AP Biology Multiple Choice Exam

A dog is following the scent of a jackrabbit. Which of the following accurately describes how the dog's brain integrates information for smell?

A) Chemoreceptors in the brain send impulses for smell in the nasal cavity.

B) Chemoreceptor cells in the nasal cavity sends impulses to the appropriate area of the brain.

C) Chemoreceptors on epithelial cells of the tongue send hormones to the appropriate area of the brain.

D) Receptors originating in the nose send action potentials to the motor regions of the brain.

B) Chemoreceptor cells in the nasal cavity sends impulses to the appropriate area of the brain.

Thrips are insects that feed on rose pollen. Scientists noted that the thrips population increased in the spring and decreased dramatically during the summer. The researchers hypothesized that food abundance was the limiting factor for the population. Which of the following types of data would be most useful for the scientists to collect at regular intervals on a designated test plot of rose plants?

A) Amount of sunlight (hours/day)

B) Mean temperature (oC)

C) Density of rose pollen produced (g/m2)

D) Amount of pollen produced by each flower

(g/flower)

C) Density of rose pollen produced (g/m2)

If ATP breakdown (hydrolysis) is inhibited, which of the following types of movement across cell membranes is also inhibited?

A) Movement of oxygen into a cell

B) Movement of water through aquaporins

C) Passage of a solute against its concentration

gradient

D) Facilitated diffusion of a permeable

substance

C) Passage of a solute against its concentration

Undersea landslides can disrupt marine habitats by burying organisms that live on the ocean floor. The graph above shows the size of a population of a certain organism that lives on the ocean floor. The population was affected by a recent landslide at the time indicated on the graph. Which of the following best predicts how the population will be affected by the landslide?

A) The surviving organisms will evolve into a new species.

B) The reduced population will likely have allelic frequencies that are different from the initial population.

C) The population will adapt to deeper waters to avoid future landslides.

D) The reduced population will have a greater number of different genes than the initial population.

B) The reduced population will likely have allelic frequencies that are different from the initial population.

Which of the following questions is most relevant to understanding the Calvin cycle?

A) How does chlorophyll capture light?

B) How is ATP used in the formation of 3-carbon carbohydrates?

C) How is NADP+ reduced to NADPH?

D) How is ATP produced in chemiosmosis?

B) How is ATP used in the formation of 3-carbon carbohydrates?

H+ + HCO3- <-> H20 +CO2

The equation above shows one of the reversible reactions that occur in blood. After exercise, an athlete's blood pH has dropped below the normal level. How will normal blood pH be restored?

A) An increase in O2 concentration in the plasma will lead to an increase in H+ concentration.

B) An increase in temperature will lead to an increase in H+ concentration.

C) An increase in sweating will lead to a decrease in OH - and H+ concentration

D) An increase in breathing rate will lead to a decrease in blood CO2 and H+ concentration.

D) An increase in breathing rate will lead to a decrease in blood CO2 and H+ concentration.

A researcher is investigating the relationship between the existing species diversity in a community and the ability of an introduced nonnative species to destabilize the community. Which of the following graphs is most consistent with the claim that communities with high diversity are more resistant to change than are communities with low diversity?

D)

Under which of the following conditions is the observed number of beetles per culture dish the greatest?

A) T. confusum with parasite at 500 days

B) T. confusum without parasite at 300 days

C) T. castaneum with parasite at 100 days

D) T. castaneum with parasite at 600 days

C) T. castaneum with parasite at 100 days

The data over the duration of the experiment provide the strongest support for which of the following conclusions regarding the effect of the parasite on Tribolium populations?

A) T. confusum is adversely affected by the parasite, while T. castaneum is not.

B) T. castaneum is adversely affected by the parasite, while T. confusum is not.

C) Both T. confusum and T. castaneum are adversely affected by the parasite.

D) Both T. confusum and T. castaneum show increased fitness in the presence of the parasite.

B) T. castaneum is adversely affected by the parasite, while T. confusum is not.

In Figure I, the difference between the two curves can best be attributed to which of the following?

A) The difference between controlled laboratory conditions and the natural environment

B) The effect of the host on its parasite

C) The influence of competition for limited

resources

D) The natural variation among populations

D) The natural variation among populations

If the experiment was continued for an additional 500 days, the population density of T. castaneum with the parasite would most likely stabilize at a value closest to which of the following?

