AP Bio SEM B Final Exam
This table shows the codons found in messenger RNA. Using this information, what sequence of nucleotides in the template strand of DNA could code for the polypeptide sequence Val-His-Thr?
**I think 3' CAT- GTA- TGG 5' **
Which of the following involve(s) a decrease in the amount of negative charge in a cell? (1 point) 1. An action potential 2. Depolarization 3. Hyperpolarization
1 and 2
Which of the following molecules are produced during transcription? (2 points) 1. Messenger RNA 2. Ribozymes 3. Ribosomal proteins
1. and 2. only
In the cross AaBbCc x AaBbCc, what is the probability of producing offspring with the genotype AABBCC?
1/64
A man who is an achondroplastic dwarf with normal vision marries a color-blind woman of normal height. The man's father was of normal height, and both the woman's parents were also of average height. Achondroplastic dwarfism is autosomal dominant, and red-green color blindness is an X-linked recessive trait. They have a daughter who is a dwarf with normal color vision.What is the probability that she is heterozygous for both genes?
100%
In a lake ecosystem, the energy used by autotrophs for respiration is 2,100 kcal/m2 per year. If the gross primary production for this ecosystem is 4,400 kcal/m2 per year, what is the net primary production? (2 points)
2,300 kcal/m2 per year
A triplet of bases in a template strand of DNA is 5' CAG 3'. What would be the corresponding codon for mRNA?
3' GUC 5'
A triplet of bases in the template strand of DNA is 5' AGT 3'. What would be the corresponding codon for mRNA?
3' UCA 5'
Which number identifies the root-tip epidermis? (1 point)
3.
A sparrow eats 1200 J of seeds. Of this, 425 J is eliminated as feces and 750 J are used in cellular respiration. What is the approximate production efficiency of this animal? (2 points)
3.2%
A population of 41 salamanders undergoes linear growth for a period of five years with an average growth rate of 1.2 salamanders per year. What is the salamander population after this period of growth? (1 point)
47 salamanders
If a terrestrial ecosystem has a net primary production of 3000 J/m2 *yr and an Ra of 2000, what is the gross primary production for this ecosystem? (2 points)
5000
A population of 13 birds exhibits linear growth, with an average growth rate of 2.4 individuals per year. If environmental conditions and growth rate remain the same, how long would it take the population to increase to 156 birds?
59.60 years
In a marsh ecosystem, the carrying capacity for a population of turtles is 325, and the maximum rate of increase for this population is 1.0 per individual per year. Using the logistic population growth model, what is the approximate population growth rate for 213 turtles? (2 points)
73 turtles per year
In a population of deer, each deer consumes, on average, plants containing 650 J of energy. If 345 J of this is excreted in feces and 280 J is used for respiration, what is the production efficiency of the deer? (2 points)
8.2%
Which statement best explains how an asteroid or large comet could have caused the Cretaceous mass extinction? (1 point)
A layer of clay that marks this period in the stratified sediment is enriched with an exogenous mineral known to be present in meteorites.
Which of the following does not occur in prokaryotic gene expression but does in eukaryotic gene expression?
A poly-A tail is added to the 3' end of mRNA, and a cap is added to the 5' end.
What enzyme was most likely used to produce the molecule shown in the figure?
A restriction enzyme
A researcher needs to clone a particular DNA sequence to express the sequence and also modify the polypeptide product. Which of the following vectors would allow her to satisfy both of these requirements?
A yeast plasmid
Which of the following is true of viruses? (2 points) They must use a host cell's metabolic enzymes and pathways to obtain energy. They must use a host cell's ribosomes to synthesize proteins. They must use a host cell's nucleotides for transcription and translation.
All of the above
Which of the following statements is true about replication origins?
All of the above responses are correct.
Separating DNA fragments by gel electrophoresis is useful for which of the following?
All of the listed responses are correct.
Amylose is a form of starch made up of α glucose monomers that are bound by 1-4 linkages. How would the molecule be affected if the subcomponents were joined by 1-6 linkages instead? Explain how this might affect the function of the resulting molecule.
