ap bio exam
Process in which sugar is oxidized to pyruvic acid
(A) Glysolysis
Process in which CO2, is released as a by-product of oxidation-reduction reactions
(B) Krebs cycle (citric acid cycle)
Process in which carbon from CO2 is incorporated into organic molecules
(C) Calvin cycle (light-independent reactions of photosynthesis)
Process in which O2 is released as a by-product of oxidation-reduction reactions
(D) Light-dependent reactions of photosynthesis
Process found in both photosynthesis and cellular respiration
(E) Chemiosmosis
A particular genetic disorder is associated with a single gene with two alleles. Individuals with two recessive alleles are affected. The prevalence of the disorder is 11 in 6,6006,600. Assuming the population is in Hardy-Weinberg equilibrium, which of the following is closest to the frequency of carriers in the general population?
0.02430
A moth's color is controlled by two alleles, G and g, at a single locus. G (gray) is dominant to g (white). A large population of moths was studied, and the frequency of the G allele in the population over time was documented, as shown in the figure below. In 1980 a random sample of 2,000 pupae was collected and moths were allowed to emerge. Assuming that the population was in Hardy-Weinberg equilibrium for the G locus, what was the frequency of allele G in the gray moths that emerged in 1980?
0.50
A moth's color is controlled by two alleles, G and g, at a single locus. G (gray) is dominant to g (white). A large population of moths was studied, and the frequency of the G allele in the population over time was documented, as shown in the figure below. In 1980 a random sample of 2,000 pupae was collected and moths were allowed to emerge. Assuming that the population was in Hardy-Weinberg equilibrium for the G locus, what percentage of moths in the natural population was white in 1962 ?
20%
Within a forest ecosystem, there is a large amount of diversity among members of a warbler species. Of the following stages of meiosis illustrated for a typical cell, which contributes most to diversity among the warblers?
4 x in the middle
The following questions refer to the following DNA strand and table of codons. The mRNA transcribed from the DNA would read
5' AUC AAG UUU GGC GCA UUG UAA 3'
The probability that Matthew and Jane's first child will be an achondroplastic dwarf is
50%
The graph above shows the distribution of beak depth in a finch population that had been living on an island under conditions of normal rainfall. During a subsequent drought, the small seeds normally eaten by the finches were less available. Most of the available seeds were large seeds that could be eaten most easily by finches with deep beaks. Which of the following graphs best predicts the distribution of beak depth in the finch population after several years of drought?
6 to 14 increasing
Which of the following best represents the DNA of the two daughter cells produced when a bacterial cell with this particular mismatch replicates its DNA and divides?
A T : mutant // G C: Normal
A biologist spent many years researching the rate of evolutionary change in the finch populations of a group of islands. It was determined that the average beak size (both length and mass) of finches in a certain population increased dramatically during an intense drought between 1981 and 1987. During the drought, there was a reduction in the number of plants producing thin-walled seeds. Which of the following best describes the mechanism behind the change in beak size in the finch population?
A change in gene frequencies in the finch population due to selective pressure from the environmental change
What is the most likely explanation for the change in the slope of the line between 3 and 5 minutes?
A large amount of the substrate had been consumed.
The energy required to run the Calvin cycle reactions of photosynthesis comes from which two substances produced during the light-dependent reactions?
ATP and NADPH
A researcher claims that the synthesis of ATPATP from ADPADP and inorganic phosphate (Pi)(Pi) is essential to cellular function. Which of the following statements best helps justify the researcher's claim?
ATP hydrolysis is an energy-releasing reaction that is often coupled with reactions that require an input of energy.
The results of the experiment can be used as evidence in support of which of the following scientific claims about mitochondrial activity?
ATP production in mitochondria requires a hydrogen ion gradient that favors movement of protons into the mitochondrial matrix.
Which of the following best describes the cause of the rapid increase in the number of mammalian species between 65 and 55 million years ago?
After the dinosaur extinction, many ecological niches became available, leading to the adaptive radiation of mammals.