A) 5 beetles/culture dish

B) 10 beetles/culture dish

C) 20 beetles/culture dish

D) 25 beetles/culture dish

B) 10 beetles/culture dish

The vertebrate forelimb initially develops in the embryo as a solid mass of tissue. As development progresses, the solid mass near the end of the forelimb is remodeled into individual digits. Which of the following best explains the role of apoptosis in remodeling of the forelimb?

A) Apoptosis replaces old cells with new ones that are less likely to contain mutations.

B) Apoptosis involves the regulated activation of proteins in specific cells of the developing

forelimb that leads to the death of those cells.

C) Apoptosis involves the destruction of extra cells in the developing forelimb, which

provides nutrients for phagocytic cells.

D) Apoptosis in the developing forelimb triggers the differentiation of cells whose fate was

not already determined.

B) Apoptosis involves the regulated activation of proteins in specific cells of the developing

What most likely causes the trends in oxygen concentration shown in the graph above?

A) The water becomes colder at night and thus holds more oxygen.

B) Respiration in most organisms increases at night.

C) More organisms are respiring at night than during the day.

D) Photosynthesis produces more oxygen than is consumed by respiration during the day.

D) Photosynthesis produces more oxygen than is consumed by respiration during the day.

Data regarding the presence (+) or absence (-) of five derived traits in several different species are shown in the table below.

Which of the following cladograms provides the simplest and most accurate representation of the data in the table?

A)

A common laboratory investigation involves putting a solution of starch and glucose into a dialysis bag and suspending the bag in a beaker of water, as shown in the figure below.

The investigation is aimed at understanding how molecular size affects movement through a membrane. Which of the following best represents the amount of starch, water, and glucose in the dialysis bag over the course of the investigation?

A)

The divergence between the two populations of Rhagoletis must have occurred very rapidly because

A) the apple tree was imported into North America with European settlement approximately 200 years ago

B) flies were imported into North America with European settlement approximately 200 years ago

C) long-distance rail transport of fruit increased only after the American Civil War (1861 -1865)

D) heavy use of gunpowder during the American Civil War (1861 -1865) led to increased mutation rates in many natural populations of plants and animals

A) the apple tree was imported into North America with European settlement approximately 200 years ago

Initially, which of the following isolating mechanisms is likely to have been the most important in preventing gene flow between the two populations of Rhagoletis?

A) Gamete incompatibility

B) Temporal isolation

C) Mechanical isolation

D) Reduced hybrid viability

B) Temporal isolation

Matings between individuals from the two populations of Rhagoletis produce hybrid flies that appear to be healthy and have normal life spans. The eggs laid by these hybrid flies, however, hatch less often than those of flies from either of the two populations. What isolating mechanism seems to be important in this hybrid population?

A) Prezygotic isolation

B) Mechanical isolation

C) Reduced hybrid fertility

D) Habitat isolation

C) Reduced hybrid fertility

A group of mice was released into a large field to which no other mice had access. Immediately after the release, a representative sample of the mice was captured, and the fur color of each individual in the sample was observed and recorded. The mice were then returned to the field. After twenty years, another representative sample of the mice was captured, and the fur color of each individual in the sample was again recorded. Which of the following best explains the change in the frequency distribution of fur color phenotypes in the mouse population, as shown in the figures above?

A) The allele for gray fur color is unstable, and over twenty years most of those alleles mutated to become

alleles for black fur.

B) The field was composed primarily of light-colored soil and little vegetation, affording gray mice protection from predators.

C) Sexual selection led to increased mating frequency of black and brown versus gray and brown.

D) The gray mice were hardest to capture and so were underrepresented in the twenty-year sample.

B) The field was composed primarily of light-colored soil and little vegetation, affording gray mice

Scientists have found that the existing populations of a certain species of amphibian are small in number, lacking in genetic diversity, and separated from each other by wide areas of dry land. Which of the following human actions is most likely to improve the long-term survival of

the amphibians?

A) Cloning the largest individuals to counteract the effects of aggressive predation

B) Reducing the population size by one-fifth to decrease competition for limited resources

C) Constructing a dam and irrigation system to control flooding

D) Building ponds in the areas of dry land to promote interbreeding between the separated populations

D) Building ponds in the areas of dry land to promote interbreeding between the separated populations

To determine the evolutionary history and relationships among organisms, scientists gather evidence from a wide variety of sources including paleontology, embryology, morphology, behavior, and molecular biology. A phylogenetic tree of vertebrates is shown. Which of the following statements is most consistent with the phylogenetic tree shown?

