AP Biology - Practice MCQ

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?

0.495

The maximum production rate of acetyl-CoA under condition 1 is closest to which of the following?

1 micromole/sec

Which of the following values is closest to the chi-square value the scientist calculated?

23.1

The probability that individual III-5 will develop Friedreich's ataxia is closest to which of the following?

25%

The researchers performed a chi-square analysis to test the hypothesis. Assuming the researchers are using a significance level of 0.05, which of the following is closest to the critical value the researcher should use in the chi-square analysis?

3.84

Based on the information, an increase in the sea slug population would most likely be directly related to which of the following?

A decrease in the crab population

Which of the following best describes the production of DMSP by coral and coral symbionts?

A negative feedback mechanism that reverses the environmental change

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?

Adult corals produced 5 times more DMSP than juveniles produced

The diploid number of chromosomes in the cell of a domesticated dog is 78. Which of the following options includes the correct number if chromosomes in a cell after each cellular processes (G2 checkpoint, meiosis, and fertilization respectively)?

After G2 checkpoint: 78 After Meiosis: 39 After fertilization: 78

Based on the data in Figure 1, which of the following best describes the inheritance pattern of Friedreich's ataxia?

Autosomal recessive

Which of the following best describes the effect of temperature on corals' ability to produce DMSP as shown in Figure 1?

Both juvenile and adult corals produce less DMSP at 27° than at 32°

Pyruvate hydrogenase 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 acid. Which of the following best explains the buildup of lactic acid in individuals with the mutation?

Cells undergo fermentation because pyruvate cannot be metabolized to proceed into the Kreb's cycle

Which of the following best explains how DCMU affected the reaction?

DCMU acts as an inhibitor to the movement of electrons within the light reaction of photosynthesis

Which of the following research questions would best guide an investigation of the link between the structure of the signaling molecules and the evolution of quorum sensing?

Did these species evolve from a common ancestor that used a similar signaling molecule?

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?

Effect of additional DMSP produced by symbionts and the corals' age

Based on the cladogram, which of the following are the traits shared between ferns and pines?

Embryo and xylem only

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?

Estrogen from the ovaries stimulates the hypothalamus and anterior pituitary to secrete more GnRH, LH and FSH

What evolutionary advantage does compartmentalization of core metabolic processes offer eukaryotes?

Evolution of a nucleus in eukaryotes separate the processes of transcription and translation they can be regulated separately

Which of the following best describes the process by which gas from the atmosphere is obtained by plants and used to build lipids?

Gas is directly obtained by plants as part of the carbon cycle

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?

Genetic similarity: low Function of structure: same Form of structure: different

A particular genetic disorder results from a single change in the amino acid sequence coded for in a gene. Parts of the sequence in normal and mutated genes are shown below. Normal: TAC CTC GTG TGA GGT CTC Mutated: TAC CTC GTG TGA GGT CAC Based on the codon chart above, which of the following amino acid changes is most likely found in the mutated protein?

Glu -> Val

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?

Having two oppositely oriented layers of phospholipids allow only the hydrophilic heads to interact with water inside and outside of the cell

Which of the following describes a scenario that would result in the phenotypic change shown in the graph?

House sparrows that lay smaller than average clutches of eggs produce fewer viable offspring, while larger than average clutches of eggs result in malnourished chucks have a larger mortality rate

Which of the following questions will bestsellers guide a follow-up investigation about the role of pheromone in locating prey?

How do pike determine that the fathead minnow pheromone is present in the water?

Which of the following types of bonds is most likely responsible for the unusual base pairing shown in Figure 3 that results the formation of a triplex DNA structure?

Hydrogen

Which of the following statements best describes the results seen in Figure 2?

Individuals III-2 and III-3 carry two different alleles of the FXN gene, a mutant allele and a wild-type allele. Individual IV-1 inherited two copies of the mutant allele.

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?

Introducing a chemical that binds to transcription factors associated with the oncogene's promoter

Which of the following best explains how the extensive folding of the inner mitochondria membrane benefits a eukaryotic cell?

It increases the area available for proteins involved in energy transfer

Which of the following best justifies the use of tube 2 as a control treatment?

It was a positive control for measuring the effect of DCMU on the reaction

Which of the following claims is best supported by the experimental results?

Light is required for the electron transport chain to transfer electrons

Climate change could affect the ecosystem of the Elkhorn Slough in many ways. From the information provided, which of the following predictions about the erect, local effects of climate change is most likely?