Which of the following best explains the differences in flower color of the African violets in the greenhouse?
An enzyme responsible for flower color does not fold correctly in cooler temperatures, and the greenhouse is warmest in the center.
The processes illustrated in the models depicted above all result in which of the following?
An increase in genetic variation
Which of the following is probably the best explanation for the fact that Antarctic penguins cannot fly, although there is evidence that millions of years ago their ancestors could do so?
Ancestral penguins without large wings were better able to swim and feed in the water; therefore they passed their genes for shorter wing structure on to their offspring.
A researcher claims that only a portion of the light energy captured by green plants is available for growth and repair. Which of the following observations best helps justify the researcher's claim?
As light energy is converted to chemical energy by metabolic processes, some of the energy is lost as heat.
A researcher claims that increased atmospheric carbon dioxide levels cause increased growth rates in plants. Which of the following statements best supports the researcher's claim?
Atmospheric carbon dioxide is the raw material for photosynthesis, which plants rely on for producing sugars and other organic compounds.
The pedigree of a family with a history of a particular genetic disease is shown below. Squares represent males and circles represent females. Shaded symbols represent those who have the disease. Which of the following is the most likely mode of inheritance for the disease?
Autosomal recessive
In the pedigree above, circles represent females, squares represent males, and shaded figures represent individuals expressing a specific trait. The expression of this trait is most likely due to which of the following?
Autosomal recessive inheritance
Butterflies of the genus Colias live in the Rocky Mountains, where they experience a wide range of temperatures. Different variants of a particular glycolytic enzyme in the flight muscles are optimally active at different temperatures. Within the same population, some individual butterflies fly most effectively at 29°C , while others fly most effectively at 40°C. Still others can be equally active at both temperatures. Which of the following claims is most consistent with the observed butterfly behavior?
Butterflies that express two variants of the enzyme are active over a greater range of temperature.
In cross II, the genotype of the dark, short-haired parent is
CcBb
Which of the following rows of data listed in table 1 best supports the possibility of a common ancestor for the organisms listed there?
Cell wall composed of cellulose
In which of the following would there NOT be a change in the amino acid sequence of the peptide coded for by this DNA?
Changing 3' AAA 5' to read 3' AAG 5'
Ciprofloxacin is given as an antibiotic to healthy livestock to promote efficient weight gain. Strains of the bacterium Campylobacter jejuni naturally colonize the digestive tracts of livestock, and the C. jejuni can be transferred to people through the handling and consumption of contaminated meat. People infected with C. jejuni also are treated with ciprofloxacin. Which of the following is the most likely consequence of adding ciprofloxacin to animal feed?
Ciprofloxacin-resistant strains of C. jejuni will have a selective advantage in the digestive tracts of livestock, increasing the risk of serious infections in people.
Which of the following statements best predicts the effect of increasing the concentration of substrate (ethyl alcohol), while keeping the concentration of the inhibitor (methyl alcohol) constant?
Competitive inhibition will decrease because the proportion of the active sites occupied by substrate will increase.
Which of the following correctly explains where DNADNA replication will begin on the strand oriented 5'→3'5′→3′, reading from left to right?
DNADNA replication will be initiated immediately to the left of the RNARNA, since DNADNA polymerase requires an RNARNA primer.
The figures can best assist in answering which of the following questions?
Do electron transport chains create a gradient so that ATP synthase can generate ATP molecules?
Which of the following questions can best be answered by the diagram?
Does the addition of an enzyme reduce the activation energy required for a reaction?
Which of the following statements best helps justify the researcher's claim by providing a relevant example?
E. coli bacteria reproduce in liquid media containing either glucose or galactose.
Table 1 shows the stage and number of cells and chromosomes per cell at the end of the stage in a 2n=242n=24 organism. Which of the following statements correctly describes the chromosomes in each daughter cell at the end of meiosis I
Each daughter cell contains 12 chromosomes, each composed of two chromatids. Each chromosome is one of a pair of homologous chromosomes from the parent cell, with the other homologue found in the other daughter cell.
