, or not at all.

A. imprinting
B. habituation
C. classical conditioning
D. sign stimulus
E. operant conditioning

Male insects attempt to mate with orchids but eventually stop responding to them.

a. A
b. B
c. C
d. D
e. E

Use the terms below to answer the following questions. Match the term that best fits each of the following descriptions of behavior. Each term may be used once, more than once, or not at all.

A. imprinting
B. habituation
C. operant conditioning
D. sign stimulus
E. classical conditioning

Sparrows are receptive to learning songs only during a sensitive period.

a. A
b. B
c. C
d. D
e. E

Use the terms below to answer the following questions. Match the term that best fits each of the following descriptions of behavior. Each term may be used once, more than once, or not at all.

A. habituation
B. classical conditioning
C. imprinting
D. operant conditioning
E. sign stimulus

A guinea pig loves the lettuce kept in the refrigerator and squeals each time the refrigerator door opens.

a. A
b. B
c. C
d. D
e. E

Use the terms below to answer the following questions. Match the term that best fits each of the following descriptions of behavior. Each term may be used once, more than once, or not at all.

A. sign stimulus
B. classical conditioning
C. imprinting
D. habituation
E. operant conditioning

A stickleback fish will attack a fish model as long as the model has red coloring.

a. A
b. B
c. C
d. D
e. E

Use the terms below to answer the following questions. Match the term that best fits each of the following descriptions of behavior. Each term may be used once, more than once, or not at all.

A. habituation
B. imprinting
C. sign stimulus
D. classical conditioning
E. operant conditioning

Parental protective behavior in turkeys is triggered by the cheeping sound of young chicks.

a. A
b. B
c. C
d. D
e. E

The species richness of a community refers to the

A. energy content of all species
B. number of different species.
C. total number of all organisms.
D. relative numbers of individuals in each species.
E. number of food chains.

Which curve best describes survivorship in humans who live in developed nations?

A. C
B. D
C. B
D. A
E. E

Which curve best describes survivorship that is independent of age?

A. C
B. E
C. B
D. D
E. A

Which curve best describes survivorship in oysters?

A. E
B. B
C. A
D. C
E. D

Which curve best describes survivorship in squirrels?

A. D
B. C
C. E
D. A
E. B

Which of the following interactions can correctly be labeled coevolution?

A. the tendency of coyotes to respond to human habitat encroachment by including pet dogs and cats in their diets
B. a genetic change in a virus that allows it to exploit a new host, which responds to virus-imposed selection by changing its genetically controlled habitat preferences
C. a genetic change in foxes that allows them to tolerate human presence (and food)
D. the adaptation of cockroaches to human habitation
E. the ability of rats to survive in a variety of novel environments

Elephants are not the most common species in African grasslands. The grasslands contain scattered woody plants, but they are kept in check by the uprooting activities of the elephants. Take away the elephants, and the grasslands convert to forests or to shrublands. The newly growing forests support fewer species than the previous grasslands. Elephants can be defined as what type of species in this community?

A. dominant
B. keystone
C. redundant
D. dominant and keystone
E. none of the above

The presence of all of the following tend to increase species diversity except

A. keystone predators.
B. migration of populations.
C. competitive exclusion.
D. patchy environments.
E. moderate disturbances.

Which of the following is an example of cryptic coloration?

A. a "walking stick" insect that resembles a twig
B. bands on a coral snake
C. markings of a viceroy butterfly
D. brown color of tree bark
E. colors of an insect-pollinated flower

Sow bugs become more active in dry areas and less active in humid areas. This is an example of

A. kinesis.
B. taxis.
C. tropism.
D. net reflex.
E. cognition

Use the information below to answer the following questions: When a female cat comes into heat, she urinates more frequently and in a large number of places. Male cats from the neighborhood congregate near urine deposits and fight with each other.

Which of the following is a proximate cause of this behavior of increased urination?

A. Female cats that did this in the past attracted more males.
B. It is a result of hormonal changes associated with her reproductive cycle.
C. The female cat learned the behavior from observing other cats.
D. It announces to the males that she is in heat.
E. All of the above are ultimate causes of behavior.

When a female cat comes into heat, she urinates more frequently and in a large number of places. Male cats from the neighborhood congregate near urine deposits and fight with each other.

Which of the following would be an ultimate cause of the male cats' response to the female's urinating behavior?

A. The odor serves as a releaser for the instinctive behavior of the males.
B. Male cats respond to the odor because it is a means of locating females in heat.
C. The males have learned to recognize the specific odor of the urine of a female in heat.
D. By smelling the odor, various neurons in the males' brains were stimulated.
E. Male cats' hormones are triggered by the odor released by the female.

Which of the following statements is consistent with the competitive exclusion principle?

A. The density of one competing species will have a positive impact on the population growth of the other competing species.
B. Even a slight reproductive advantage will eventually lead to the elimination of inferior species.
C. Bird species generally do not compete for nesting sites.
D. Evolution tends to increase competition between related species.
E. Two species with the same fundamental niche will exclude other competing species.

Every morning at the same time, John went into the den to feed his new tropical fish. After a few weeks John noticed that the fish would swim to the top of the tank as soon as he would enter the room. This is a good example of

A. classical conditioning.
B. habituation.
C. imprinting.
D. maturation.
E. operant conditioning.

How is it that the open ocean produces the highest net primary productivity of Earth's ecosystems, yet net primary productivity per square meter is relatively low?

A. It contains greater concentrations of nutrients.
B. It has the greatest total area.
C. It contains more species of organisms.
D. It receives a greater amount of solar energy per unit area.
E. Its producers are generally much smaller than its consumers.

Which of the following is an example of aposematic coloration?

