Ap Bio: Practice Qs
Picture of cladogram The validity of the eladogram is best supported by molecular evidence for which of the following changes in the amino acid composition of the beta-hemoglobin protein during the evolution of these species? (A) Arginine to leucine at position X on the cladogram (B) Arginine to leucine at position Y on the cladogram (C) Leucine to arginine at position W on the cladogram (D) Leucine to arginine at position Z on the cladogram
(A) Arginine to leucine at position X on the cladogram
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 dinerent temperatures. Within the same population, but most effective at 29 ° C, while others most effective at 40 C. Still others can be equal at both temperatures, which is most consistent with the observed butterfly behavior? (A) Butterflies that express two variants of the enzyme are active over a greater range of temperature. (B) Butterflies that are active over a wide range of temperatures produce greater amounts of the enzyme. (C) Temperature has little effect on the activity of butterflies. (D) Butterflies that are active at warmer temperatures produce more offspring.
(A) Butterflies that expre or variations of the enzyme are used over a greater range of temperature.
Sickle-cell anemia is associated with a mutation in the gene encoding the beta subunit of glutamic hemoglobin that results in a change from acid to valine at position 6. All other amino acids are identical to a normal hemoglobin molecule. Based on the information above, which of the following mutations is the most likely cause of sickle-cell anemia? (A) A single base-pair substitution in the gene encoding the beta subunit (B) A single base-pair insertion in the gene encoding the beta subunit (C) A single base-pair deletion in the gene encoding the beta subunit (D) A translocation of DNA from one chromosome to another
(A) A single base-pair substitution in the gene encoding the beta subunit
Which of the following best explains why GFP* might exhibit a bright green fluorescence in alkaline conditions but not in acidic conditions? (A) Addition of an H+ to GFP* at acidic pH changes the shape of the protein, preventing fluorescence. (B) CDK5 is a degrading enzyme that hydrolyzes GFP* at alkaline pH, preventing fluorescence. (C) An influx of protons into the axon terminal activates synthesis of new GFP* molecules, preventing fluorescence. (D) Packaging of GFP* into synaptic vesicles is triggered by a sudden drop in cytosolic pH, preventing fluorescence.
(A) Addition of an H+ to GFP* at acidic pH changes the shape of the protein, preventing fluorescence.
To investigate whether an organism in the study is capable of both photosynthesis and respiration, a comparison of which treatment groups is most appropriate? (A) I and II (B) II and IV (C) III and V (D) IV and VI
(A) I and II
Which of the following best describes the reproductive ability of C elegans following the ARD induced in the first experiment? (A) Mating with a well-fed male consistently produced more offspring than did reproduction via self-fertilization. (B) The numbers of progeny produced by self-fertilization and by mating with well-fed males were not statistically different. (C) C. elegans stopped reproducing after 20 days without food. (D) There was no relationship between days without food and average brood size.
(A) Mating with a well-fed male consistently produced more offspring than did reproduction via self-fertilization.
Using the model of speciation and applying it to a different population, which of the following outcomes is most consistent for a different species in which the ailments are homogametic and the females are heterogametic? (A) Sterility would appear in females before appearing in males. (B) Speciation would occur more rapidly because females would produce more offspring. (C) Behavioral isolation would occur sooner in species exhibiting nonrandom mating. (D) The population would reach Hardy-Weinberg equilibrium at an accelerated rate.
(A) Sterility would appear in females before appearing in males.
In the year 2000, specimens of Caulerpa taxifolia, green alga used in tropical aquariums, were found off the coast of California, Native to the Indian Ocean, C. tarifolia is known for aggressive growth and ability to compete with sea grasses' it is currently on an international list of invasive species. Which of the following best predicts the consequences of the introduction of C. tarifolia to the California coast? (A) Without natural herbivores or competitors, C. taxifolia will grow rapidly and crowd out native species of producers (B) C taxifolia will have a hard time establishing itself because it will have to compete against native species of sea grasses, which are better adapted to the environment (C) C taxifolia will grow rapidly, leading to an increase in the diversity of producers (D) Because it is not in the Indian Ocean, its natural environment, C. taxifolia will not be able to grow efficiently.
