AP Bio
In a classic experiment from the 1970s investigating gene expression, a solution containing equal amounts of rabbit a-hemoglobin mRNA and B-hemoglobin mRNA, which encode subunits of a protein found in red blood cells, was injected into newly fertilized frog eggs. The injected mRNA was not degraded during the course of the experiment. Tadpoles that developed from the injected eggs were dissected into two fragments, one containing predominantly the notochord, muscle tissue, and nerve tissue and the other containing predominantly the other tissue types. Equal amount of the total proteins were analyzed after separation by elecrophresis to identify the relative amounts of the different proteins in each sample. The thickness of the bands indicates the relative amounts of rabbit a-hemoglobin, rabbit B-hemoglobin, and frog tubulin (cytoskeletal protein that is expressed at relatively constant levels in all tissues) present in each tadpole sample. The experimental protocol and results are summarized in the figure below. Given that equal amounts of the different mRNAs were injected into fertilized frog eggs, which of the following conclusions is most consistent with the electrophoresis results? (A) B-hemoglobin mRNA is translated more efficiently than is a-hemoglobin mRNA (B) a-hemoglobin is present only in cells were B-hemoglobin is absent (C) a-hemoglobin MRNA is more stable than B-hemoglobin mRNA (D) Tubulin inhibits translation of hemoglobin mRNA
(A) B-hemoglobin mRNA is translated more efficiently than is a-hemoglobin mRNA
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?
(A) Graph that shows no change
In 1944 Avery, MacLeod, and McCarty performed transformation experiments using live, harmless bacteria and extracts from virulent bacteria treated with various enzymes. Which of the following enzymes were used and why? (A) Proteases and RNases to rule out protein and RNA as the transforming factors (B) Lipase (an enzyme that facilitates the breakdown of lipids) to rule out lipoproteins as the transforming factor (C) Kinase (an enzyme that facilitates transfer of a phosphate group from ATP to a substrate molecule) to show that transformation is phosphorylation dependent (D) ATPase to show that transformation is not dependent to ATP
(A) Proteases and RNases to rule out protein and RNA as the transforming factors
A new mutation that arose in one copy of gene X in a somatic cell resulted in the formation of a tumor. Which of the following pieces of evidence best describes how the new mutation directly caused the tumor? (A) Protein X normally stimulates cell division, and the mutation created an overactive version of protein X (B) Protein x normally activates a growth hormone receptor, and the mutation decreased the stability of protein X (C) Protein X normally prevents passage through the cell cycle, and the mutation created an overactive version of protein X (D) Protein X normally regulates gene expression, and the mutation created an underactive version of protein X that blocked the cell cycle
(A) Protein X normally stimulates cell division, and the mutation created an overactive version of protein X
The following figures display data collected while studying a family, some members of which have sickle-cell disease--a rare genetic disorder caused by a mutation in the hemoglobin beta gene (HBB). There are at least two alleles of the HBB gene: the HbA allele encodes wild-type hemoglobin and the HbS allele encodes the sickle-cell form of hemoglobin. Genetic testing provided insight into the inheritance pattern for sickle-cell disease. Figure 1. Pedigree of a family with affected individuals. Square represent males, circles represent females, shaded symbols represent individuals with sickle-cell disease. Figure 2. A portion of the DNA sequence from the wild-type hemoglobin allele (HbA) that codes for normal hemoglobin. Figure 3. Codon table showing nucleotide sequences for each amino acid. Figure 4. Image of a gel following electrophoretic separation of DNA fragments of the HBB gene from three individuals in the pedigree in Figure 1. The restriction endonuclease Mst II recognizes the sequence 5' CCT(N)AG (where N = any nucleotide) and cuts DNA at that site, producing separate fragments. Which of the following best explains the banding patterns exhibited in Figure 4. (A) The HbA DNA contains a recognition site for the Mst II restriction enzyme (B) The HBA/HbS DNA contains three recognition sites for the Mst II restriction endonuclease (C) Individual I has only one copy of the hemoglobin gene; therefore there is only one band on the gel (D) The HbS/HbA DNA contains three different alleles for sickle-cell disease
(A) The HbA DNA contains a recognition site for the Mst II restriction enzyme
Data regarding the presence (+) or absence (-) of five derived traits in several different species are show in the table below. Which of the following cladograms provides the simplest and most accurate representation of the date in the table?