A. eye color in humans
B. colors of an insect-pollinated flower
C. a katydid whose wings look like a dead leaf
D. stripes of a skunk
E. green color of a plant

Which of the following is a density-independent factor limiting human population growth?

A. earthquakes
B. plagues
C. famines
D. social pressure for birth control
E. pollution

How is habitat fragmentation related to extinction?

A. Animals are forced out of habitat fragments.
B. Less carbon dioxide is absorbed by plants.
C. More soil is subject to erosion.
D. Populations of organisms in fragments are smaller and, thus, more susceptible to extinction.
E. Fragments generate silt that negatively affects drainages.

Which of the following statements best describes the interaction between fire and ecosystems?

A. The prevention of forest fires has allowed more productive and stable plant communities to develop.
B. The chance of fire in a given ecosystem is highly predictable over the short term.
C. Chaparral communities have evolved to the extent that they rarely burn.
D. Many kinds of plants and plant communities have adapted to frequent fires.
E. Fire is unnatural in ecosystems and should be prevented.

Which of the following statements about energy flow is incorrect?

A. About 90% of the energy at one trophic level does not appear at the next.
B. Only about one-thousandth of the chemical energy fixed by photosynthesis reaches a tertiary-level consumer.
C. Secondary productivity declines with each trophic level.
D. Eating meat is probably the most economical way of acquiring the energy of photosynthetic productivity.
E. Only net primary productivity is available to consumers.

One way to understand how early environment influences differing behaviors in similar species is through an experimental technique known as "cross fostering." Suppose that the curly-whiskered mud rat differs from the bald mud rat in several ways, for example curly-whiskered rats are much more aggressive. How would you set up a cross-fostering experiment to determine if environment plays a role in this mud rat's aggression?

A. You would see if curly-whiskered mud rats bred true for aggression.
B. You would remove the offspring of curly-whiskered mud rats and bald mud rats from their parents and raise them in the same environment.
C. You would cross curly-whiskered mud rats and bald mud rats and hand-rear the offspring.
D. You would place newborn curly-whiskered mud rats with bald mud rat parents, newborn bald mud rats with curly-whiskered mud rat parents, and let some mud rats of both species be raised by their own species. Then compare the outcomes.
E. None of these schemes describes cross fostering.

The energetic hypothesis and dynamic stability hypothesis are explanations to account for

A. resource partitioning.
B. plant defenses against herbivores.
C. the length of food chains.
D. the evolution of mutualism.
E. the competitive exclusion principle.

According to the U.S. Endangered Species Act (ESA), the difference between an endangered species and a threatened one is that

A. endangered species are mainly tropical.
B. an endangered species is closer to extinction.
C. There is no real difference.
D. a threatened species is closer to extinction.
E. threatened species are endangered species outside the U.S. borders.

Which of the following terms includes all of the others?

A. genetic diversity
B. biodiversity
C. ecosystem diversity
D. species diversity
E. species richness

Which of the following is an example of Batesian mimicry?

A. a snapping turtle that uses its tongue to mimic a worm, thus attracting fish
B. an insect that resembles a twig
C. a butterfly that resembles a leaf
D. a nonvenomous snake that looks like a venomous snake
E. a fawn with fur coloring that camouflages it in the forest environment

The entire box shown in the figure below represents the niche of species A. Species A is biologically constrained from the striped area of its niche by species B. This is an example of

A. dynamic stability.
B. facilitation.
C. commensalism.
D. competitive exclusion.
E. secondary succession.

Resource partitioning is best described by which of the following statements?

A. Species diversity is maintained by switching between prey species.
B. Slight variations in niche allow similar species to coexist.
C. Two species can coevolve and share the same niche.
D. A climax community is reached when no new niches are available.
E. Competitive exclusion results in the success of the superior species.

Based on your knowledge of the polarity of water molecules, the solute molecule is most likely

A. without charge.
B. positively charged.
C. negatively charged.
D. nonpolar.
E. hydrophobic.

Which of the following statements about ecology is incorrect?

A. Ecologists may study populations and communities of organisms.
B. Ecological studies may involve the use of models and computers.
C. Ecology spans increasingly comprehensive levels of organization, from individuals to ecosystems.
D. Ecology is the study of the interactions between biotic and abiotic aspects of the environment.
E. Ecology is a discipline that is independent from natural selection and evolutionary history.

Which of the following molecules are structural isomers?

A. 14 and 15
B. 1 and 4
C. 12 and 13
D. 5 and 14
E. 6 and 12

Which of the following molecules is an amino acid with a hydrophobic R group or side chain?

A. 7
B. 8
C. 5
D. 3
E. 12

Which of the following molecules is a saturated fatty acid?

a. 1
b. 5
c. 6
d. 8 e. 9

Which of the following molecules has (have) a functional group that frequently is involved in maintaining the tertiary structure of a protein?

A. 9 and 11
B. 3
C. 9
D. 2
E. 11

Which of the following combinations could be linked together to form a nucleotide?

A. 12, 14, and 15
B. 3, 7, and 8
C. 1, 2, and 11
D. 11, 12, and 13
E. 5, 9, and 10

Which of the following molecules contain(s) an aldehyde type of carbonyl functional group?

A. 1 and 4
B. 4
C. 1
D. 10
E. 8

Which of the following molecules consists of a hydrophilic "head" region and a hydrophobic "tail" region?
A. 11
B. 2
C. 9
D. 7
E. 5

The two molecules shown in the following figure are best described as

A. radioactive isotopes.
B. structural isomers.
C. enantiomers.
D. nonisotopic isomers.
E. geometric isomers.

Atoms whose outer electron shells contain eight electrons tend to

A. form covalent bonds in aqueous solutions.
B. be stable and chemically nonreactive, or inert.
C. be isotopes and very radioactive.
D. form ionic bonds in aqueous solutions.
E. be unstable and chemically very reactive.