(A) Without natural herbivores or competitors. C. taxifolia will grow rapidly and crowd out native species of producers.
The average brood size per individual mated upon reintroduction of food following 30 days of ARD is closest to which of the following? (A) 10 (B) 50 (C) 250 (D) 400
(B) 50
Mitochondria are found in most eukaryotic cells and contain their own DNA and ribosomes that are similar to those of many prokaryetic cells. Which of the following statements is justified by these observations? (A) The mitochondrion is the only location in which eukaryotic cells can synthesize atp (B) An ancestral cell most likely engulfed and aerobic prokaryote in a relationship that proved beneficial for both cells (C) Mitochondrial membrane provide abundant surface area for reactions because of the infoldings called cristae (D) The mitochondrion plays a role in respiration but it also stores the cell's mRNA
(B) An ancestral cell most likely engulfed an aerobic prokaryote in a relationship that proved beneficial for both cells.
Lab question of light/dark/plants/fish in water Which of the following graphs is the most appropriate representation of the experimental results documented in the table? (A) Pie chart (B) Bar graph (C) Line graph (D) Standard error graph
(B) Bar graph
# of Cacti vs. # of Spines graph In a species of cactus, the number of spines on a plant is genetically determined. The graph above shows frequency distributions for populations of the cactus growing in the presence or absence of two herbivores: peccaries (a New World pig) and wasp larvae. Which of the following best accounts for the different frequency distributions in the graph? (A) Peccaries eat cacti with the greatest number of spines, and wasp larvae show no preference with respect to spine number. (B) Peccaries eat cacti with a smaller number of spines, and wasp larvae eat cacti with a greater number of spines. (C) Wasps have increasing difficulty depositing eggs on cacti with more spines, and peccaries show no preference with respect to spine number. (D) Both peccaries and wasp larvae will eat the most abundant types of cacti, which are the plants with the greatest number of spines.
(B) Peccaries eat cacti with a smaller number of spines, and wasp larvae eat cacti with a greater number of spines.
Picture of DNA damage The p53 protein regulates a cellular response to DNA damage. Based on the diagram above, which of the following best describes the role of p53 in the response to DNA damage? (A) Phosphorylated p53 binds to DNA and repairs the damage. (B) Phosphorylated p53 stimulates transcription of p21, and the resulting p21 protein suppresses cell division until the DNA damage is repaired. (C) Phosphorylated p53 binds cyclin-Cdk complexes, and the resulting protein complex repairs the DNA damage. (D) Phosphorylated p53 activates p21 proteins, and the p21 proteins in turn repair the DNA damage.
(B) Phosphorylated p53 stimulates transcription of p21, and the resulting p21 protein suppresses cell division until the DNA damage is repaired.
Based on the model, which of the following describes the most likely mechanism by which CDK5 regulates neurotransmitter release? (A) CDK5 adds methyl groups to DNA, altering expression of genes required for synthesis of neurotransmitters. (B) CDK5 promotes the rearrangement of the lipid molecules of two bilayers into a single membrane. (C) CDK5 alters the activity of other proteins involved in the movement of synaptic vesicles to the plasma membrane. (D) CDK5 binds to gated ion channels in the postsynaptic membrane, resulting in diffusion of calcium ions.
(C) CDK5 alters the activity of other proteins involved in the movement of synaptic vesicles to the plasma membrane.
Second base in Codon chart 5'-GACCGCAUGGUGACGAAAUU UGGCCAUUAA- 3' Based on the universal genetic code, which of the following represents the correct polypeptide that will result from translation of the mRNA molecule shown, beginning with the available start codon? (A) Asp-Arg-Met-Val-Thr-Lys-Phe-Gly-His (B) Met-Arg-Asp-Stop-His-Gly-Phe-Lys-Thr-Val (C) Met-Val-Thr-Lys-Phe-Gly-His (D) Val-Thr-Lys-Phe-Gly-His
(C) Met-Val-Thr-Lys-Phe-Gly-His
Which of the following best describes the reason for excluding hybrid diseases when calculating the allele frequencies of two interbreeding populations at the intermediate stage of speciation (Figure 2)? (A) The process of mate selection in large groups often favors females over males. (B) The frequency of sex-determining chromosomes is usually equal to 0.5. (C) Sterile individuals make no genetic contribution to the next generation. (D) The chance of inheriting a recessive allele from a male is too small to calculate.