Coenzyme that transfers electrons from the Krebs cycle to the mitochondrial electron-transport chain at a lower energy level than that of electrons entering at the beginning of the chain
FADH2
The table below describes the action of two genes involved in the regulation of nervous system development in the nematode C. elegans. Which of the following claims is best supported by the data?
Gene A promotes neuron development; gene B promotes programmed cell death in neuronal precursors.
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
Which of the following statements best helps explain the reaction specificity of hexokinase?
Glucose has the right shape and charge to cause hexokinase to undergo a structural change needed for catalysis, whereas water does not.
Experimental evidence shows that the process of glycolysis is present and virtually identical in organisms from all three domains, Archaea, Bacteria, and Eukarya. Which of the following hypotheses could be best supported by this evidence?
Glycolysis is a universal energy-releasing process and therefore suggests a common ancestor for all forms of life.
Which of the following best supports the claim that organisms of different domains share a common ancestor?
Glycolysis occurs in both prokaryotic cells and eukaryotic cells.
The O2 released during photosynthesis comes from
H2O
Which of the following statements about mitochondrial chemiosmosis is NOT true?
Heat energy is required to establish the electron transport chain.
Figure 1. Two possible arrangements of chromosomes during meiosis Which of the following questions about genetic diversity could most appropriately be answered by analysis of the model in Figure 1 ?
How does the independent assortment of the two sets of homologous chromosomes increase genetic diversity?
Based on Figure 1, which of the following best describes how the properties of water at an air-water interface enable an insect to walk on the water's surface?
Hydrogen bonds between molecules at the surface of the water provide surface tension, which allows the water surface to deform but not break under the insect.
Graphs representing enzymes sensitive to changes in pH include which of the following?
I only
Plates that have only ampicillin-resistant bacteria growing include which of the following?
IV only
A researcher placed a culture of cyanobacteria under green lights. Within a few weeks, the appearance of the cyanobacteria changed from green to red. The researcher claimed the color change in the culture was the result of an adaptation allowing greater photosynthesis. Which of the following provides the best reasoning to justify the researcher's claim?
In green light, more phycoerythrin molecules are produced, allowing more green light to be absorbed, thus increasing photosynthesis.
Which of the following conclusions is best supported by the data?
In pea seeds an increase in temperature results in an increase in oxygen consumption.
Which of the following statements provides the most reasonable prediction to account for the deviation from the expected results?
In sweet pea plants, the gene for flower color and the gene for pollen grain shape are genetically linked.
The Trp operon is a coordinately regulated group of genes (trpA-trpE) that are required for tryptophan biosynthesis in E. coli. Based on the figure above, which of the following correctly describes the regulation of the Trp operon?
In the presence of tryptophan, the repressor is active and binds to the Trp operator, preventing RNA polymerase from transcribing the operon.
Figure 1. Process occurring in a cell Which of the following correctly explains the process shown in Figure 1 ?
Initiation of transcription is occurring because a strand of RNA is being produced from a DNA template strand.
During prophase II replicated homologous chromosomes pair up and undergo synapsis. What testable question is generated regarding synapsis and genetic variability by Figure 1 ?
Is the distance between two gene loci related to crossover rate?
All of the following are true statements about meiosis in mammals EXCEPT:
It produces four genetically identical gametes.
Which of the following best predicts how the amino acid deletion will affect the structure of the CFTRCFTR protein?
It will affect the primary, secondary, and tertiary structures of the CFTRCFTR protein.
The claim that gene regulation results in differential gene expression and influences cellular products (albumin or crystalline) is best supported by evidence in which of the following statements?
Liver cells possess transcriptional activators that are different from those of lens cells.
Which of the following data sets is most likely to provide reliable information about the evolutionary relationships among these three snail species?
Location of fossils and shell orientation
Methicillin-resistant Staphylococcus aureus (MRSA) can be a serious threat to human health. There is evidence that S. aureus infections are common in hospitals and that MRSA have become resistant to other antibiotics besides methicillin. This suggests that the rapid evolution of resistance in the bacteria poses a serious public-health challenge. Which of the following best explains the ability of MRSA to evade existing drug therapies?