A) Birds and turtles evolved their own means of gas exchange independently of the other vertebrates.

B) Mammals are most closely related to birds because they share a direct common ancestor.

C) The common ancestor of reptiles, birds, and mammals produced amniotic eggs.

D) Crocodiles are direct descendents of ray-finned fishes since they live in the same

environment.

C) The common ancestor of reptiles, birds, and mammals produced amniotic eggs.

The diagram above depicts the response to a pinprick (stimulus) on the tip of a human finger. The arrows show the direction of impulse transmission along the labeled axons. If axon II was damaged before the pinprick, which of the following is most likely?

A) The person will not feel the pinprick.

B) The person can no longer feel pain.

C) The person's finger will not withdraw reflexively.

D) The person cannot transmit nerve impulses to the brain.

C) The person's finger will not withdraw reflexively.

In the Arctic Ocean, the predominant primary producers are phytoplankton. Phytoplankton are consumed by zooplankton, which in turn are eaten by codfish. In years when there is more open water (less ice coverage), there are more zooplankton and fish than in years with less open water (more ice coverage). Based on the graph above, the difference is most likely because

A) when there is less open water, light is blocked from the zooplankton, so they cannot produce as much food for the fish

B) when there is more open water, the

temperature is warmer, so the zooplankton and fish populations increase in size

C) the ice blocks the light, so in years with more ice coverage, there is less photosynthesis by the phytoplankton

D) the ice increases the light available for photosynthesis, so primary production increases and zooplankton populations increase in size

C) the ice blocks the light, so in years with more ice coverage, there is less photosynthesis by the phytoplankton

The diagram above illustrates feedback control as exerted by the hormone thyroxine. Following surgical removal of the thyroid gland, the level of TSH in the blood will increase. Which of the following best explains this increase?

A) Residual blood thyroxine, from prior to thyroid gland removal, will bind to cells in the anterior pituitary, signaling more TSH secretion.

B) Thyroxine will remain bound to thyroxine receptors on various body cells, and these body cells will secrete additional hormones that stimulate the anterior pituitary to secrete TSH.

C) Thyroxine that was stored in the anterior pituitary prior to thyroid gland removal will signal more TSH secretion.

D) A decrease in thyroxine levels means a loss of inhibition to the hypothalamus and anterior pituitary, leading to increased TSH secretion.

D) A decrease in thyroxine levels means a loss of inhibition to the hypothalamus and anterior pituitary, leading to increased TSH secretion.

Which of the following provides the best indication that light is required for the activation of electron transfer reactions in chloroplasts?

A) Calculating the rate of change of the absorbance for sample 1

B) Comparing the observed results for sample 2 and sample 3

C) Repeating the entire experimental procedure at night

D) Including multiple trials for all the samples

B) Comparing the observed results for sample 2 and sample 3

Which of the following can be reasonably concluded from the experimental results?.

A) Chloroplasts must be suspended in a buffer solution to function properly.

B) The optimal temperature for activation of electron transfer is 25o C.

C) DCPIP inhibits biochemical reactions in suspended chloroplasts.

D) Light from a lamp can substitute for sunlight in stimulating chloroplast processes

D) Light from a lamp can substitute for sunlight in stimulating chloroplast processes

If an additional sample containing the chloroplast/DCPIP solution was placed at a distance of 90 cm from the lamp, which of the following predictions would be most consistent with the experimental results?

A) The concentration of DCPIP in the solution will increase exponentially.

B) The absorbance at 60 minutes will be roughly equal to 1.4.

C) The change in absorbance over time in the solution will be less than that of the other samples.

D) The temperature of the solution will exceed 75o C.

C) The change in absorbance over time in the solution will be less than that of the other samples.

Which of the following descriptions of photosynthesis best explains the results of the experiment?

A) Availability of electrons for transfer to DCPIP depends on light energy.

B) Movement of DCPIP across chloroplast membranes occurs in less than 60 minutes.

C) Chlorophyll molecules degrade rapidly in the presence of DCPIP.

D) DCPIP can only be used to measure photosynthetic activity at low light levels.