(C) Sterile individuals make no contribution to the next generation.
Which of the following observations provides the best evidence that photosynthesis occurred in treatment group 1? (A) The specimens in the beakers were aquatic plants from a large aquarium. (B) The beakers were placed in the light. (C) The mean pH of the samples increased after one hour. (D) The standard error of the mean was smaller
(C) The mean PH of the samples increased after one hour.
The pedigree below shows the inheritance of a dominant allele of a gene in a family over several generations. Circles represent females and squares represent males. Shaded symbols indicate individuals carrying the allele. (A) mitochondrial genes are not heritable (B) mitochondrial mutations cannot produce dominant traits (C) maternal mitochondrial mutations are inherited by all of a mother's offspring (D) mitochondrial DNA is circular, whereas chromosomal DNA is linear
(C) maternal mitochondrial mutations are inherited by all of a mother's offspring
The results for treatment groups V and VI could you suggest which of the following questions about the design of the experiment? (A) Do the glass beakers prevent light from reaching the test samples? (B) Is the method used for measuring pH harmful to aquatic organisms? (C) Is the availability of carbon dioxide a limiting factor in aquatic ecosystems? (D) Does the aquarium water contain living microorganisms?
(D) Does the aquarium water contain living microorganisms?
A cell is treated with a drug that prevents the formation of new lysosomes. The cell continues to transcribe the genes that code for the hydrolytic enzymes that are normally found in lysosomes and continues to translate the mRNAs for those proteins on membrane-bound ribosomes. The hydrolytic enzymes are most likely to accumulate in which of the following cellular structures? (A) Nucleus (B) Mitochondrion (C) Smooth endoplasmic reticulum (D) Golgi complex
(D) Golgi complex
Which of the following observations best supports the hypothesis that CDK5 negatively regulates neurotransmitter release? (A) Introduction of CDK5 protein into neurons results in the movement of synaptic vesicles to the plasma membrane in the absence of any stimulus. (B) Uptake of a gene encoding CDK5 by neurons results in the movement of synaptic vesicles to the plasma membrane in the absence of any stimulus. (C) Suppression of CDK5 expression in neurons inhibits the movement of synaptic vesicles to the plasma membrane in response to a specific stimulus. (D) Inhibition of CDK5 activity in neurons increases the movement of synaptic vesicles to the plasma membrane in response to a specific stimulus.
(D) Inhibition of CDK5 activity in neurons increases the movement of synaptic vesicles to the plasma membrane in response to a specific stimulus.
As depicted in the diagram, honeybees communicate the location of flower patches to members of their model? dances that give information about the direction and distance to the flowers. Which the following statements about how honeybees communicate the position of flower patches is most consistent with the model? (A) The number of repetitions of the waggle dance indicates the quality of the pollen source. (B) The total area covered by any waggle dance leads bees to the target flowers. (C) The angle of the waggle phase relative to the vertical plane indicates the position of the target flowers relative to another beehive. (D) The farther the target flowers from the hive, the longer the waggle phase.
(D) The farther the target flowers from the hive, the longer the waggle phase.
Which of the following statements is best supported by the data? (A) Black bears are a keystone species (B) Salmon are a keystone species. (C) Black bear urine is a significant source of nitrogen in the environment. (D) The presence of black bears and salmon correlates with a significant increase in nitrogen influx.
(D) The presence of black bears and salmon correlates with a significant increase in nitrogen influx.
The graph above represents the number of individuals in a population of wolves and in a population of moose observed in the same isolated geographic area over a 40-year period, from 1955 through 1995. Which of the following statements about the two populations is best supported by the information presented in the graph? (A) The reproductive rate of the wolves was greater than the reproductive rate of the moose. (B) Mutualism allowed the two populations to reproduce while occupying the same ecological niche. (C) Speciation occurred when the two populations became reproductively isolated from each other. (D) The wolves were predators of the moose, which were otherwise reproductively successful.