MRSA exchange genetic material with other antibiotic-resistant bacteria, which can spread resistance in the S. aureus population.
Both mitosis and meiosis begin with a parent cell that is diploid. Which of the following best describes how mitosis and meiosis result in daughter cells with different numbers of chromosomes?
Mitosis produces two identical diploid daughter cells after one round of division. Meiosis produces four haploid daughter cells after two rounds of division.
Figure 1. Gel electrophoresis of three prepared samples Which of the following statements best explains the pattern seen on the gel with regard to the size and charge of molecules AA and BB?
Molecules AA and BB are negatively charged, and molecule AA is smaller than molecule BB.
Which of the following occurs in all species of living organisms and may lead to an increase in genetic variation?
Mutations in the genome
An intermediate electron acceptor for oxidations that occur in both glycolysis and in Krebs cycle reactions
NAD+
Which of the following statements best explains why there are fewer colonies on plate IV than on plate III?
Not all E. coli cells are successfully transformed.
Which of the following best describes a characteristic of DNA that makes it useful as hereditary material?
Nucleotide bases in one strand can only be paired with specific bases in the other strand.
Which organism would the researchers most likely predict to be the most distantly related to eukaryotes?
Organism I
Group IV of the cladogram most likely includes which of the following species?
P and S only
What most likely causes the trends in oxygen concentration shown in the graph above?
Photosynthesis produces more oxygen than is consumed by respiration during the day.
Which of the following statements best explains the structure and importance of plasmids to prokaryotes?
Plasmids are circular, double-stranded DNADNA molecules that provide genes that may aid in survival of the prokaryotic cell.
Which of the following statements best explains how protein X regulates gene expression?
Protein X is responsible for activating transcription of some genes but not others.
A scientist is attempting to provide support for the hypothesis that RNARNA was the first genetic material. Which of the following would be a workable alternate hypothesis?
RNARNA can be observed to self-replicate without the assistance of proteins, while DNADNA always requires protein-based enzymes to replicate.
Which of the following best explains how continuity of genetic information in cells is ensured across generations?
Replication uses a parental strand of DNADNA as a template to create a new strand of DNADNA.
Which of the following best explains how the prokaryotic expression of a metabolic protein can be regulated when the protein is already present at a high concentration?
Repressor proteins can be activated and bind to regulatory sequences to block transcription.
The data above represent the results of three different crosses involving the inheritance of a gene that determines whether a certain organism is blue or white. Which of the following best explains the mechanism of inheritance of the gene?
The allele for blue is an X-linked dominant allele because there are no blue male offspring in cross 2.
A current challenge for doctors involves the bacterial strain Clostridioides difficile, which no longer responds to traditional antibiotic treatments. Which of the following best explains why this particular strain of bacteria is resistant to antibiotic treatment?
The bacteria have high genetic variability and high reproductive rates.
Which of the following statements about glucose, galactose, and fructose is most likely true?
The carbohydrates have different properties because they have different arrangements of carbon, hydrogen, and oxygen atoms.
Which of the following best describes the effect of a greater number of cysteine amino acids on the stability of the proteins?
The change leads to increased protein stability because of an increased number of S-SS-S bonds in the tertiary structure of the proteins.
Which of the following occurs during mitosis but not during meiosis I ?
The chromatids of each chromosome are separated.
The student calculates a chi-square value of 0.36. Which of the following statements best completes the student's chi-square goodness-of-fit test?
The critical value is 3.84, and the student cannot reject the null hypothesis.
Some scientists claim that amphibians are currently experiencing a period of mass extinction. Which of the following should be included in an alternative hypothesis that would best support this claim?
The current extinction rate of amphibians compared with the background rate of extinction as determined by the fossil record
Which of the following is most likely responsible for the seasonal change in coat color?
The decrease in the amount of daylight in winter causes a change in gene expression, which results in the foxes growing a lighter-appearing coat.