A) Availability of electrons for transfer to DCPIP depends on light energy.

Which of the following scientific questions could be investigated using a similar experimental setup?

A) How much carbon dioxide is required by a plant cell to produce one molecule of glucose?

B) What wavelength of light best activates electron transfer reactions in chloroplasts?

C) Which molecule in chloroplasts accepts activated electrons from DCPIP during photosynthesis?

D) Are the same genes that are expressed in chloroplasts also expressed in mitochondria?

B) What wavelength of light best activates electron transfer reactions in chloroplasts?

The figure above shows a model of a ligand precursor being cleaved to produce an active ligand that binds to a specific receptor. Which of the following is most likely to reduce the binding of the active ligand to its receptor?

A) A change in the cytoskeletal attachment of transmembrane proteins

B) The presence of a large amount of the precursor form of the ligand

C) An increase in the ratio of the number of unsaturated to the number of saturated fatty acid

tails of the membrane lipids

D) A mutation in the receptor gene that causes a substitution of a charged amino acid for a

nonpolar amino acid

in the ligand binding site of the receptor

D) A mutation in the receptor gene that causes a substitution of a charged amino acid for a

nonpolar amino acid

in the ligand binding site of the receptor

Students in a class measured the mass of various living organisms. They then kept the organisms in the dark for 24 hours before remeasuring them. None of the organisms were provided with nutrients during the 24-hour period. The data are as follows.

Which of the following is the best explanation for the pattern of change in mass of the organisms over time?

A) Water loss due to evaporation

B) Cellular respiration

C) The law of conservation of matter

D) Growth and reproduction

B) Cellular respiration

Antidiuretic hormone (ADH) is important in maintaining homeostasis in mammals. ADH is released from the hypothalamus in response to high tissue osmolarity. In response to ADH, the collecting duct and distal tubule in the kidney become more permeable to water, which increases water reabsorption into the capillaries. The amount of hormone released is controlled by a negative feedback loop. Based on the model presented, which of the following statements expresses the proper relationship between osmolarity, ADH release, and urine production?

A) As tissue osmolarity rises, more ADH is released, causing less water to be excreted as urine

B) As tissue osmolarity rises, less ADH is released, causing less water to be excreted as urine

C) As tissue osmolarity rises, more ADH is released, causing more water to be excreted as urine

D) As tissue osmolarity rises, less ADH is released, causing more water to be excreted as urine.

A) As tissue osmolarity rises, more ADH is released, causing less water to be excreted as urine

Which of the following procedures was most likely followed to determine the change in beak size?

A) A few finches were trapped in 1981 and again in 1987, and their beak sizes were compared.

B) The beak size in fifteen finches was measured in 1987, and the beak size in the original finches was determined by estimation.

C) The beak size in a large number of finches was measured every year from 1981 to 1987.

D) Finches were captured and bred in 1981, and the beak size of the offspring was measured

C) The beak size in a large number of finches was measured every year from 1981 to 1987.

Which of the following statements might best explain the increase in average beak size in the finch population during the drought?

A) Finches with bigger beaks are better able to crack thick-walled seeds and produce more surviving offspring.

B) Finches with bigger beaks can attack and kill finches with smaller beaks.

C) Finches with bigger beaks possess more powerful flight muscles and are able to find more food.

D) Finches that crack large seeds develop larger beaks over time.

A) Finches with bigger beaks are better able to crack thick-walled seeds and produce more surviving offspring.

Which of the following best describes the mechanism behind the change in beak size in the finch population?

A) The formation of two new finch species from a single parent species

B) A change in gene frequencies in the finch population due to selective pressure from the environmental change

C) A new allele appearing in the finch population as a result of mutation

D) The achievement of dynamic equilibrium in the finch population as a result of homeostasis

B) A change in gene frequencies in the finch population due to selective pressure from the environmental change

The biologist discovered that from 1988 to 1993, the average beak size declined to pre-1981 levels. The reversal in beak size from 1988 to 1993 was most likely related to which of the following events?

A) A loss of food supply for the finches

B) The end of the drought

C) An increase in drought conditions

D) An increase in predators consuming finches

B) The end of the drought

57. Five new species of bacteria were discovered in Antarctic ice core samples. The nucleotide (base) sequences of rRNA subunits were determined for the new species. The table below shows the number of nucleotide differences between the species.

