Prepare for the AP Biology exam with this practice test and answers. This guide covers cell biology, genetics, evolution, ecology, and all major topics tested on the College Board exam.
Q: Humans produce sweat as a cooling mechanismto maintain a stable internal temperature. Whichof the following best explains how the propertiesof water contribute to this physiological process?
Answer: The high heat of vaporization of waterallows the body to remove excess heatthrough a phase change of water fromliquid to gas
Q: A student placed a semipermeable membraneinside a U-shaped channel with two chambers,as shown. The membrane permits the movementof water but not salt. The student wants to varythe rate of osmosis that occurs across themembrane. Which of the followingexperimental designs will result in the fastest netrate of water movement into chamber A?
Answer: Placing salt water in chamber A anddistilled water in chamber B
Q: Which of the following best describes the role ofwater in photosynthesis?
Answer: Water molecules donate electrons to theelectron transport chain
Q: What evolutionary advantage doescompartmentalization of core metabolicprocesses offer eukaryotes?
Answer: Evolution of a nucleus in eukaryotesseparates the processes of transcriptionand translation and they can be regulatedseparately
Q: Which of the following best describes thecellular location where pyruvate dehydrogenaseis most likely active?
Answer: The mitochondrial matrix
Q: The maximum production rate of acetyl-CoAunder condition 1 is closest to which of thefollowing?
Answer: 1 micromole/sec
Q: Which of the following observations providesthe best evidence that acetyl-CoA negativelyregulates pyruvate dehydrogenase activity?
Answer: The rate of the pyruvatedehydrogenase-catalyzed reaction isslower in the presence of a higherconcentration of acetyl-CoA
Q: Pyruvate dehydrogenase deficiency is a geneticdisease most commonly linked to a mutation inthe a -subunit of the mitochondrial enzyme thatcauses the enzyme to cease functioning. As aresult of the mutation, affected individuals buildup dangerous amounts of lactic acid. Which ofthe following best explains the buildup of lacticacid in individuals with the mutation?
Answer: Cells undergo fermentation becausepyruvate cannot be metabolized toproceed into the Krebs cycle
Q: The diagram shows how water can adhere to thexylem in the stems of plants, which contributesto water movement in the plant. Which of thefollowing best explains how water is able tomove upward from the roots of a plant, throughits xylem in the stem, and out to the leaves?
Answer: Water and the xylem are both polar. Watermolecules have the ability to formhydrogen bonds with each other and withthe walls of the xylem
Q: Protein X activates gene expression only in cellsexposed to a specific signaling molecule. In astudy, researchers determined the intracellularlocation of Protein X in cultured cells bothbefore and after exposing the cells to thesignaling molecule. The results of the study areshown in the diagram
Answer: Protein X is a transcription factor
Q: The hormone prolactin has varying effects inmany different animal species. All vertebratesproduce prolactin, which is involved in signaltransduction pathways. In mammals, prolactinstimulates the production of milk in mammaryglands. In fish, prolactin plays an important rolein osmoregulation. In birds, prolactin isinvolved in lipid metabolism.Which of the following best explains thepresence of prolactin in various vertebratespecies?
Answer: Prolactin is a homologous hormonebecause it has a common origin butdifferent functions in various species
Q: Which of the following best describes theproduction of DMSP by coral and coralsymbionts?
Answer: A negative feedback mechanism thatreverses the environmental change
Q: Which of the following best describes the effectof temperature on corals’ ability to produceDMSP as shown in Figure 1 ?
Answer: Both juvenile and adult corals produce lessDMSP at 27°C than at 32°C
Q: Which of the following best describes thedifference between the total amount of DMSPproduced by adults compared to juveniles at thestart of the 32°C trial?
Answer: Adult corals produced 5 times more DMSP than juveniles produced.
Q: In addition to the effect of temperature onDMSP produced by corals and their symbionts,which of the following relationships is alsobeing considered in this experiment?
Answer: Effect of additional DMSP produced bysymbionts and the corals’ age
Q: Which of the following best describes thescientists’ findings concerning the density ofsymbionts presented in Figure 2 ?
Answer: The symbiont density at 32°C wasdifferent from the density at 27°C ondays 5 and 10 of the experiment
Q: Which of the following best explains the resultof adult corals being exposed to elevatedtemperatures for extended periods?
Answer: They are able to obtain less energy fromtheir symbionts because the algae havebeen expelled
Q: A particular gene has two alleles, a dominantallele A and a recessive allele a. The frequencyof allele A is 0.55. If the population is inHardy-Weinberg equilibrium with respect to thegene, then what is the expected frequency ofgenotype Aa ?