The diagram above depicts a karyotype of an individual human. Which of the following statements concerning the karyotype in the diagram is true?
The diagram illustrates the results of nondisjunction during gamete formation.
Which of the following best describes the likely mode of inheritance for the eye-color gene?
The eye-color gene is likely autosomal because males and females have similar phenotype ratios.
In an experiment, 100 mice were released into a field to which no other mice had access. Immediately after their release, a representative sample of mice was captured, their fur color was recorded, and they were returned to the field. After twenty years, a representative sample of mice was captured and the distribution of fur color was again recorded. Which of the following could best explain the change in fur color distribution, as shown in the table above?
The field was primarily composed of light-colored soil and little vegetation, affording gray mice protection from predators.
In eastern gray squirrels, Sciurus carolinensis, the allele for black fur (B)(B) is dominant to the allele for gray fur (b)(b). In a particular population of gray squirrels, 64% have black fur and 36% have gray fur. A researcher calculated the allelic frequencies to be B=0.4B=0.4 and b=0.6b=0.6. Five years later, the researcher returned to the location and determined the allelic frequencies within the squirrel population to be B=0.6B=0.6 and b=0.4b=0.4. Which of the following could best explain the increase in the frequency of the BB allele in the population after five years?
The frequency of the BB allele increased due to the selective pressures of the environment.
Which of the following best explains how bacteria can be genetically engineered to produce a desired antigen?
The gene coding for the antigen can be inserted into plasmids that can be used to transform the bacteria.
In pea seeds, yellow color (YY) is dominant to green color (yy), and a round shape (RR) is dominant to a wrinkled shape (rr). A dihybrid cross between a true-breeding plant with yellow, round seeds (YYRR)(YYRR) and a true-breeding plant with green, wrinkled seeds (yyrryyrr) results in an F1F1 generation of plants with yellow, round seeds. Crossing two F1F1 plants produces an F2F2 generation with approximately nine times as many 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.
Which of the following best describes why the disks rose to the surface faster in the more concentrated hydrogen peroxide solutions?
The higher substrate concentrations in the more concentrated solutions speeded the reaction.
Which of the following best explains why ligase is required for DNADNA replication?
The lagging strand cannot be replicated continuously, and ligase is needed to join the fragments.
In humans, red-green color blindness is a sex-linked recessive trait. If a man and a woman produce a color-blind son, which of the following must be true?
The mother carries the allele for color blindness.
Which statement best helps explain the formation of the hydrogen bond represented in the figure?
The nitrogen has a partial negative charge, and the hydrogen attached to the oxygen has a partial positive charge.
The researchers calculate a chi-square value of 4.6 and choose a significance level of p=0.05p=0.05. Which of the following statements best completes the chi-square goodness-of-fit test?
The null hypothesis cannot be rejected because the chi-square value is less than the critical value.
All of the following are examples of prezygotic genetic isolating mechanisms EXCEPT:
The progeny of a cross between two different lizard species fail to develop properly.
The following the DNA sequence is a small part of the coding (nontemplate) strand from the open reading frame of β-hemoglobin gene. Given the codon chart listed below, what would be the effect of a mutation that deletes the G at the beginning of the DNA sequence?
The reading frame of the sequence would shift, causing a change in the amino acid sequence after that point.
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?
The reduced population will likely have allelic frequencies that are different from the initial population.
Sugar gliders and Northern flying squirrels are mammals that have many morphological similarities despite being genetically different. Both are nocturnal and have large eyes to help them see in the dark. Both live in trees and have flaps of skin connecting their front and back legs, and when their front and back legs are extended, the flaps allow the animals to glide from one tree branch to another. Sugar gliders are native to Australia, and Northern flying squirrels are native to North America. Which of the following best explains the morphological similarities between these two species?
The similarities between the species evolved independently as a result of similar selective pressures in each species' environment.
The different fruit preferences of the two fly populations will most likely have which of the following effects?
The single fly species will evolve into two distinct species because of the lack of gene flow between the two populations.