(A) Y, W, V, Z, X
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 forelimbs 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 forelimbs that leads to the death of those cells
In a classic experiment from the 1970s investigating gene expression, a solution containing equal amounts of rabbit a-hemoglobin mRNA and B-hemoglobin mRNA, which encode subunits of a protein found in red blood cells, was injected into newly fertilized frog eggs. The injected mRNA was not degraded during the course of the experiment. Tadpoles that developed from the injected eggs were dissected into two fragments, one containing predominantly the notochord, muscle tissue, and nerve tissue and the other containing predominantly the other tissue types. Equal amount of the total proteins were analyzed after separation by elecrophresis to identify the relative amounts of the different proteins in each sample. The thickness of the bands indicates the relative amounts of rabbit a-hemoglobin, rabbit B-hemoglobin, and frog tubulin (cytoskeletal protein that is expressed at relatively constant levels in all tissues) present in each tadpole sample. The experimental protocol and results are summarized in the figure below. The electrophoresis results best support which of the following conclusions? (A) Cell specialization during development results in some cells losing the ablility to synthesize proteins. (B) Cells from different tissues share a common ability to use genetic material from a foreign source to produce protein (C) In comparison with other cells, nerve cells have a superior ability to produce cytoskeletal proteins (D) Muscle cells produce more B-hemoglobin than do cells from the other tissues in a tadpole
(B) Cells from different tissues share a common ability to use genetic material from a foreign source to produce protein
The following figures display data collected while studying a family, some members of which have sickle-cell disease--a rare genetic disorder caused by a mutation in the hemoglobin beta gene (HBB). There are at least two alleles of the HBB gene: the HbA allele encodes wild-type hemoglobin and the HbS allele encodes the sickle-cell form of hemoglobin. Genetic testing provided insight into the inheritance pattern for sickle-cell disease. Figure 1. Pedigree of a family with affected individuals. Square represent males, circles represent females, shaded symbols represent individuals with sickle-cell disease. Figure 2. A portion of the DNA sequence from the wild-type hemoglobin allele (HbA) that codes for normal hemoglobin. Figure 3. Codon table showing nucleotide sequences for each amino acid. Figure 4. Image of a gel following electrophoretic separation of DNA fragments of the HBB gene from three individuals in the pedigree in Figure 1. Based on the data shown in Figure 1, which of the following best describes the genotypes of individual family members in the pedigree? (A) All affected individuals possess at least one dominant allele of the hemoglobin beta gene (B) Healthy individuals may possess one mutant allele (HbS) of the hemoglobin beta gene (C) Individuals IV and V must be heterozygous for the HbS (mutant) allele (D) Individuals II and VI possess two copies of the HbA (wild-type) allele
(B) Healthy individuals may possess one mutant allele (HbS) of the hemoglobin beta gene
cystic fibrosis is a recessively inherited disorder that results from a mutation in the gene encoding CFTP chloride ion channels located on the surface of many epithelial cells. As shown in the figure, the mutation prevents the normal movement of chloride ions from the cytosol of the cell to the extracellular fluid. As a consequence of the mutation, the mucus layer that is normally present on the surface of the cells becomes exceptionally dehydrated and viscous. An answer to which of the following questions would provide the most information about the association between the CFTR mutation and the viscous mucus? (A) Is the mucus also secreted from the cells through the CFTR proteins? (B) How does the disrupted chloride movement affect the movement of sodium ions and water by the cell? (C) How does the mutation alter the structure of the CFTR proteins? (D) What is the change in nucleotide sequence that results in the CFTR mutation?
(B) How does the disrupted chloride movement affect the movement of sodium ions and water by the cell?
The following figures display data collected while studying a family, some members of which have sickle-cell disease--a rare genetic disorder caused by a mutation in the hemoglobin beta gene (HBB). There are at least two alleles of the HBB gene: the HbA allele encodes wild-type hemoglobin and the HbS allele encodes the sickle-cell form of hemoglobin. Genetic testing provided insight into the inheritance pattern for sickle-cell disease. Figure 1. Pedigree of a family with affected individuals. Square represent males, circles represent females, shaded symbols represent individuals with sickle-cell disease. Figure 2. A portion of the DNA sequence from the wild-type hemoglobin allele (HbA) that codes for normal hemoglobin. Figure 3. Codon table showing nucleotide sequences for each amino acid. Figure 4. Image of a gel following electrophoretic separation of DNA fragments of the HBB gene from three individuals in the pedigree in Figure 1. Possessing a single copy of the HbS allele has been shown to provide some resistance to infection by Plasmodium falciparum, the parasite that cuases malaria. Which of the following individuals represented in the pedigree would have the greatest selective advantage in an area where malaria is common? (A) I (B) II (C) III (D) V
(B) II
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 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 protection from predators
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.
