AP Bio Practice Exam 1 With Complete Questions And Answers

Humans produce sweat as a cooling mechanism to maintain a stable internal temperature. Which of the following best explains how the properties of water contribute to this physiological process? - ANSWER The high heat of vaporization of water allows the body to remove excess heat through a phase change of water from liquid to gas A student placed a semipermeable membrane inside a U-shaped channel with two chambers, as shown. The membrane permits the movement of water but not salt. The student wants to vary the rate of osmosis that occurs across the membrane. Which of the following experimental designs will result in the fastest net rate of water movement into chamber A? - ANSWER Placing salt water in chamber A and distilled water in chamber B Which of the following best describes the role of water in photosynthesis? - ANSWER Water molecules donate electrons to the electron transport chain What evolutionary advantage does compartmentalization of core metabolic processes offer eukaryotes? - ANSWER Evolution of a nucleus in eukaryotes separates the processes of transcription and translation and they can be regulated separately Which of the following best describes the cellular location where pyruvate dehydrogenase is most likely active? - ANSWER The mitochondrial matrix The maximum production rate of acetyl-CoA under condition 1 is closest to which of the following? - ANSWER 1 micromole/sec Which of the following observations provides the best evidence that acetyl-CoA negatively regulates pyruvate dehydrogenase activity? - ANSWER The rate of the pyruvate dehydrogenase-catalyzed reaction is slower in the presence of a higher concentration of acetyl-CoA Pyruvate dehydrogenase deficiency is a genetic disease most commonly linked to a mutation in the a -subunit of the mitochondrial enzyme that causes the enzyme to cease functioning. As a result of the mutation, affected individuals build up dangerous amounts of lactic acid. Which of the following best explains the buildup of lactic acid in individuals with the mutation? - ANSWER Cells undergo fermentation because pyruvate cannot be metabolized to proceed into the Krebs cycle The diagram shows how water can adhere to the xylem in the stems of plants, which contributes to water movement in the plant. Which of the following best explains how water is able to move upward from the roots of a plant, through its xylem in the stem, and out to the leaves? - ANSWER Water and the xylem are both polar. Water molecules have the ability to form hydrogen bonds with each other and with the walls of the xylem Protein X activates gene expression only in cells exposed to a specific signaling molecule. In a study, researchers determined the intracellular location of Protein X in cultured cells both before and after exposing the cells to the signaling molecule. The results of the study are shown in the diagram - ANSWER Protein X is a transcription factor The hormone prolactin has varying effects in many different animal species. All vertebrates produce prolactin, which is involved in signal transduction pathways. In mammals, prolactin stimulates the production of milk in mammary glands. In fish, prolactin plays an important role in osmoregulation. In birds, prolactin is involved in lipid metabolism. Which of the following best explains the presence of prolactin in various vertebrate species? - ANSWER Prolactin is a homologous hormone because it has a common origin but different functions in various species Which of the following best describes the production of DMSP by coral and coral symbionts? - ANSWER A negative feedback mechanism that reverses the environmental change Which of the following best describes the effect of temperature on corals' ability to produce DMSP as shown in Figure 1 ? - ANSWER Both juvenile and adult corals produce less DMSP at 27°C than at 32°C Which of the following best describes the difference between the total amount of DMSP produced by adults compared to juveniles at the start of the 32°C trial? - ANSWER Adult corals produced 5 times more DMSP than juveniles produced In addition to the effect of temperature on DMSP produced by corals and their symbionts, which of the following relationships is also being considered in this experiment? - ANSWER Effect of additional DMSP produced by symbionts and the corals' age Which of the following best describes the scientists' findings concerning the density of symbionts presented in Figure 2 ? - ANSWER The symbiont density at 32°C was different from the density at 27°C on days 5 and 10 of the experiment Which of the following best explains the result of adult corals being exposed to elevated temperatures for extended periods? - ANSWER They are able to obtain less energy from their symbionts because the algae have been expelled A particular gene has two alleles, a dominant allele A and a recessive allele a. The frequency of allele A is 0.55. If the population is in Hardy-Weinberg equilibrium with respect to the gene, then what is the expected frequency of genotype Aa ? - ANSWER 0.495 Based on the codon chart above, which of the following amino acid changes is most likely found in the mutated protein? - ANSWER Glu → Val Figure 1 shows the inheritance of a particular genetic condition in three generations of one family. Which of the following best explains the observed pattern of inheritance? - ANSWER The condition is passed from mothers to offspring via a mitochondrial gene Oncogenes are genes that can cause tumor formation as a result of a particular mutation. Which of the following potential therapies would be most effective at preventing the expression of an oncogene? - ANSWER Introducing a chemical that binds to transcription factors associated with the oncogene's promoter Ultraviolet (UV) radiation can damage DNA by breaking weak bonds. Which of the following best explains how this occurs? - ANSWER UV radiation disrupts the double helix structure by breaking the hydrogen bonds between the nitrogenous base pairs Based on the data in the table, which of the following lizard species are most closely related? - ANSWER Species E and species D Figure 1 shows a model of the endocrine signaling pathway that regulates ovulation. Which of the following observations would provide evidence of a positive feedback mechanism in this system? - ANSWER Estrogen from the ovaries stimulates the hypothalamus and anterior pituitary to secrete more GnRH, LH, and FSH In which of the following tubes did the greatest reduction of DCPIP occur after 60 minutes? - ANSWER Tube 2 Which