(D) The wolves were predators of the moose, which were otherwise reproductively successful.
Zucchini squash in sucrose graph... Using teh straight line on the graph above, calculate the water potential (in bars) of the zucchini squash at 21C. Give your answer to one decimal place.
-8.8 bars
Epinephrine is a protein hormone found in many animals. Epinephrine is a signaling pathway that results in the breakdown of glycogen to glucose in the liver cells. Which of the following describes the initial steps in the process whereby epinephrine stimulates glycogen breakdown? (A) Epinephrine binds to a cell-surface receptor; the activated receptor stimulates production of the second messenger, cAMP. (B) Epinephrine binds to a cell-surface receptor; the activated receptor catalyzes the conversion of glycogen to glucose. (C) Epinephrine diffuses through the plasma membrane; the hormone dimerizes in the cytosol. (D) Epinephrine is taken into the cell by endocytosis; glycogen is converted to glucose in the endocytotic vesicle.
(A) Epinephrine binds to a cell-surface recep receptor; the activated receptor stimulates production of the second messenger, cAMP
The table shows the changes in allele frequencies of a specific gene in two populations of randomly mating small mammals after 30 years. The populations inhabit adjacent equatorial islands that have similar topography and climate. Which of the following is the most reliable conclusion that can be drawn from the analysis of the data above? (A) Genetic drift has occurred in population 1. (B) Population 2 is in Hardy-Weinberg equilibrium. (C) Selection for allele r is occurring in both populations. (D) The reduced frequency of allele R in population 1 will eventually lead to the extinction of population 1.
(A) Genetic drift has occurred in population 1
Based on the model of speciation presented, which of the following describes the most likely consequence to the populations over time? (A) Hybrid individuals are less likely to pass their genetic information on to subsequent generations. (B) Hybrid individuals living together are physically unable to mate with each other. (C) Geographically isolated populations gradually acquire similar heritable traits. (D) Differences between hybrid individuals of a species disappear over time.
(A) Hybrid individuals are less likely to pass their genetic information on to the subsequent generations.
Transmission of an action potential across synapse involves the release of neurotransmitters by the presynaptic neuron. The arrival of the action potential triggers to rise in the calcium concentration in the terminal synaptic, and the change in concentration triggers to release of neurotransmitters into the synaptic cleft. Which of the following representations of the movement of calcium, sodium, and potassium ions best shows how an action is transmitted to the postsynaptic neuron? (A) NA+ arrow entering on right top. K+ arrow leaving on bottom right. Ca++ entering. (B) NA+ arrow entering on right top. K+ arrow leaving on bottom right. Ca++ leaving. (C) NA+ arrow leaving on right top. K+ arrow leaving on bottom right. Ca++ leaving. (D) NA+ arrow leaving on right top. K+ arrow entering on bottom right. Ca++ entering.
(A) NA+ arrow entering on right top. K+ arrow leaving on bottom right. Ca++ entering.
Based on the experimental results, which of the following is the best evolutionary explanation for occurrence of ARD in C. elegans? (A) The ability to enter ARD provides a strong selective advantage because reproduction can occur despite periods of food scarcity. (B) Acquiring the genes for ARD gives individuals a selective advantage because they produce more offspring than do individuals who cannot enter ARD. (C) Individuals who can enter ARD are selected for in the population because they live longer than do individuals who cannot enter ARD. (D) Individuals who can enter ARD have high fitness because they can reproduce even when food is scarce.
(A) The ability to enter ARD provides a strong selective advantage because reproduction can occur despite periods of food scarcity.