Which of the following phylogenetic trees is most consistent with the data?

C)

Which of the following includes the most likely change in the coloration of the beetle population after pollution and a correct rationale for the change?

A) The coloration range shifted toward more light-colored beetles, as in diagram I. The pollution helped the predators find the darkened tree trunks.

B) The coloration in the population split into two extremes, as in diagram II. Both the lighter-colored and the darker-colored beetles were able to hide on the darker tree trunks.

C) The coloration range became narrower, as in diagram III. The predators selected beetles

at the color extremes.

D) The coloration in the population shifted toward more darker-colored beetles, as in diagram IV. The lightercolored beetles were found more easily by the predators than were the darker-colored beetles.

D) The coloration in the population shifted toward more darker-colored beetles, as in diagram IV. The lightercolored beetles were found more easily by the predators than were the darker-colored beetles.

The area covered by tropical rain forest is reduced by millions of hectares per year due to agriculture and logging. Which of the following best describes a likely result of tropical rain forest deforestation?

A) Populations of plants and animals will decrease as more rain forest disappears, leading to a decrease in biodiversity.

B) An increase of soil moisture will lead to a rapid increase in new vegetation coverage.

C) An increase in atmospheric carbon dioxide will lead to higher levels of ultraviolet

radiation reaching the surface of Earth.

D) More oxygen will be available to other organisms as plant numbers decrease.

A) Populations of plants and animals will decrease as more rain forest disappears, leading to a decrease in biodiversity.

The diagram above shows the progression of ecological events after a fire in a particular ecosystem. Based on the diagram, which of the following best explains why the oak trees are later replaced by other trees?

A) Eventually the other trees grow taller than the oak trees and form a dense canopy that shades the understory.

B) Oak trees alter the pH of the soil, making the forest better suited for shrubs and other trees.

C) Roots of shrubs proliferate in the soil of the forest and prevent the oak trees from obtaining water.

D) Oak trees succumb to environmental pollutants more readily than do either the shrubs or the other trees.

A) Eventually the other trees grow taller than the oak trees and form a dense canopy that shades the understory.

In most freshwater fish, nitrogenous waste is primarily excreted as ammonia, which is highly soluble in water and is toxic at lowconcentrations. In terrestrial mammals, ammonia is converted to urea before it is excreted. Urea is also highly soluble in water but is less toxic than ammonia at low concentrations. Which of the following best explains why freshwater fish do not convert ammonia to urea for excretion?

A) The metabolic pathways of fish do not normally involve nitrogen consumption.

B) The dilution of ammonia by direct excretion into freshwater conserves energy.

C) Ammonia is concentrated in tissues, where it is stored prior to excretion.

D) The nitrogen in ammonia is recycled for use in protein and nucleotide synthesis.

B) The dilution of ammonia by direct excretion into freshwater conserves energy.

Which of the following statements most directly supports the claim that different species of organisms use different metabolic strategies to meet their energy requirements for growth, reproduction, and homeostasis?

A) During cold periods pond-dwelling animals can increase the number of unsaturated fatty acids in their cell membranes while some plants make antifreeze proteins to prevent ice crystal formation in tissues

B) Bacteria lack introns while many eukaryotic genes contain many of these intervening sequences.

C) Carnivores have more teeth that are specialized for ripping food while herbivores have more teeth that are specialized for grinding food.

D) Plants generally use starch molecules for storage while animals use glycogen and fats for storage.

D) Plants generally use starch molecules for storage while animals use glycogen and fats for storage.

Arctic foxes typically have a white coat in the winter. In summer, when there is no snow on the ground, the foxes typically have a darker coat. Which of the following is most likely responsible

for the seasonal change in coat color?

A) The decrease in the amount of daylight in winter causes a change in gene expression, which results in the foxes growing a lighterappearing coat.

B) The diet of the foxes in summer lacks a particular nutrient, which causes the foxes to lose their white coat and grow a darker colored coat.

C) Competition for mates in the spring causes each fox to increase its camouflage with the environment by producing a darkerappearing coat.

D) The lower temperatures in winter denature the pigment molecules in the arctic fox coat, causing the coat to become lighter in color.

A) The decrease in the amount of daylight in winter causes a change in gene expression, which results in the foxes growing a lighterappearing coat.