Which bond is closest to the N-terminus of the molecule?

A. Bond C
B. Bond B
C. Bond D
D. Bond E
E. Bond A

Which bond is closest to the C-terminus of the molecule?

A. Bond B
B. Bond A
C. Bond D
D. Bond C
E. Bond E

At which bond would water need to be added to achieve hydrolysis of the peptide, back to its component amino acid?

A. Bond D
B. Bond C
C. Bond B
D. Bond E
E. Bond A

The chemical reaction illustrated in the figure below results in the formation of a (an)

A. ionic bond.
B. peptide bond.
C. glycosidic linkage.
D. ester linkage.
E. phosphodiester linkage.

A chemist wishes to make an organic molecule less acidic. Which of the following functional groups should be added to the molecule in order to do so?

A. carboxyl
B. sulfhydryl
C. hydroxyl
D. amino
E. phosphate

What is the name of the functional group shown in the following figure?
A. carboxyl
B. aldehyde
C. ketone
D. carbonyl
E. hydroxyl

Polymers of polysaccharides, fats, and proteins are all synthesized from monomers by which process?

A. the removal of water (dehydration reactions)
B. the formation of disulfide bridges between monomers
C. ionic bonding of the monomers
D. connecting monosaccharides together (condensation reactions)
E. the addition of water to each monomer (hydrolysis)

One of the buffers that contribute to pH stability in human blood is carbonic acid (H2CO3) Carbonic acid is a weak acid that dissociates into a bicarbonate ion (HCO3-) and a hydrogen ion (H+) Thus, H2CO3 HCO3- + H+ If the pH of the blood drops, one would expect

A. the concentration of bicarbonate ion (HCO3-) to increase.
B. the HCO3- to act as an acid and remove excess H+ with the formation of H2CO3.
C. the HCO3- to act as a base and remove excess H+ with the formation of H2CO3.
D. a decrease in the concentration of H2CO3 and an increase in the concentration of HCO3-.
E. the concentration of hydroxide ion (OH-) to increase.

At which level of protein structure are interactions between the side chains (R groups. most important?

A. primary
B. secondary
C. tertiary
D. quaternary
E. all of the above

One of the buffers that contribute to pH stability in human blood is carbonic acid H2CO3. Carbonic acid is a weak acid that when placed in an aqueous solution dissociates into a bicarbonate ion (HCO3-) and a hydrogen ion (H+) Thus, H2CO3 HCO3- + H+ If the pH of the blood increases, one would expect

A. a decrease in the concentration of H2CO3 and an increase in the concentration of H2O.
B. an increase in the concentration of H2CO3 and a decrease in the concentration of H2O.
C. a decrease in the concentration of HCO3- and an increase in the concentration of H2O.
D. an increase in the concentration of HCO3- and a decrease in the concentration of H2O.
E. a decrease in the concentration of HCO3- and an increase in the concentration of both H2CO3and H2O.

What is the reason why hydrocarbons are not soluble in water?

A. They exhibit considerable molecular complexity and diversity.
B. The majority of their bonds are polar covalent carbon to hydrogen linkages.
C. The majority of their bonds are nonpolar covalent carbon-to-hydrogen linkages.
D. They are lighter than water.
E. They are hydrophilic.

The tertiary structure of a protein is the

A. order in which amino acids are joined in a polypeptide chain.
B. unique three-dimensional shape of the fully folded polypeptide.
C. organization of a polypeptide chain into an á helix or â pleated sheet.
D. bonding together of several polypeptide chains by weak bonds.
E. overall protein structure resulting from the aggregation of two or more polypeptide subunits.

Which of the following terms includes all of the others?

A. species richness
B. genetic diversity
C. ecosystem diversity
D. species diversity
E. biodiversity

Which of the following is possible due to the high surface tension of water?

A. A water strider can walk across the surface of a small pond.
B. Organisms resist temperature changes, although they give off heat due to chemical reactions.
C. The pH of water remains exactly neutral.
D. Water can act as a solvent.
E. Lakes don't freeze solid in winter, despite low temperatures.

Which of the following is an example of hydrolysis?

A. the synthesis of a nucleotide from a phosphate, a pentose sugar, and a nitrogenous base with the production of a molecule of water
B. the reaction of a fat, forming glycerol and fatty acids with the utilization of water
C. the reaction of a fat, forming glycerol and fatty acids with the release of water
D. the reaction of two monosaccharides, forming a disaccharide with the release of water
E. the synthesis of two amino acids, forming a peptide with the release of water

What is the fundamental difference between matter and energy?

A. Energy is cycled through ecosystems; matter is not.
B. Matter is used in ecosystems; energy is not
C. Matter is cycled through ecosystems; energy is not.
D. Matter can be converted into energy; energy cannot be converted into matter.
E. Energy can be converted into matter; matter cannot be converted into energy.

Observe the structures of glucose and fructose. These two molecules differ in the

A. number of carbon, hydrogen, and oxygen atoms.
B. answers A, B, and C
C. types of carbon, hydrogen, and oxygen atoms.
D. arrangement of carbon, hydrogen, and oxygen atoms.
E. number of oxygen atoms joined to carbon atoms by double covalent bonds.

Observe the structures of glucose and fructose. These two molecules are

A. nonisotopic isomers.
B. enantiomers.
C. structural isomers.
D. geometric isotopes.
E. geometric isomers.

The main decomposers in an ecosystem are

A. fungi.
B. plants.
C. insects.
D. prokaryotes.
E. both A and D

Important abiotic factors in ecosystems include which of the following?