Amylose is a form of starch made up of glucose monomers bound by 1-4 linkages. The molecule Amylose would be geat affected if subcomponents were joined by 1-6 linkages instead. The names of these linkages refer to the carbon number of the two residues that have joined to form the bond. With 1-4 linkages, the amylose molecule is formed by unbranched chains of glucose monomers. If it had 1-6 linkages, it would be formed by branched chains of glucose monomers. So instead of showing a linear diagram of monomers, it would have some linear and some repeating up and down.
When the ribosome reaches a stop codon on the mRNA, no corresponding tRNA enters the A site. If an experimenter was able to stop the translation reaction at this point, which of the following would he be able to isolate?
An assembled ribosome with a polypeptide attached to the tRNA in the P site
A drug that prevents the shortening of microtubules would mostly affect which phase of mitosis?
Anaphase
Which of the following statements best describes how animals may become better suited, over time, to accommodate specific needs? (2 points)
Animals with mutations that create more effective structures will become more abundant.
Examine the digestive system structures in the figure below. The agents that help emulsify fats are produced in (2 points)
B (liver)
In a density-dependent population, what will most likely occur if population density decreases? (2 points)
Birthrate will increase.
A scientist is studying two previously undocumented organisms to determine how environmental conditions affect phenotype expression. In one study, the scientist determines how temperature affects the growth rate of these two organisms. The graph below depicts the data gathered by the scientist: Based on the data collected by the scientist, which of the following is the most appropriate conclusion? (2 points)
Both organisms appear to have the ability for proteins to interact with the environment. (One decreases with higher temp the other increases)
The segment of DNA shown in this figure has restriction sites I and II, which create restriction fragments A, B, and C. If these fragments were separated by gel electrophoresis, which of the following best represents the expected results?
C | A| B|
Regarding the diagram of the cardiovascular system above, which statement is true? (2 points)
Carbon dioxide concentration is greater in area 2 than in area 8.
Which of the following best describes the evolution of cell communication in organisms? (2 points)
Cell communication evolved early in the history of life because cell-signaling mechanisms are present in plants, animals, and bacteria.
Predict and explain how the chemicals released by burning fossil fuels can be absorbed by the natural cycles of the ecosystem and can affect both the local and global ecosystems. (5 points)
Chemicals released by burning fossil fuels, such as coal, petroleum or natural gas, can be absorbed by natural cycles of the ecosystem and affect both local and global ecosystems. This affects the carbon cycle especially. The carbon cycle uses four major processes: photosynthesis, respiration, combustion, and decomposition, which are all important for the regulation of the amount of carbon in the atmosphere at a time. The burning of fossil fuels releases carbon dioxide and other gases into the atmosphere. The significance of this is that these gases absorb reflected infrared radiation, and often they re-radiate some of this to earth. This phenomenon known as the greenhouse effect causes the gradual warming of the earth's overall temperature. Carbon dioxide is certainly an important part of the carbon cycle since plants use it for photosynthesis. However, the rate at which humans burn fossil fuels is very unnatural and there is too much in the atmosphere.
In the human body, where does the majority of digestion occur? (1 point)
D. Small intestine
Hershey and Chase made use of which of the following facts in their attempt to determine whether DNA or protein is the genetic material in a cell?
DNA contains phosphorus, whereas protein does not. So if tagged phosphorus is observed in offspring, it was inherited.
Which action by organisms would most likely result in an increase in the amount of atmospheric carbon? (2 points)
Decreased population of trees due to deforestation by humans
Which of the following best summarizes the relationship between dehydration reactions and hydrolysis? (2 points)
Dehydration reactions assemble polymers, and hydrolysis reactions break down polymers.
How do components of a DNA molecule influence its physical properties? (1 point)
Deoxyribose and phosphate, linked by phosphodiester bonds, form repeating units to make up the backbone of DNA.
Which of the following is NOT true regarding the signal pathway that controls gene expression within an organism?