A scientist is evaluating a proposal for raising large numbers of fish in ocean pens for human. As part of the evaluation, the scientist is designing a plan for investigating how the fish in the ocean pens might affect nearby ecosystems. Which of the following is the most appropriate factor to use as the variable variable in the experimental investigation? (A) The amount of metabolic wastes in the water where the fish are being raised (B) The water temperature in the natural habitat of the fish being studied (C) The types of fish that are preferentially consumed by humans (D) The amount of time it takes for fish to digest a meal
(A) The amount of metabolic wastes in the water where the fish are being raised
Which of the following pieces of additional data would help further investigate the relationship between bears, salmon, and the influence of nitrogen into the local environment? (A) The experimenters should remove the remains of salmon carcasses immediately after the salmon are eaten by the bears and determine the nitrogen content of the carcasses. (B) The experimenters should increase the number of bears in the area and measure the amount of nitrogen available for uptake by plants. (C) The experimenters should set up a net to catch salmon before they enter the area and then measure nitrogen influx. (D) The experimenters should clear-cut the trees from the area and determine how much nitrogen remains in the streams.
(A) The experimenters should remove the remains of salmon carcasses immediately after the salmon are eaten by the bears and determine the nitrogen content of the carcasses.
Which of the following most likely describes how the interaction between bears and salmon influences nitrogen dynamic in the environment? (A) When bears consume salmon, they leave parts of the carcasses on the ground, which decompose, releasing nitrogen into the environment. (B) When salmon swim upstream to spawn, bears migrate to the rivers and deposit nitrogen from the forest with their excrement. (C) Bears are a reservoir for nitrogen because they are the top consumer in the environment. (D) Bears urinate in rivers and streams, which provides nitrogen for the salmon.
(A) When bears consume salmon, they leave parts of the carcasses on the ground, which decompose, releasing nitrogen into the environment.
Previous experiments indicate that CDK5 is active only when attached to a protein called p35. Which of the following best predicts how p35 might play a role in regulating neuron function? (A) Elevated intracellular levels of p35 result in increased synaptic activity. (B) Degradation of p35 results in increased synaptic activity. (C) Reabsorption of p35 from the synaptic cleft results in increased synaptic activity. (D) Attachment of p35 to synaptic vesicles results in increased synaptic activity.
(B) Degration of p35 results in increased synaptic activity.
Which of the following scientific questions is most relevant to model represented in the figure above? (A) Is ATP required for the transportation of sugars across the outer mitochondrial membrane? (B) Do the types of phospholipids in a membrane affect the rate at which molecules enter a cell by passive diffusion? (C) Which molecular substance is actively transported across the plasma membrane? (D) How does temperature affect the movement of molecules into lysosomes?
(C) Which molecular substance is actively transported across the plasma membrane?
Based on the model, which of the following best explains how regulation of neurotransmitter release might increase the range of responses to a stimulus in the nervous system? (A) In the absence of any stimulus, neurons can still release neurotransmitters. (B) Different neurons in the same neural network can release different amounts of neurotransmitter. (C) In the depolarization phase of an action potential, postsynaptic neurons can adjust the amount of neurotransmitter bound to receptors on their surface. (D) In the recovery phase following a stimulus, enzymes can be mobilized to degrade molecules present in the synaptic vesicles.
(B) Different neurons in the same neural network can release different amounts of neurotransmitter.
In a separate investigation, individual from different populations that are geographically isolated from each other are mated in the laboratory. The hybrid offspring were then mated with individuals from either of the original populations. Only the female hybrid offspring were fertile. The experimental results are most consistent with which of the stages that are depicted in the model? (A) Initial population (Figure 1) (B) Intermediate stage (Figure 2) (C) Late stage (Figure 3) (D) Terminal stage (Figure 4)
(B) Intermediate stage (Figure 2)
If a dam is built downstream and prevents salmon migration to the test sites, which of the following most accurately predicts the impact on nitrogen flux? (A) Nitrogen influx will increase because the bears will no longer store nitrogen from the salmon. (B) Nitrogen influx will decrease because there will be less bear-salmon interaction. (C) Nitrogen influx will remain stable because organisms other than bears and salmon will mobilize nitrogen in the environment. (D) Nitrogen influx will increase because bears will no longer lose nitrogen to the salmon.
(B) Nitrogen influx will decrease because there will be less bear-salmon interaction.