A. water
B. temperature
C. A and C only
D. A, B, and C
E. wind

A cow's herbivorous diet indicates that it is a(n)

A. decomposer.
B. primary consumer.
C. autotroph.
D. producer.
E. secondary consumer.

Which of the following abiotic factors has the greatest influence on the metabolic rates of plants and animals?
A. temperature
B. disturbances
C. rocks and soil
D. water
E. wind

Which of the following terms encompasses all of the others?

A. heterotrophs
B. secondary consumers
C. primary consumers
D. carnivores
E. herbivores

What is the structure shown in the figure below?

A. steroid molecule
B. cellulose molecule
C. starch molecule
D. protein molecule
E. phospholipid molecule

Which of the following contains nitrogen in addition to carbon, oxygen, and hydrogen?

A. an amino acid such as glycine
B. a hydrocarbon such as benzene
C. an alcohol such as ethanol
D. a steroid such as testosterone
E. a monosaccharide such as glucose

To recycle nutrients, the minimum an ecosystem must have is

A. producers.
B. producers, primary consumers, secondary consumers, top carnivores, and decomposers.
C. producers, primary consumers, secondary consumers, and decomposers.
D. producers and decomposers.
E. producers, primary consumers, and decomposers.

Which two functional groups are always found in amino acids?

A. hydroxyl and aldehyde
B. phosphate and sulfhydryl
C. ketone and aldehyde
D. carbonyl and carboxyl
E. carboxyl and amino

Atom 1


Atom 2

Which of the following best describes the relationship between the atoms described below?

A. They are isotopes.
B. They each contain 1 neutron.
C. They are isomers.
D. They contain 1 and 3 protons, respectively.
E. They are polymers.

What do cohesion, surface tension, and adhesion have in common with reference to water?

A. All are produced by ionic bonding.
B. All are properties related to hydrogen bonding.
C. All increase when temperature increases.
D. All have to do with nonpolar covalent bonds.
E. C and D only

According to the competitive exclusion principle, two species cannot continue to occupy the same

A. range.
B. niche.
C. territory.
D. biome.
E. habitat.

According to the fluid mosaic model of cell membranes, which of the following is a true statement about membrane phospholipids?

A. They frequently flip-flop from one side of the membrane to the other.
B. They can move laterally along the plane of the membrane.
C. They occur in an uninterrupted bilayer, with membrane proteins restricted to the surface of the membrane.
D. They are free to depart from the membrane and dissolve in the surrounding solution.
E. They have hydrophilic tails in the interior of the membrane.

Which of the following statements correctly describes some aspect of protein excretion in prokaryotic cells?

A. Proteins that are excreted by prokaryotes are synthesized on ribosomes that are bound to the cytoplasmic surface of the plasma membrane.
B. The mechanism of protein excretion in prokaryotes is probably the same as that in eukaryotes.
C. Prokaryotes contain large pores in their plasma membrane that permit the movement of proteins out of the cell.
D. In prokaryotes, the ribosomes that are used for the synthesis of secreted proteins are located outside of the cell.
E. Prokaryotes are unlikely to be able to excrete proteins because they lack an endomembrane system.

Which of the following is not one of the four major groups of macromolecules found in living organisms?

A. carbohydrates
B. glucose
C. lipids
D. proteins
E. nucleic acids

Use the diagram of the U-tube in the figure below to answer the following questions. The solutions in the two arms of this U-tube are separated by a membrane that is permeable to water and glucose but not to sucrose. Side A is half filled with a solution of 2 M sucrose and 1 M glucose. Side B is half filled with 1 M sucrose and 2 M glucose. Initially, the liquid levels on both sides are equal.

Initially, in terms of tonicity, the solution in side A with respect to that in side B is

A. saturated.
B. hypertonic.
C. hypotonic.
D. plasmolyzed.
E. isotonic.

A patient has had a serious accident and lost a lot of blood. In an attempt to replenish body fluids, distilled water, equal to the volume of blood lost, is transferred directly into one of his veins. What will be the most probable result of this transfusion?

A. It will have no unfavorable effect as long as the water is free of viruses and bacteria.
B. The patient's red blood cells will shrivel up because the blood fluid is hypertonic compared to the cells.
C. The patient's red blood cells will shrivel up because the blood fluid is hypotonic compared to the cells.
D. The patient's red blood cells will swell because the blood fluid is hypotonic compared to the cells.
E. The patient's red blood cells will burst because the blood fluid is hypertonic compared to the cells.

A cell whose cytoplasm has a concentration of 0.02 molar glucose is placed in a test tube of water containing 0.02 molar glucose. Assuming that glucose is not actively transported into the cell, which of the following terms describes the tonicity of the external solution relative to the cytoplasm of the cell?

A. flaccid
B. isotonic
C. hypertonic
D. turgid
E. hypotonic

After the system reaches equilibrium, what changes are observed?

A. The molarity of sucrose and glucose are equal on both sides.
B. The molarity of glucose is higher in side A than in side B.
C. The water level is higher in side A than in side B.
D. The water level is unchanged.
E. The water level is higher in side B than in side A.

Celery stalks that are immersed in fresh water for several hours become stiff and hard. Similar stalks left in a salt solution become limp and soft. From this we can deduce that the cells of the celery stalks are

A. hypotonic to both fresh water and the salt solution.
B. hypertonic to both fresh water and the salt solution.
C. hypertonic to fresh water but hypotonic to the salt solution.
D. hypotonic to fresh water but hypertonic to the salt solution.
E. isotonic with fresh water but hypotonic to the salt solution.

Which of the following statements about membrane structure and function is false?

a. Diffusion of gases is faster in air than across membranes.
b. Diffusion, osmosis, and facilitated diffusion do not require any direct energy input from the cell. c. The types of proteins that are expose
d on one side of a membrane are nearly identical to those exposed on the other side of the membrane.
d. Voltage across the membrane depends on an unequal distribution of ions across the plasma membrane.
e. Special membrane proteins can cotransport two solutes by coupling diffusion down a concentration gradient to transport against the concentration gradient.