The date below demonstrate the frequency of tasters and nontasters of a certain compound in four isolated populations that are in hardy-Weinberg equilibrium. The allele for nontasters is recessive. In which population is the frequency of the recessive allele highest? Pop. Taster Non. Size of pop. (A) 1 100 32 142 (B) 2 8,235 4,328 12,563 (C) 3 215 500 715 (D) 4 11,489 2,596 14,085
(C) 3 215 500 715
The figure above depicts the DNA-protein complex that is assembled at the transcriptional start site of gene X when the expression of gene X is activated in liver cells. Previous studies have shown that gene X is never expressed in nerve cells. Bases on the diagram, which of the following most likely contributes to the specific expression pattern of gene X? (A) Expression of gene X produces large amounts of tRNA but undetectable amounts of mRNA (B) The general transcription factors inhibit the activation of gene X in liver cells by blocking the activator from binding to RNA polymerase II (C) The activator is a sequence-specific DNA-binding protein that is present in some tissues but not in other tissues (D) The enhancer is a unique DNA segment that is added to the nuclear DNA of some cells of an organism during the process of mitotic cell division but not other cells
(C) The activator is a sequence-specific DNA-binding protein that is present in some tissues but not in other tissues
In a classic experiment from the 1970s investigating gene expression, a solution containing equal amounts of rabbit a-hemoglobin mRNA and B-hemoglobin mRNA, which encode subunits of a protein found in red blood cells, was injected into newly fertilized frog eggs. The injected mRNA was not degraded during the course of the experiment. Tadpoles that developed from the injected eggs were dissected into two fragments, one containing predominantly the notochord, muscle tissue, and nerve tissue and the other containing predominantly the other tissue types. Equal amount of the total proteins were analyzed after separation by elecrophresis to identify the relative amounts of the different proteins in each sample. The thickness of the bands indicates the relative amounts of rabbit a-hemoglobin, rabbit B-hemoglobin, and frog tubulin (cytoskeletal protein that is expressed at relatively constant levels in all tissues) present in each tadpole sample. The experimental protocol and results are summarized in the figure below. Which of the following conclusions is most consistent with the results for the experiment? (A) Rabbit mRNA is composed of nucleotides that are absent from frog mRNA (B) A larger volume of blood circulates through a rabbit than through a frog (C) The subunits of hemoglobin differ in size, shape, or charge (D) Synthesis of B-hemoglobin occurs at a faster rate in muscle cells than in other body cells
(C) The subunits of hemoglobin differ in size, shape, or charge
The following figures display data collected while studying a family, some members of which have sickle-cell disease--a rare genetic disorder caused by a mutation in the hemoglobin beta gene (HBB). There are at least two alleles of the HBB gene: the HbA allele encodes wild-type hemoglobin and the HbS allele encodes the sickle-cell form of hemoglobin. Genetic testing provided insight into the inheritance pattern for sickle-cell disease. Figure 1. Pedigree of a family with affected individuals. Square represent males, circles represent females, shaded symbols represent individuals with sickle-cell disease. Figure 2. A portion of the DNA sequence from the wild-type hemoglobin allele (HbA) that codes for normal hemoglobin. Figure 3. Codon table showing nucleotide sequences for each amino acid. Figure 4. Image of a gel following electrophoretic separation of DNA fragments of the HBB gene from three individuals in the pedigree in Figure 1. The HbS allele, which causes sickle-cell disease, results from a mutation in the DNA sequences shown in Figure 2 that produces a valine (val) in the place of a glutamic acid (glu) residue in the hemoglobin protein. Which of the following mRNA sequences is derived from the HbS allele? (A) 5' GAC TGA GGA CTC CTC TTC AGA 3' (B) 5' UCU GAA GAG GAA UCC UCA GUC 3' (C) 5' AGA CTT CTC CTC AGG AGT CAG 3' (D) 5' CUG ACU CCU GUG GAG AAG UCU 3'
(D) 5' CUG ACU CCU GUG GAG AAG UCU 3
A student in a biology class crossed a male Drosophila melanogaster having a gray body and long wings with a female D. melanogaster having a black body and apterous wings. The following distribution of traits was observed in the offspring. Phenotype Gray body, long wing 42 Black body, apterous wings 41 Gray body, apterous wings 9 Black body, long wings 8 Which of the following is supported by the data? (A) The alleles for gray body and long wings are dominant B) The alleles for gray body and long wings are recessive (C) Genes for the two traits are located on two different chromosomes (D) Genes for the two traits area located close together on the same chromosome, and crossing over occurred between the two gene loci