In Drosophila melanogaster for wild-type tan body color (B) is dominant to the recessive allele for black body color (b). Similarly, the allele for wild type wing shape (V) is dominant to the recessive allele for vestigial wing phenotype (v). In the cross diagrammed above, the expected and observed results are shown. Which of the following best explains the observed results of the cross? (A) The alleles for body color and wing shape assort independently, as predicted by Mendel's laws. (B) The genes for body color and wing shape are located close to each other on the same chromosome. (C) The traits of body color show complete dominance over the traits of wing shape. (D) The observed variations in body color and wing shape are detectable in males but not in females.
(B) The genes for body color and wing shape are located close to each other on the same chromosome.
The table below provides a comparison of nitrogenous waste production in selected organisms. Which of the following statements is most consistent with the data in the table? (A) In response to the hypotonic environment in which freshwater fish live, they excrete ammonia in concentrated urine or across their gills. (B) The kidneys of reptiles and birds are highly efficient because little water is needed to excrete uric acid. (C) Birds excrete ammonia in addition to uric acid, and the ratio of the two substances is independent of whether the birds are primarily terrestrial or aquatic species. (D) The similar regulation of extracellular fluid volume and composition in all the organisms suggests conservation of kidney structure throughout evolution.
(B) The kidneys of reptiles and birds are highly efficient because little water is needed to excrete Uriel acid.
Which of the following statements best justifies the claim that the conditions in at least one of the experiments could generate the molecular building blocks essential for life? (A) The carbon dioxide (CO2) gas and water (H2O) vapor in experiment 1 could react spontaneously to produce the phospholipids required by the first life-forms. (B) The nitrogen (N2) gas and ammonia (NH3) gas in experiment 1 could provide the elemental nitrogen required for the formation of amino acids. (C) The sulfur dioxide (SO2) gas in experiment 2 could donate the excited electrons required to drive the process of photosynthesis. (D) The methane (CH4) gas in experiment 2 could act as the electron acceptor required to complete the process of cellular respiration.
(B) The nitrogen and ammonia gases in experiment 1 could provide the elemental nitrogen required for the formation of the AAs.
Some strains of the bacterium Streptococcus pyogenes secrete poisonous substances called genes encoding the exotoxins are thought to have originated in bacteriophages, which are viruses that infect bacteria. Which of the following is the most likely the by which S. pyogenes has the ability to produce the exotoxins? (A) Bacteriophages engulfed cellular debris from dead bacteria. (B) Bacteriophages in the environment activated bacterial cell division. (C) Bacteriophage DNA became integrated in the bacterial chromosome. (D) Bacteriophage proteins were absorbed into bacteria cells by endocytosis.
(C) Bacteriophage DNA became integrated in the bacterial chromosome.
Researchers investigating the regulation of neurotransmitter release from presynaptic neurons proposed a model (Figure 1) in which CDK5, a protein expressed in axon terminals, inhibits the movement of synaptic vesicles to the presynaptic membrane. Based on the model, which of the following best explains why a bright green fluorescence was observed following stimulation of a presynaptic neuron? (A) GFP* synthesis was activated when a gene taken up by the neuron was switched on. (B) GFP* stored in the cytoplasm of the neuron was packaged into synaptic vesicles. (C) GFP* contained in synaptic vesicles moved into the synaptic cleft by exocytosis. (D) GFP* present in the synaptic cleft was reabsorbed by endocytosis into the neuron.
(C) GFP* contained in synaptic vesicles moved into the synaptic cleft by exocytosis.