Read the following information and refer to the figure below to answer the following questions.

Five dialysis bags, constructed from a semi-permeable membrane that is impermeable to sucrose, were filled with various concentrations of sucrose and then placed in separate beakers containing an initial concentration of 0.6 M sucrose solution. At 10-minute intervals, the bags were massed (weighed) and the percent change in mass of each bag was graphed.

Which line represents the bag with the highest initial concentration of sucrose?

A. C
B. B
C. E
D. A
E. D

Read the following information and refer to the figure below to answer the following questions.

Five dialysis bags, constructed from a semi-permeable membrane that is impermeable to sucrose, were filled with various concentrations of sucrose and then placed in separate beakers containing an initial concentration of 0.6 M sucrose solution. At 10-minute intervals, the bags were massed (weighed) and the percent change in mass of each bag was graphed.

Which line represents the bag that contained a solution isotonic to the 0.6 molar solution at the beginning of the experiment?

A. D
B. E
C. C
D. A
E. B

Read the following information and refer to the figure below to answer the following questions.

Five dialysis bags, constructed from a semi-permeable membrane that is impermeable to sucrose, were filled with various concentrations of sucrose and then placed in separate beakers containing an initial concentration of 0.6 M sucrose solution. At 10-minute intervals, the bags were massed (weighed) and the percent change in mass of each bag was graphed.

Which line or lines represent(s) bags that contain a solution that is hypertonic at the end of 60 minutes?

A. D
B. D and E
C. B
D. C
E. A and B

Which fact does not result from strong hydrogen bonding between water molecules?

A. Water has strong cohesion tension.
B. Water has a relatively high boiling point.
C. Water is a universal solvent.
D. Water has a high specific heat.
E. Ice is less dense than water.

The pH of blood

A. is strongly basic.
B. is normally close to 7.4.
C. varies with the needs of the cell.
D. is strongly acidic.
E. is about 6.7.

Which of the following statements incorrectly describes common structural features of an animal secretory cell and a photosynthetic plant cell?

A. Both cells have mitochondria.
B. Both cells have a nucleus.
C. Both cells have a plasma membrane.
D. Both cells have Golgi apparatus.
E. Both cells have chloroplasts.

Which of the following is a reasonable explanation for why unsaturated fatty acids help keep any membrane more fluid at lower temperatures?

A. The double bonds block interaction among the hydrophilic head groups of the lipids.
B. The double bonds form a kink in the fatty acid tail, forcing adjacent lipids to be further apart.
C. Unsaturated fatty acids have a higher cholesterol content.
D. The double bonds result in a shorter fatty acid tail.
E. Unsaturated fatty acids permit more water in the interior of the membrane.

Of the following functions, which is most important for the glycoproteins and glycolipids of animal cell membranes?

A. a cell's ability to distinguish one type of neighboring cell from another
B. maintaining membrane fluidity at low temperatures
C. active transport of molecules against their concentration gradients
D. facilitated diffusion of molecules down their concentration gradients
E. maintaining the integrity of a fluid mosaic membrane

Glucose diffuses slowly through artificial phospholipid bilayers. The cells lining the small intestine, however, rapidly move large quantities of glucose from the glucose-rich food into their glucose-poor cytoplasm. Using this information, which transport mechanism is most probably functioning in the intestinal cells?

A. phagocytosis
B. facilitated diffusion
C. exocytosis
D. active transport pumps
E. simple diffusion

Water passes quickly through cell membranes because

A. it moves through aquaporins in the membrane.
B. it is a small, polar, charged molecule.
C. water movement is tied to ATP hydrolysis.
D. it moves through hydrophobic channels.
E. the bilayer is hydrophilic.

The chemical reactions involved in respiration are virtually identical between prokaryotic and eukaryotic cells. In eukaryotic cells, ATP is synthesized primarily on the inner membrane of the mitochondria. Where are the corresponding reactions likely to occur in prokaryotic respiration?

A. in the cytoplasm
B. on the nuclear envelope
C. on the plasma membrane
D. on the inner mitochondrial membrane
E. on the endoplasmic reticulum

Of the following, which is probably the most common route for membrane flow in the endomembrane system?
A. Golgi lysosome ER plasma membrane
B. ER chloroplasts mitochondrion cell membrane
C. tonoplast plasma membrane nuclear envelope smooth ER
D. rough ER vesicles Golgi plasma membrane
E. nuclear envelope lysosome Golgi plasma membrane

Which of the following is stored in the human liver for energy?

A. glycerol.
B. glucose.
C. glucagon.
D. glycine.
E. glycogen.

Which of these ecosystems has the highest net primary productivity per square meter?

A. temperate forest
B. boreal forest
C. open ocean
D. tropical rain forest
E. savanna

Which of the following statements about the cytoskeleton is incorrect?

A. Movement of cilia and flagella is the result of motor proteins causing microtubules to move relative to each other.
B. The dynamic aspect of cytoskeletal function is made possible by the assembly and disassembly of a few simple types of proteins into large aggregates.
C. Microfilaments are structurally rigid and resist compression, while microtubules resist tension (stretching).
D. Transport vesicles among the membranes of the endomembrane system depend on the function of the cytoskeleton.
E. Chemicals that block the assembly of the cytoskeleton would prevent many different processes in cells.

The high level of pesticides in birds of prey is an example of

A. exponential growth.
B. the principle of exclusion.
C. tcycling of nutrients by decomposers.
D. ecological succession.
E. biomagnification.