Answer: 0.495
Q: Based on the codon chart above, which of thefollowing amino acid changes is most likelyfound in the mutated protein?
Answer: Glu → Val
Q: Figure 1 shows the inheritance of a particulargenetic condition in three generations of onefamily. Which of the following best explains theobserved pattern of inheritance?
Answer: The condition is passed from mothers tooffspring via a mitochondrial gene
Q: Oncogenes are genes that can cause tumorformation as a result of a particular mutation.Which of the following potential therapieswould be most effective at preventing theexpression of an oncogene?
Answer: Introducing a chemical that binds totranscription factors associated with theoncogene’s promoter
Q: Ultraviolet (UV) radiation can damage DNA bybreaking weak bonds. Which of the followingbest explains how this occurs?
Answer: UV radiation disrupts the double helixstructure by breaking the hydrogen bondsbetween the nitrogenous base pairs
Q: Based on the data in the table, which of the following lizard species are most closely related?
Answer: Species E and species D
Q: Figure 1 shows a model of the endocrinesignaling pathway that regulates ovulation.Which of the following observations wouldprovide evidence of a positive feedbackmechanism in this system?
Answer: Estrogen from the ovaries stimulates thehypothalamus and anterior pituitary tosecrete more GnRH, LH, and FSH
Q: In which of the following tubes did the greatestreduction of DCPIP occur after 60 minutes?
Answer: Tube 2
Q: Which of the following claims is best supportedby the experimental results?
Answer: Light is required for the electron transportchain to transfer electrons
Q: Which of the following best explains howDCMU affected the reaction?
Answer: DCMU acts as an inhibitor to themovement of electrons within the lightreaction of photosynthesis
Q: Which of the following best justifies the use oftube 2 as a control treatment?
Answer: It was a positive control for measuring theeffect of DCMU on the reaction
Q: A scientist designed an experiment to test anartificial membrane that mimics thephospholipid bilayer of a cell.The scientist built a tube that was divided by anartificial membrane and filled with distilledwater. The scientist put a known amount of aprotein into the water on one side of themembrane. After some time, the scientistmeasured the concentration of the protein oneither side of the membrane but found that therehad been no change.Which of the following experimental changeswould allow the scientist to observe transport ofa solute across the artificial membrane?
Answer: Use a small, nonpolar solute instead of aprotein
Q: Which of the following best illustrates the flowof information required for the synthesis ofproteins encoded in the genome of a retrovirus?
Answer: RNA–>DNA–>RNA–>Protein
Q: Which of the following best describes theprocess by which gas from the atmosphere isobtained by plants and used to build lipids?
Answer: Gas is directly obtained by plants as part ofthe carbon cycle
Q: Which of the following best explains how thephospholipid bilayer of a transport vesiclecontributes to cellular functions?
Answer: The phospholipid bilayer allows the vesicleto fuse with the Golgi apparatus and theplasma membrane, allowing theexocytosis of proteins
Q: The diploid number of chromosomes in the cellof a domesticated dog is 78. Which of thefollowing options includes the correct number ofchromosomes in a cell after each cellular process(G2 checkpoint, meiosis, and fertilization,respectively)?
Answer: After G2 checkpoint: 78, After Meiosis: 39, After Fertilization: 78
Q: Based on the data in the table, which of the following best explains the effects of rotenone on cellularrespiration?
Answer: Treated cells are not able to break down NADH because certain enzymes of the electron transport chain are inhibited
Q: Which of the following best explains whytriploid bananas do not produce seeds?
Answer: The production of gametes is disruptedbecause of unequal pairing ofhomologous chromosomes duringmeiosis
Q: Which of the following best explains why thepolymerase from the species T. aquaticus isoften used for PCR ?
Answer: T. aquaticus polymerase does not denatureat high temperatures
Q: A researcher is studying two different species.Which of the following sets of observationswould best support the claim that the twospecies have structural similarities as a result ofconvergent evolution?
Answer: Genetic similarity: low, Function of structure: same, Form of structure: different
Q: Based on the cladogram, which of the followingare the traits shared between ferns and pines?
Answer: Embryo and xylem only
Q: The researchers performed a chi-square analysis to test their hypothesis. Assuming the researchers use asignificance level of 0.05, which of the following is closest to the critical value the researchers should use inthe chi-square analysis?
Answer: 3.84
Q: Which of the following best describes whathappened to the otter population between 1750and 1850 ?
Answer: The population lost genetic diversity as aresult of a bottleneck effect
Q: Based on the information provided in thepassage, which of the following best describesthe effect of harmful algal blooms on otterpopulations?