Figure 1. Protein synthesis in a prokaryotic cell Which of the following best describes a characteristic of the process shown in Figure 1 that is unique to prokaryotes?
The translation of the mRNAmRNA is occurring while the mRNAmRNA is still being transcribed.
In humans, one allele of the APOEAPOE gene, called APOE-ε2APOE-ε2, can result in a high tolerance of cholesterol. Cholesterol is a vital substance for humans but may lead to heart disease in an older adult with a history of high cholesterol diets. High cholesterol diets are becoming more prevalent in the United States. Currently only about 2% of humans carry the APOE-ε2APOE-ε2 allele. Which of the following states a valid null hypothesis about the future distribution of APOEAPOE alleles in future generations in the United States?
The variant protects an individual from a condition that is only common among humans beyond reproductive age, so the frequency of the allele will likely not change much in the future because it is not influenced by natural selection.
Which of the following best describes the functionof the coenzymes NAD+ and FAD in eukaryoticcellular respiration?
They accept electrons during oxidation-reductionreactions.
Which of the following best describes the cells that result from the process of meiosis in mammals?
They are genetically different from the parent cell.
Which of the following observations would provide the strongest evidence that two plants belong to different biological species?
They produce viable but sterile offspring.
Which of the following best describes the role of water in photosynthesis?
Water molecules donate electrons to the electron transport chain.
Over many years of a breeding program, a zoo has an established population of foxes that is well adapted for living in captivity. A representative sample of wild foxes from the neighboring forest was used to start the zoo population. A study was conducted to compare the behavior of the zoo fox population with the wild fox population in the neighboring forest. The behaviors of equal numbers of foxes from each population were assessed. Each fox's behavior was scored on a continuum from docile to aggressive based on its interaction with a trained behaviorist. The data is shown in Figure 1. Figure 1. Aggressive behavior in zoo and wild fox populations The phenotypic variation in behavior between the two populations can best be described as resulting from
artificial selection
Competition for food would probably be most severe between two
closely related species in similar niches
The reactions of glycolysis occur in the
cytosol
Analysis of DNA sequences from two individuals of the same species results in a greater estimate of genetic variability than does analysis of amino acid sequences from the same individuals because
different DNA sequences can code for the same amino acid
The table above shows derived characters for selected organisms. Based on the information in the table, which of the following cladograms best represents the evolutionary relationships among the organisms?
fish, amphibians, crocs, birds, mammals
In a small group of people living in a remote area, there is a high incidence of "blue skin", a condition that results from a variation in the structure of hemoglobin. All of the "blue-skinned" residents can trace their ancestry to one couple, who were among the original settlers of this region. The unusually high frequency of "blue skin" in the area is an example of
genetic drift
The genotypes of Matthew and Jane are best represented as
mat- aa// jane- Aa
Within the cell, many chemical reactions that, by themselves, require energy input (have a positive free-energy change) can occur because the reactions
may be coupled to the hydrolysis of ATP
The rate of the reaction could also be determined by
measuring the change in the amount of substrate
Which of the following best depicts the tertiary structures of the two proteins in water? The diagrams in the options are not drawn to the same scale as those in Figure 1 and Figure 2.
og protein: beads in a ball // mutated protein: beads in a ball with on bead on the outer rim
Lactose digestion in E. coli begins with its hydrolysis by the enzyme β-galactosidase. The gene encoding β-galactosidase, lacZ, is part of a coordinately regulated operon containing other genes required for lactose utilization. Which of the following figures correctly depicts the interactions at the lac operon when lactose is NOT being utilized? (The legend below defines the shapes of the molecules illustrated in the options.)
promoter: empty// operator: white u, nothing on top // lac z lac y lac a
The fossil record indicates that in some cases reasonably well-defined species appear suddenly and remain unchanged for a long time before they become extinct. This phenomenon is referred to as
punctuated equilibrium
The condition in which there are barriers to successful interbreeding between individuals of different species in the same community is referred to as
reproductive isolation