In the fractionation of homogenized cells using centrifugation, the primary factor that determines whether a specific cellular component ends up in the supernatant or the pellet is

A. the size and weight of the component.
B. the percentage of carbohydrates in the component.
C. the relative solubility of the component.
D. the presence or absence of lipids in the component.
E. the number of enzymes in the fraction.

Which of the following lists the biomes as they appear as you move from the equator to the North Pole?

a. tropical rain forest - taiga - tundra - desert - temperate deciduous forest
b. desert - tundra - taiga - temperate deciduous forest - tropical rain forest c. taiga - temperate deciduous fores
t - tundra - desert - tropical rain forest
d. tundra - taiga - temperate deciduous forest - desert - tropical rain forest
e. tropical rain forest - desert - temperate deciduous forest - taiga - tundra

The advantage of light microscopy over electron microscopy is that

A. light microscopy provides for higher magnification than electron microscopy.
B. light microscopy provides for higher resolving power than electron microscopy.
C. light microscopy allows one to view dynamic processes in living cells.
D. both A and B
E. both B and C

You are working on a team that is designing a new drug. In order for this drug to work, it must enter the cytoplasm of specific target cells. Which of the following would not be a factor that determines whether the molecule enters the cell?

A. lipid composition of the target cells' plasma membrane
B. charge on the drug molecule
C. size of the drug molecule
D. similarity of the drug molecule to other molecules transported by the target cells
E. polarity of the drug molecule

What is one of the functions of cholesterol in animal cell membranes?

A. stores energy
B. speeds diffusion
C. facilitates transport of ions
D. phosphorylates ADP
E. maintains membrane fluidity

Which of the following incorrectly matches the type of cell, type of protein, and site of the protein's synthesis?

A. prokaryote, secreted protein, free cytoplasmic ribosome
B. eukaryote, plasma membrane protein, rough ER
C. prokaryote, cytoplasmic protein, free cytoplasmic ribosome
D. prokaryote, plasma membrane protein, ribosome bound to plasma membrane
E. eukaryote, cytoplasmic protein, free cytoplasmic ribosome

After a membrane freezes and then thaws, it often becomes leaky to solutes. The most reasonable explanation for this is that

A. the lipid bilayer loses its fluidity when it freezes.
B. transport proteins become nonfunctional during freezing.
C. the solubility of most solutes in the cytoplasm decreases on freezing.
D. aquaporins can no longer function after freezing.
E. the integrity of the lipid bilayer is broken when the membrane freezes.

When a potassium ion ( ) moves from the soil into the vacuole of a cell on the surface of a root, it must pass through several cellular structures. Which of the following correctly describes the order in which these structures will be encountered by the ion?

A. secondary cell wall plasma membrane primary cell wall cytoplasm tonoplast
B. primary cell wall plasma membrane cytoplasm tonoplast
C. tonoplast primary cell wall plasma membrane cytoplasm
D. plasma membrane primary cell wall cytoplasm tonoplast
E. primary cell wall plasma membrane tonoplast cytoplasm vacuole

A species of fish is found to require a certain water temperature, a particular oxygen content of the water, a particular depth, and a rocky substrate on the bottom to thrive. These requirements are part of its

A. dimensional profile.
B. resource partition.
C. ecological niche.
D. prime habitat.
E. home base.

Which of the following statements is correct about diffusion?

A. It is a passive process in which molecules move from a region of higher concentration to a region of lower concentration.
B. It is very rapid over long distances.
C. It requires integral proteins in the cell membrane.
D. It requires an expenditure of energy by the cell.
E. It is an active process in which molecules move from a region of lower concentration to one of higher concentration.

A biologist ground up some plant leaf cells and then centrifuged the mixture to fractionate the organelles. Organelles in one of the heavier fractions could produce ATP in the light, while organelles in the lighter fraction could produce ATP in the dark. The heavier and lighter fractions are most likely to contain, respectively,

A. chloroplasts and mitochondria.
B. peroxisomes and chloroplasts.
C. chloroplasts and peroxisomes.
D. mitochondria and chloroplasts.
E. mitochondria and peroxisomes.

Which of the following best summarizes the relationship between dehydration reactions and hydrolysis?

A. A and C are correct.
B. Dehydration reactions assemble polymers, and hydrolysis breaks down polymers.
C. Hydrolysis only occurs in the urinary system, and dehydration reactions only occur in the digestive tract.
D. Hydrolysis creates monomers, and dehydration reactions break down polymers.
E. Dehydration reactions can occur only after hydrolysis.

Large numbers of ribosomes are present in cells that specialize in producing which of the following molecules?

A. proteins
B. glucose
C. starches
D. steroids
E. lipids

The experimental approach taken in current biological investigations presumes that

A. a life force ultimately controls the activities of living organisms and this life force cannot be studied by physical or chemical methods.
B. living organisms are composed of the same elements present in nonliving things, plus a few special trace elements found in only living organisms or their products.
C. although a life force, or vitalism, exists in living organisms, this life force cannot be studied by physical or chemical methods.
D. simple organic compounds can be synthesized in the laboratory from inorganic precursors, but complex organic compounds like carbohydrates and proteins can only be synthesized by living organisms.
E. living organisms can be understood in terms of the same physical and chemical laws that can be used to explain all natural phenomena.

A series of enzymes catalyze the reaction X Y Z A. Product A binds to the enzyme that converts X to Y at a position remote from its active site. This binding decreases the activity of the enzyme.

What is substance X?

A. a substrate
B. an intermediate
C. a coenzyme
D. the product
E. an allosteric inhibitor

A series of enzymes catalyze the reaction X Y Z A. Product A binds to the enzyme that converts X to Y at a position remote from its active site. This binding decreases the activity of the enzyme.