Scientists are studying several populations of finches on neighboring islands in the South Pacific. Previous genetic analysis has shown that a single gene controls tail-feather length in the finch populations and that the allele for long tail feathers (L) is dominant to the allele for short tail feathers (l). On two separate islands, the scientists recorded the number of finches with long tail feathers and the number of finches with short tail feathers. The results are shown in the table below. If the two finch populations are each in Hardy-Weinberg equilibrium and are isolated from each other, then which of the following graphs correctly displays the relative genotype frequencies? (A) Graph containing LL = .45 (island 1) LL= .31 (island 2) (B)Graph containing LL = .16 (island 1) LL= .24 (island 2) (C) Graph containing LL = .21 (island 1) LL= .2 (island 2) (D) Graph containing LL = .51 (island 1) LL= .49 (island 2)
(C) Graph containing LL = .21 (island 1) LL= .2 (island 2)
Many human cells can be stimulated to divide by hormone like growth factors that bind to receptor proteins (R) on the plasma membrane and trigger an internal signal-transduction cascade. In many cases, however, the process of contact inhibition prevents mitosis when cells are in direct contact with one another. Contact inhibition occurs when proteins called cell adhesion molecules (CAMs) interact, causing them to change shape so that the growth-factor signaling proteins that normally associate with CAMs are replaced by another protein, called M. Both pathways are depicted in the figures below. Which of the following statements accurately uses the information presented to support the hypothesis that interruption of M function in a single body cell can result in cancer?
(C) Growth factor signaling can trigger mitosis in cells that are in direct contact with other cells.
Some cells release active signaling proteins when membrane-bound precursor proteins are cleaved by proteolytic enzymes. The signaling proteins can then bind to receptors on the surface of a target cell, thereby activating an intracellular signaling pathway and eliciting a response from the target cell. This mechanism of activating receptor-binding signaling proteins has been observed in a variety of organisms from bacteria to humans. Many of the enzymes responsible for proteolysis of membrane-bound precursor proteins have been isolated and characterized. Which of the following questions would be most appropriate to investigate whether the proteolytic enzymes are evolutionarily conserved among species? (A) Are the genes encoding the proteolytic enzymes expressed in the same cell types in all species? (B) Once the precursor proteins of different species are cleaved, do the active signaling proteins bind to the same receptors on different target cells? (C) If a proteolytic enzyme from one species is incubated with a precursor protein from another species, does correct cleavage occur? (D) Are the proteolytic enzymes synthesized in the rough endoplasmic reticulum of all species?
(C) If a proteolytic enzyme from one species is incubated with a precursor protein from another species, does correct cleavage occur?
High blood cholesterol (hypercholesterolemia, HC) can lead to cardiovascular problems such as atherosclerosis and heart attack. Exercise and monitoring of diet can often control cholesterol levels; however, in certain cases HC is inherited as an autosomal dominant disease caused by a mutation in a single gene. A man with high cholesterol levels is about to marry a woman whose total cholesterol levels are also higher than average. A doctor has suggested they got tested for the HC allele. Which of the following is a valid ethical question about the test? (A) How important are the results of the test to the couple's health, since they already know they have HC? (B) How can they eliminate the allele for HC from their cells? (C) If both have the allele for HC, should an insurance company raise their rates because of the results of the test? (D) What cures are available for HC other than dietary changes and exercise?
(C) If both have the allele for HC, should an insurance company raise their rate because of the results of the test?
Which of the following modifications to the experimental design will the best help reduce the standard errors of the means? (A) Using pond water instead of aquarium water (B) Exposing samples to light for a greater amount of time (C) Increasing the sample size of each treatment group (D) Collecting organisms from a natural water source instead of an aquarium
(C) Increasing the sample size of each treatment group
A group of students designed an experiment to deferinto the compost on the germination and growth of plants. The students ber up plots by mising different ratios of oil and compost. They planted 20 pea and 20 melon seeds in each plot and watered each plot regularly. The students recorded the number of seeds that germinated, and the plants grew, plant length, and size of leaves, and general health observations The following observations were recorded. In all treatments, meme pea seeds germinated than melom seeds. There was a veek of rainy weather at three weeks. Melon plants developed to fungal growth at four weeks, Melon plants grew longer than pea planis, but many melon leaves showed signs of yellowing as the woekx passed. The students said that pea plants grew better in compost than did melon plants. Which of the following best addresses the validity of the conclusion made by the students? (A) The conclusion is valid because the independent and dependent variables in the experiment were controlled. (B) The conclusion is valid because the experimental design included a large sample size. (C) The conclusion is invalid because other variables in the experiment (both biotic and abiotic) affected the results. (D) The conclusion is invalid because the units of measurement were not given in the experimental design.