(D) Genes for the two traits area located close together on the same chromosome, and crossing over occurred between the two gene loci
In a classic experiment from the 1970s investigating gene expression, a solution containing equal amounts of rabbit a-hemoglobin mRNA and B-hemoglobin mRNA, which encode subunits of a protein found in red blood cells, was injected into newly fertilized frog eggs. The injected mRNA was not degraded during the course of the experiment. Tadpoles that developed from the injected eggs were dissected into two fragments, one containing predominantly the notochord, muscle tissue, and nerve tissue and the other containing predominantly the other tissue types. Equal amount of the total proteins were analyzed after separation by elecrophresis to identify the relative amounts of the different proteins in each sample. The thickness of the bands indicates the relative amounts of rabbit a-hemoglobin, rabbit B-hemoglobin, and frog tubulin (cytoskeletal protein that is expressed at relatively constant levels in all tissues) present in each tadpole sample. The experimental protocol and results are summarized in the figure below. The observation that the rabbit mRNA was successfully translated in the grog tissues supports which of the following conclusions? (A) Frog cells are able to replace their own hemoglobin with rabbit hemoglobin (B) Undeveloped frog eggs can be induced to form genetically identical copies of a rabbit (C) Rabbits hemoglobin can induce an immune response in frogs (D) Rabbits and frogs share a common genetic code for expressing heritable information
(D) Rabbits and frogs share a common genetic code for expressing heritable information
Ellis-van Creveld syndrome is a recessive genetic disorder that includes the characteristics of short stature and extra fingers or toes. In the general population, this syndrome occurs in approximately 1 in 150,000 live births. In a particular isolated population, however, the incidence of this syndrome among live births is 1 in 500. Assume that both the isolated population and the general population are in Hardy-Weinberg equilibrium with respect to this syndrome. Which of the following best describes the difference between the frequency of the allele that causes the syndrome in the general population and the frequency of the allele in the isolated population? (A) The frequency of the Ellis-van Creveld allele is 0.002 in the isolated population and 0.000066 in the general population, which suggests that selection for this trait is occurring in both population (B) The frequency of the Ellis-van Creveld allele is 0.0447 in the isolated population and 0.0026 in the general population, showing that the rate of genetic mutation is highest among individuals in the isolated population. (C) The frequency of the Ellis-van Creveld allele is 0.002 in the isolated population and 0.0000066 in the general population, which demonstrates gametic incompatibility between the populations. (D) The frequency of the Ellis-van Creveld allele is 0.0447 in the isolated population ad 0.0026 in the general population, which suggest that genetic drift has occurred in the isolated population.
(D) The frequency of the Ellis-van Creveld allele is 0.0447 in the isolated population ad 0.0026 in the general population, which suggest that genetic drift has occurred in the isolated population.
In a classic experiment from the 1970s investigating gene expression, a solution containing equal amounts of rabbit a-hemoglobin mRNA and B-hemoglobin mRNA, which encode subunits of a protein found in red blood cells, was injected into newly fertilized frog eggs. The injected mRNA was not degraded during the course of the experiment. Tadpoles that developed from the injected eggs were dissected into two fragments, one containing predominantly the notochord, muscle tissue, and nerve tissue and the other containing predominantly the other tissue types. Equal amount of the total proteins were analyzed after separation by elecrophresis to identify the relative amounts of the different proteins in each sample. The thickness of the bands indicates the relative amounts of rabbit a-hemoglobin, rabbit B-hemoglobin, and frog tubulin (cytoskeletal protein that is expressed at relatively constant levels in all tissues) present in each tadpole sample. The experimental protocol and results are summarized in the figure below. Which of the following is the best justification for why the rabbit hemoglobin proteins were found throughout the tadpole? (A) Rabbit mRNA is composed of nucleotide that are more stable than those in frog mRNA (B) Rabbit hemoglobin is synthesized more efficiently than frog hemoglobin in frog cells (C) After differentiation, the rabbit hemoglobin proteins move through the circulatory system to the tadpole to every cell (D) The mRNA injected into the newly fertilized frog eggs is distributed in the cytoplasm of every daughter cell during cell division
(D) The mRNA injected into the newly fertilized frog eggs is distributed in the cytoplasm of every daughter cell during cell division