Ocean warming will favor population growth of nonnative species as their habitats shift northward

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?

Otters are a keystone species, so their disappearances from the area resulted in the collapse of an entire community

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 changes will result in the fastest net rate of water movement into chamber A?

Placing salt water in chamber A and distilled water in chamber B

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?

Prolactin is a homologous hormone because it has a common origin but different functions in various species

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. Based on the results, which of the following best describes what Protein X is?

Protein X is a transcription factor

Which of the following best illustrates the flow of information required for the synthesis of proteins encoded in the genome of a retrovirus?

RNA -> DNA -> RNA -> Protein

Which of the following best describes the most likely effect of the formation of a triplex DNA structure on the synthesis of the frataxin protein?

RNA polymerase is prevented from binding to the DNA, resulting in a decrease in frataxin mRNA transcription

Carbon dioxide most likely enters a cell through which of the following processes?

Simple diffusion through the membrane

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?

Simple squamous cells

Scientists are interested in determining the evolution of seven lizard species on different islands of the Canary Island group. They isolated DNA from individuals of each species and sequenced the mitochondrial gene that encodes cytochrome b. The numbers of genetic differences between species are shown in the table below. Based on the data in the table, which of the following lizard species are most closely related?

Species E and species D

Which of the following best explains why the polymerase from the species T. aquatics is often used for PCR?

T. aquatics does not denature at high temperatures

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?

The condition is passed from mothers to offspring via a mitochondrial gene

In pea seeds, yellow color (Y) is dominant to green color (y), and a round shape (R) is dominant to wrinkled shape (r). A dihybrid criss between a true-breeding plant with yellow, round seeds (YYRR) and a true breeding plant with green, wrinkles seeds (yyrr) results in an F1 generation of plants with yellow, round seeds. Crossing two F1 plants produces an F2 generation with approximately nine times as man plants with yellow, round seeds as plants with green, wrinkled seeds. Which of the following best explains these results?

The genes for seed color and seed shape assort independently.

Humans produce sweat as a cooling mechanism. Which of the following best explains how the properties of water contribute to this physiological process?

The high heat of vaporization of water allows the body to remove excess heat through a phase change of water from a liquid to a gas

Which of the following best describes the cellular location where pyruvate dehydrogenase is most likely active?

The mitochondrial matrix

Which of the following best explains how the phospholipid bilayer of a transport vesicle contributes to cellular functions?

The phospholipid bilayer allows the vesicle to fuse with the Golgi apparatus and the plasma membrane, allowing the exocytosis of proteins

Which of the following best describes what happened to the otter population between 1750 and 1850?

The population lost genetic diversity as a result of a bottleneck effect

Which of the following best explains why triploid bananas do not produce seeds?

The production of gametes is disrupted because of unequal pairing of homologous chromosomes during meiosis

Which of the following observations provides the best evidence that acetyl-CoA negatively regulated pyruvate hydrogenase activity?

The rate of pyruvate hydrogenase-catalyzed reaction is slower in the presence of a higher concentration of acetyl-CoA

Which of the following best describes the scientists' findings concerning the density of symbionts presented in Figure 2?

The symbionts' density at 32° was different from the density at 27° 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?

They are able to obtain less energy from their symbionts because the algae have been expelled

Based on the information provided in the passage, which of the following best describes the effect of harmful algal blooms on other populations?

They are the density-independent factor that negatively affects the otter population regardless of its size

Which of the following best explains the most likely method by which this anti tumor drug works?

Trabectedin interferes with the duplication of DNA during interphase and thus prevents cancer cells from passing the G2 checkpoint

Based on the data in the table, which of the following best explains the effects of rotenone on cellular respiration?

Treated cells are not able to break down NADH because certain enzymes of the electron transport chain are inhibited

In which of the following tubes did the greatest reduction of DCPIP occur after 60 minutes?

Tube 2

Ultraviolet (UV) radiation can damage DNA by breaking weak bonds. Which of the following best explains how this occurs?

UV radiation disrupts the double helix structure by breaking the hydrogen bonds between the nitrogenous base pairs

Which of the following experimental changes would allow the scientist to observe transport of a solute across the artificial membrane?

Use a small, non polar solute instead of a protein

Which of the following best describes the results shown in Figure 1?

Warmer nests produce more female sea turtles than do cooler nests

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

Water and xylem are both polar. Water molecules have the ability to form hydrogen bonds with each other and with the walls of the xylem

Which of the following best describes the role of water in photosynthesis?

Water molecules donate electrons to the electron transport chain