(C) The conclusion is invalid because other variables in the experiment (biotic and abiotic) affected the results.
Which of the following conclusions is most consistent with the data shown in Figure 2? (A) Animals that spend 3-5 days in ARD are more likely to survive periods of food scarcity than are animals that spend 13-15 days in ARD. (B) Animals that spend 30 days in ARD live significantly longer after reintroduction of food than animals that spend only 3 days in ARD. (C) The number of days an animal spends in ARD does not significantly affect its time of survival after reintroduction of food. (D) The large standard errors of the means make conclusions from the data impossible.
(C) The number of days an animal spends in ARD does not significantly affect its time of survival after reintroduction of food.
Two populations of a species of squirrel are geographically isolated from each other. Although they have the same population density one population is significantly larger in number than the other. A new bacterial disease, which is easily spread and extremely virulent, affects both populations at the same time. Which of the following is the best prediction how will the new disease affect the two populations? (A) The two populations will be equally affected, because the ability to trigger an immune response is randomly distrubted among all squirrrels of that species (B) The larger population will be less affected by the disease than will the smaller population, because the mutation rate of the larger population is higher than the mutation rate of the smaller population (C) The smaller population will be more affected than the larger population, because the smaller population has less genetic variation than the larger population has. (D) The smaller population will be less affected than will the larger population, because the smaller population exhibits more genetic drift than the larger population exhibits
(C) The smaller population will have more affected than will the larger population, because the smaller population has less genetic variation than the larger population has.
Picture of signaling diagram for steroid hormones Based on the information presented, what of the following will also occur in response to steroid signaling? (A) Histone protein synthesis will increase because histones maintain the DNA in an optimal conformation for chromosome assembly. (B) Ribosome production will increase because ribosomes are specific for the mRNA with which they bind during translation. (C) DNA replication will increase as a result of the binding of the hormone-receptor complex to the DNA. (D) Production of a specific mRNA will increase as a result of the binding of the hormone-receptor complex to the DNA.
(D) Production of a specific mRNA will increase as a result of the binding of the hormone-receptor complex to the DNA.
Eye pigment in a particular strain of fly is determined by two genes. An autosomal gene that controls the color of the pigments in the eye two alleles: a dominant allele has (R) red eyes and a recessive to (r) that results in sepia eyes. A sex-linked gene that controls the expression of the colored pigments also has two alleles: a dominant allele (T that allows for expression of the colored pigments and a recessive allele (t) that does not allow for expression of the colored pigments. Which of the following represents a cross between a white-eyed male and a red-eyed female? (A) Tt XRXR × tt XrY (B) Tt XrXr × tt XRY (C) RRXTXT×RrXTY (D) RrXtXt×RrXTY
(D) RrXtXt×RrXTY
The data above represents 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? (A) The allele for white is an autosomal dominant allele because a 1:1 phenotype ratio of blue to white among both sexes is observed in cross 3. (B) The allele for blue is an autosomal dominant allele because an approximate 3:1 phenotype ratio of blue to white is observed in cross 1. (C) The allele for white is an X-linked dominant allele because no white females are produced in cross 1. (D) The allele for blue is an X-linked dominant allele because there are no blue male offspring in cross 2.
(D) The allele for blue is an X-linked dominant allele because there are no blue male offspring in cross 2
Fruit flies (grid-in) A true-breeding female with wild-type wings and white eyes is crossed with a male with vestigial wings and red eyes. What proportion of the offspring are expected to be evil with wild-type wings and white eyes? Give your answer as a fraction or a decimal value from 0 to 1.
.5
ABO blood type in humans... Assuming that the population is in Hardy- Weinberg equilibrium with respect to blood type what is the frequency of the i allele? Give your answer to two decimal places.
.67
Biological communities containing a large number of species that are evenly distributed exhibit high species diversity... Calculate the Simpson's index of diversity for the community of trees. Enter your answer as a value between 0 and 1 to the nearest hundredth.
0.64-0.66
Cladogram (grid-in) Based on the information presented, which of the derived characters is shared by alligators and mantees but not salamanders? Give you answer as the number label of a character indicated on the cladogram.
3