Substance A functions as

A. a coenzyme.
B. a competitive inhibitor.
C. the substrate.
D. an allosteric inhibitor.
E. an intermediate.

The figure below shows the absorption spectrum for chlorophyll a and the action spectrum for photosynthesis. Why are they different?

A. Other pigments absorb light in addition to chlorophyll a.
B. Oxygen given off during photosynthesis interferes with the absorption of light.
C. Green and yellow wavelengths inhibit the absorption of red and blue wavelengths.
D. Aerobic bacteria take up oxygen which changes the measurement of the rate of photosynthesis.
E. Bright sunlight destroys photosynthetic pigments.

A maple leaf is at which level in the hierarchy of biological organization?

A. organ
B. cell
C. organ system
D. tissue
E. organelle

Where is the electron transport chain found in plant cells?

A. matrix of mitochondria
B. cytoplasm
C. thylakoid membranes of chloroplasts
D. stroma of chloroplasts
E. inner membrane of mitochondria

Where do the enzymatic reactions of the Calvin cycle take place?

A. thylakoid space Refer to the figure below, showing the citric acid cycle, as a guide to answer the following questions.
B. thylakoid membranes
C. electron transport chain
D. stroma of the chloroplast
E. outer membrane of the chloroplast

Starting with citrate, how many of the following would be produced with three turns of the citric acid cycle?

A. 2 ATP, 2 CO2, 1 NADH, and 3 FADH2
B. 3 ATP, 6 CO2, 9 NADH, and 3 FADH2
C. 1 ATP, 2 CO2, 3 NADH, and 1 FADH2
D. 38 ATP, 6 CO2, 3 NADH, and 12 FADH2
E. 3 ATP, 3 CO2, 3 NADH, and 3 FADH2

Carbon skeletons for amino acid biosynthesis are supplied by intermediates of the citric acid cycle. Which intermediate would supply the carbon skeleton for synthesis of a five-carbon amino acid?

A. malate
B. citrate
C. -ketoglutarate
D. succinate
E. isocitrate

For each molecule of glucose that is metabolized by glycolysis and the citric acid cycle, what is the total number of NADH + FADH2 molecules produced?

A. 4
B. 12
C. 10
D. 6
E. 5

Starting with one molecule of isocitrate and ending with fumarate, what is the maximum number of ATP molecules that could be made through substrate-level phosphorylation?

A. 11
B. 2
C. 12
D. 1
E. 24

Carbon dioxide (CO2) is released during which of the following stages of cellular respiration?

A. glycolysis and the oxidation of pyruvate to acetyl CoA
B. the citric acid cycle and oxidative phosphorylation
C. fermentation and glycolysis
D. oxidation of pyruvate to acetyl CoA and the citric acid cycle
E. oxidative phosphorylation and fermentation

During aerobic cellular respiration, a proton gradient in mitochondria is generated by ____ and used primarily for ____.

A. the electron transport chain; substrate-level phosphorylation
B. the electron transport chain; ATP synthesis
C. glycolysis; production of H2O
D. diffusion of protons; ATP synthesis
E. fermentation; NAD+ reduction

Which of the following forms of energy is least available to accomplish cellular work?

A. mechanical energy
B. light energy
C. electrical energy
D. potential energy
E. thermal energy (heat)

Which process could be compared to how rushing steam turns a water wheel?

A. ATP synthase activity
B. formation of NADH in glycolysis
C. the electron transport system
D. the citric acid cycle
E. oxidative phosphorylation

Indicate whether the following events occur during
A. photosynthesis
B. respiration
C. both photosynthesis and respiration
D. neither photosynthesis nor respiration

reduction of oxygen which forms water

a. A
b. B
c. C
d. D

Indicate whether the following events occur during
A. photosynthesis
B. respiration
C. both photosynthesis and respiration
D. neither photosynthesis nor respiration

reduction of NADP+

a. A
b. B
c. C
d. D

Indicate whether the following events occur during
A. photosynthesis
B. respiration
C. both photosynthesis and respiration D. neither photosynthesis nor respiration

generation of proton gradients across membranes

a. A
b. B
c. C
d. D

Indicate whether the following events occur during
A. photosynthesis
B. respiration
C. both photosynthesis and respiration D. neither photosynthesis nor respiration

synthesis of ATP by the chemiosmotic mechanism

a. A
b. B
c. C
d. D

Indicate whether the following events occur during
A. photosynthesis
B. respiration
C. both photosynthesis and respiration
D. neither photosynthesis nor respiration

the splitting of carbon dioxide to form oxygen gas and carbon compounds

a. A
b. B
c. C
d. D

Prokaryotic and eukaryotic cells generally have which of the following features in common?

A. ribosomes
B. linear chromosomes made of DNA and protein
C. a cell wall made of cellulose
D. a membrane-bounded nucleus
E. flagella or cilia that contain microtubules

Which curve represents the behavior of an enzyme taken from a bacterium that lives in hot springs at temperatures of 70°C or higher?

A. curve 4
B. curve 5
C. curve 3
D. curve 1
E. curve 2

Which curve was most likely generated from analysis of an enzyme from a human stomach where conditions are strongly acid?

A. curve 1
B. curve 5
C. curve 4
D. curve 3
E. curve 2

Which curve was most likely generated from an enzyme that requires a cofactor?

A. curve 5
B. curve 2
C. It is not possible to determine whether an enzyme requires a cofactor from these data.
D. curve 4
E. curve 1

Which of the following types of cells utilize deoxyribonucleic acid (DNA) as their genetic material?

A. A, B, and C
B. plant
C. archaea
D. A and B only
E. animal

Which of the following sequences represents the hierarchy of biological organization from the least to the most complex level?