of the following claims is best supported by the experimental results? - ANSWER Light is required for the electron transport chain to transfer electrons Which of the following best explains how DCMU affected the reaction? - ANSWER DCMU acts as an inhibitor to the movement of electrons within the light reaction of photosynthesis Which of the following best justifies the use of tube 2 as a control treatment? - ANSWER It was a positive control for measuring the effect of DCMU on the reaction A scientist designed an experiment to test an artificial membrane that mimics the phospholipid bilayer of a cell. The scientist built a tube that was divided by an artificial membrane and filled with distilled water. The scientist put a known amount of a protein into the water on one side of the membrane. After some time, the scientist measured the concentration of the protein on either side of the membrane but found that there had been no change. Which of the following experimental changes would allow the scientist to observe transport of a solute across the artificial membrane? - ANSWER Use a small, nonpolar solute instead of a protein Which of the following best illustrates the flow of information required for the synthesis of proteins encoded in the genome of a retrovirus? - ANSWER RNA-->DNA-->RNA-->Protein Which of the following best describes the process by which gas from the atmosphere is obtained by plants and used to build lipids? - ANSWER Gas is directly obtained by plants as part of the carbon cycle Which of the following best explains how the phospholipid bilayer of a transport vesicle contributes to cellular functions? - ANSWER The phospholipid bilayer allows the vesicle to fuse with the Golgi apparatus and the plasma membrane, allowing the exocytosis of proteins The diploid number of chromosomes in the cell of a domesticated dog is 78. Which of the following options includes the correct number of chromosomes in a cell after each cellular process (G2 checkpoint, meiosis, and fertilization, respectively)? - ANSWER After G2 checkpoint: 78, After Meiosis: 39, After Fertilization: 78 Based on the data in the table, which of the following best explains the effects of rotenone on cellular respiration? - ANSWER Treated cells are not able to break down NADH because certain enzymes of the electron transport chain are inhibited Which of the following best explains why triploid bananas do not produce seeds? - ANSWER The production of gametes is disrupted because of unequal pairing of homologous chromosomes during meiosis Which of the following best explains why the polymerase from the species T. aquaticus is often used for PCR ? - ANSWER T. aquaticus polymerase does not denature at high temperatures A researcher is studying two different species. Which of the following sets of observations would best support the claim that the two species have structural similarities as a result of convergent evolution? - ANSWER Genetic similarity: low, Function of structure: same, Form of structure: different Based on the cladogram, which of the following are the traits shared between ferns and pines? - ANSWER Embryo and xylem only The researchers performed a chi-square analysis to test their hypothesis. Assuming the researchers use a significance level of 0.05, which of the following is closest to the critical value the researchers should use in the chi-square analysis? - ANSWER 5.99 Which of the following best describes what happened to the otter population between 1750 and 1850 ? - ANSWER The population lost genetic diversity as a result of a bottleneck effect Based on the information provided in the passage, which of the following best describes the effect of harmful algal blooms on otter populations? - ANSWER They are a density-independent factor that negatively affects the otter population regardless of its size As otters were removed during the hunting years, there was a large decrease in the catches of fish species from the eelgrass habitats. Which of the following best explains why this decrease happened? - ANSWER Otters are a keystone species, so their disappearance from the area resulted in the collapse of an entire community Climate change could affect the ecosystem of the Elkhorn Slough in many ways. From the information provided, which of the following predictions about the direct, local effects of climate change is most likely? - ANSWER Ocean warming will favor population growth of nonnative species as their habitats shift northward Based on the information, an increase in the sea slug population would most likely be directly related to which of the following? - ANSWER A decrease in the crab population Many fish species, such as fathead minnows, release a pheromone when their skin cells are damaged. Researchers placed pike, a predator of fathead minnows, in a choice chamber and released the minnow pheromone at one end of the chamber. The researchers observed that the pike oriented themselves toward the end of the chamber where the pheromone was released. Which of the following questions will best guide a follow-up investigation about the role of pheromones in locating prey? - ANSWER How do pike determine that the fathead minnow pheromone is present in the water? Which of the following best explains why a cell's plasma membrane is composed of two layers of phospholipids rather than just a single layer? - ANSWER Having two oppositely oriented layers of phospholipids allows only the hydrophilic heads to interact with water inside and outside of the cell Based on the data, which type of cell would be best suited for the lining the alveoli of the lungs, where diffusion of carbon dioxide and oxygen must occur very rapidly? - ANSWER Simple squamous cells Which of the following best explains how the extensive folding of the inner mitochondrial membrane benefits a eukaryotic cell? - ANSWER It increases the area available for proteins involved in energy transfer Some green sea turtle females deposit their eggs in nests that are dug on warm, tropical beaches. Researchers have studied the effects of temperature on the hatching rate and the proportion of female to male hatchlings produced at different average nest temperatures in Suriname (Figure 1). At temperatures below 23°C or above 33°C, the eggs do not develop. Which of the following best describes the results shown in Figure 1 ? - ANSWER Warmer nests produce more female sea turtles than do cooler nests Which of the following describes a scenario that would result in the phenotypic change shown in the graph? - ANSWER House sparrows that lay smaller-than-average clutches of eggs