Answer: They are a density-independent factor thatnegatively affects the otter populationregardless of its size
Q: As otters were removed during the huntingyears, there was a large decrease in the catchesof fish species from the eelgrass habitats. Whichof the following best explains why this decreasehappened?
Answer: Otters are a keystone species, so theirdisappearance from the area resulted inthe collapse of an entire community
Q: Climate change could affect the ecosystem ofthe Elkhorn Slough in many ways. From theinformation provided, which of the followingpredictions about the direct, local effects ofclimate change is most likely?
Answer: Ocean warming will favor populationgrowth of nonnative species as theirhabitats shift northward
Q: Based on the information, an increase in the seaslug population would most likely be directlyrelated to which of the following?
Answer: A decrease in the crab population
Q: Many fish species, such as fathead minnows,release a pheromone when their skin cells aredamaged. Researchers placed pike, a predator offathead minnows, in a choice chamber andreleased the minnow pheromone at one end ofthe chamber. The researchers observed that thepike oriented themselves toward the end of thechamber where the pheromone was released.Which of the following questions will best guidea follow-up investigation about the role ofpheromones in locating prey?
Answer: How do pike determine that the fatheadminnow pheromone is present in thewater?
Q: Which of the following best explains why acell’s plasma membrane is composed of twolayers of phospholipids rather than just a singlelayer?
Answer: Having two oppositely oriented layers ofphospholipids allows only the hydrophilicheads to interact with water inside andoutside of the cell
Q: Based on the data, which type of cell would bebest suited for the lining the alveoli of the lungs,where diffusion of carbon dioxide and oxygenmust occur very rapidly?
Answer: Simple squamous cells
Q: Which of the following best explains how theextensive folding of the inner mitochondrialmembrane benefits a eukaryotic cell?
Answer: It increases the area available for proteinsinvolved in energy transfer
Q: Some green sea turtle females deposit their eggsin nests that are dug on warm, tropical beaches.Researchers have studied the effects oftemperature on the hatching rate and theproportion of female to male hatchlingsproduced at different average nest temperaturesin Suriname (Figure 1). At temperatures below23°C or above 33°C, the eggs do not develop.Which of the following best describes the resultsshown in Figure 1 ?
Answer: Warmer nests produce more female seaturtles than do cooler nests
Q: Which of the following describes a scenario thatwould result in the phenotypic change shown inthe graph?
Answer: House sparrows that laysmaller-than-average clutches of eggsproduce fewer viable offspring, whilelarger-than-average clutches of eggs resultin malnourished chicks that have a highermortality rate
Q: Which of the following best explains the mostlikely method by which this antitumor drugworks?
Answer: Trabectedin interferes with the duplication of DNA during interphase and thus prevents cancer cells from passing the G checkpoint
Q: Based on the data in Figure 1, which of thefollowing best describes the inheritance patternof Friedreich’s ataxia?
Answer: Autosomal recessive
Q: The probability that individual III-5 willdevelop Friedreich’s ataxia is closest to which ofthe following?
Answer: 25%
Q: Which of the following statements best describesthe results seen in Figure 2 ?
Answer: Individuals III-2 and III-3 carry twodifferent alleles of the FXN gene, amutant allele and a wild-type allele.Individual IV-1 inherited two copies ofthe mutant allele
Q: Which of the following best describes the mostlikely effect of the formation of a triplex DNAstructure (Figure 3) on the synthesis of thefrataxin protein?
Answer: RNA polymerase is prevented frombinding to the DNA, resulting in adecrease in frataxin mRNA transcription
Q: Which of the following types of bonds is mostlikely responsible for the unusual base pairingshown in Figure 3 that results in the formation ofa triplex DNA structure?
Answer: Hydrogen
Q: Which of the following values is closest to thechi-square value the scientist calculated?
Answer: 23.1
Q: Which of the following research questions would best guide an investigation of the link between the structureof the signaling molecules and the evolution of quorum sensing?
Answer: Did these species evolve from a common ancestor that used a similar signaling molecule?
Q: Carbon dioxide most likely enters a cell throughwhich of the following processes?
Answer: Simple diffusion through the membrane
Q: In pea seeds, yellow color (Y ) is dominant togreen color (y), and a round shape (R) isdominant to a wrinkled shape (r). A dihybridcross between a true-breeding plant with yellow,round seeds (YYRR) and a true-breeding plantwith green, wrinkled seeds (yyrr) results in anF1 generation of plants with yellow, roundseeds. Crossing two F1 plants produces an F2generation with approximately nine times asmany plants with yellow, round seeds as plantswith green, wrinkled seeds.Which of the following best explains theseresults?
Answer: The genes for seed color and seed shapeassort independently