A. cell, community, population, organ system, molecule, organelle
B. organelle, tissue, biosphere, ecosystem, population, organism
C. molecule, cell, organ system, population, ecosystem, biosphere
D. ecosystem, cell, population, tissue, organism, organ system
E. organism, community, biosphere, molecule, tissue, organ

Once labor begins in childbirth, contractions increase in intensity and frequency until delivery. The increasing labor contractions of childbirth are an example of

A. a bioinformatic system.
B. positive feedback.
C. negative feedback.
D. feedback inhibition.
E. both C and D

Which of the following properties or processes do we associate with living things?

A. evolutionary adaptations
B. energy processing
C. responding to the environment
D. growth and reproduction
E. all of the above

Where is ATP synthase located in the mitochondrion?

A. inner membrane
B. electron transport chain
C. outer membrane
D. cytosol
E. mitochondrial matrix

According to the induced fit hypothesis of enzyme catalysis, which of the following is CORRECT?

A. The binding of the substrate depends on the shape of the active site.
B. The binding of the substrate changes the shape of the enzyme's active site.
C. The active site creates a microenvironment ideal for the reaction.
D. Some enzymes change their structure when activators bind to the enzyme.
E. A competitive inhibitor can outcompete the substrate for the active site.

During aerobic respiration, electrons travel downhill in which sequence?

A. food citric acid cycle ATP NAD+
B. food NADH electron transport chain oxygen
C. food glycolysis citric acid cycle NADH ATP
D. glucose ATP electron transport chain NADH
E. glucose pyruvate ATP oxygen

Which of the following statements is true concerning the figure?

A. It represents cell processes involved in C4 photosynthesis.
B. A, B, and C are true.
C. It represents an adaptation that minimizes photorespiration.
D. A and C are true.
E. It represents the type of cell structures found in CAM plants.

Plants that fix CO2 into organic acids at night when the stomata are open and carry out the Calvin cycle during the day when the stomata are closed are called

A. C3 plants.
B. CAM plants.
C. B and C only.
D. A, B, and C
E. C4 plants.

An enzyme catalyzes a reaction by

A. supplying the energy to speed up a reaction.
B. changing the equilibrium of a spontaneous reaction.
C. lowering the G of a reaction.
D. increasing the amount of free energy of a reaction.
E. lowering the energy of activation of a reaction.

Which metabolic pathway is common to both cellular respiration and fermentation?

A. oxidative phosphorylation
B. the oxidation of pyruvate to acetyl CoA
C. the citric acid cycle
D. glycolysis
E. chemiosmosis

A young relative of yours has never had much energy. He goes to a doctor for help and is sent to the hospital for some tests. There they discover his mitochondria can use only fatty acids and amino acids for respiration, and his cells produce more lactate than normal. Of the following, which is the best explanation of his condition?

A. His mitochondria lack the transport protein that moves pyruvate across the outer mitochondrial membrane.
B. His cells lack the enzyme in glycolysis that forms pyruvate.
C. His cells cannot move NADH from glycolysis into the mitochondria.
D. His cells have a defective electron transport chain, so glucose goes to lactate instead of to acetyl CoA.
E. His cells contain something that inhibits oxygen use in his mitochondria.

The primary role of oxygen in cellular respiration is to

A. catalyze the reactions of glycolysis.
B. combine with carbon, forming CO2.
C. combine with lactate, forming pyruvate.
D. act as an acceptor for electrons and hydrogen, forming water.
E. yield energy in the form of ATP as it is passed down the respiratory chain.

What are the products of noncyclic photophosphorylation?

A. ATP and NADPH
B. ATP and P700
C. P700 and P680
D. heat and fluorescence
E. ADP and NADP

What are the basic "building blocks" of deoxyribonucleic acid (DNA)?

A. 4 different kinds of nucleotides
B. 20 different kinds of amino acids
C. 3 different kinds of genomes
D. 100,000 different kinds of proteins
E. 26 different kinds of chromosomes

ATP generally energizes a cellular process by

A. coupling free energy released by ATP hydrolysis to free energy needed by other reactions.
B. binding directly to the substrate(s) of the enzyme.
C. releasing heat upon hydrolysis.
D. breaking a high-energy bond.
E. acting as a catalyst.

When blood glucose level rises, the pancreas secretes insulin, and as a result blood glucose level declines. When blood glucose level is low, the pancreas secretes glucagon, and as a result blood glucose level rises. Such regulation of blood glucose level is the result of

A. catalytic feedback.
B. negative feedback. d. bioinformatic regulation.
C. positive feedback.
e. both A and B

What does a frequency of recombination of 50% indicate?

A. Abnormal meiosis has occurred.
B. The genes are located on sex chromosomes.
C. Independent assortment is hindered.
D. All of the offspring have combinations of traits that match one of the two parents.
E. The two genes likely are located on different chromosomes.

All of the following occur during prophase of mitosis in animal cells except

A. the nucleolus can no longer be seen.
B. the centrioles move toward opposite poles.
C. chromosomes are duplicated.
D. the nuclear envelope disappears.
E. the spindle is organized.

Plants convert the energy of sunlight into

A. the energy of motion.
B. minerals.
C. carbon dioxide and water.
D. the potential energy of chemical bonds.
E. kinetic energy.

Which of the following is not true of cell communication systems?

A. Most signal receptors are bound to the outer membrane of the nuclear envelope.
B. Cell signaling was an early event in the evolution of life.
C. In response to a signal, the cell may alter activities by changes in cytosol activity or in transcription of DNA.
D. Communicating cells may be far apart or close together.
E. Protein phosphorylation is a major mechanism of signal transduction.

The pedigree chart below is for a family, some of whose members exhibit the recessive trait, wooly hair. Affected individuals are indicated by an open square or circle. Use the chart to answer the following question.
What is the probability that individual C-1 is Ww?

A. 2/4
B. 3/4
C. 2/3
D. 1/4
E. 1