Different kinds of cells have the same proteins.
An invasive species of insect is inadvertently introduced into two different ecosystems. Ecosystem 1 has relatively low species diversity but large populations of the existing species. Ecosystem 2 has an overall smaller number of organisms but greater species diversity. Which of the following best compares how these two ecosystems will respond to the invasive species? (1 point)
Ecosystem 2 will be more resistant because diverse species use more resources, leaving less for the invasive species.
Scientists estimate that humans have released more than 150 billion tons of carbon dioxide into the atmosphere since the 1970s. If world leaders make decisions and implement policies that reduce the global carbon dioxide footprint, predict the likely outcome on Earth's environment. (2 points)
Ecosystems could stabilize, but some biodiversity could be lost forever.
Researchers took measurements of the amount of DNA per nucleus in many cells from a growing fungus sample. The measured DNA levels ranged from 4 to 8 picograms per nucleus. In what stage of the cell cycle would the nucleus contain 8 picograms of DNA?
G2
Which of the following best explains a method by which plants use long-distance signaling to carry out cell communication?
Gas hormones are released and travel through the air to reach their target cells.
A group of students has taken samples of their own cheek cells, purified the DNA, and used a restriction enzyme known to cut at zero, one, or two sites in the particular gene of interest to the students. What steps should they follow next, in order, to compare these genes?
Gel electrophoresis to sort the fragments, then a fluorescent probe for gene sequence
What do conjugation, transformation, and transduction have in common? (2 points)
Genetic material is transferred in all three.
After telophase I of meiosis, what is the chromosomal makeup of each daughter cell?
Haploid, and the chromosomes are each composed of two chromatids.
Testosterone is a human hormone that enters cells and binds to specific proteins, which in turn bind to specific sites on the cells' DNA. These proteins most likely act to do what?
Help RNA polymerase transcribe certain genes
In the early to mid-1900s, there was considerable debate about whether protein or DNA was the hereditary material. Biologists understood that chromosomes segregated to opposite poles in mitosis and that the chromosome number was halved in meiosis. They also knew that chromosomes were made of both protein and DNA. Summarize the Hershey-Chase experiment and explain how the results supported the idea that DNA was the hereditary material.
Hershey & Chase studied a bacteriophage that was composed of a DNA core and a protein coat. The two scientists wanted to determine which part of the virus entered the bacterial cell so they grew viruses in cultures containing radioactive isotopes of phosphorus-32 and sulfur-35. The 32P (phosphorus) was used in the Hershey-Chase experiment because phosphorus is present in DNA but not in protein. These markers (P-35 and S-35) told the scientists which molecules actually entered the bacteria and carried the genetic information of the virus. They concluded the genetic material of the bacteriophage was DNA, not protein. Hershey and Chase's experiment confirmed Oswald Avery's earlier results, convincing many scientists that DNA was the genetic material found in genes-- not just in viruses and bacteria, but in all living cells.
Which of the following is a negative impact human beings have on the carbon cycle? (2 points)
Human beings increase the amount of carbon dioxide in the atmosphere.
How do amino acid sequences influence the properties of a protein? (2 points)
Hydrogen bonding between every fourth amino acid results in formation of an α helix.
Researchers have isolated DNA from three different cell types in the same organism. They determined the relative DNA content for each cell type and plotted the results on the graph shown in the figure. Which sample of DNA is the most likely to be from a nerve cell arrested in G0 of the cell cycle?
I only
How can transposable elements promote functional genetic diversity in a population? (2 points) I. Insertion into a regulatory sequence may alter the strength of transcription. II. Insertion into an intro may provide an alternative splice site, producing a protein with a new exon. III. Insertion into an mRNA strand may change the amino acid sequence produced.
I. Insertion into a regulatory sequence may alter the strength of transcription. II. Insertion into an intro may provide an alternative splice site, producing a protein with a new exon.
The figure below depicts changes in the DNA content of a recipient cell engaged in conjugation with an Hfr cell. Hfr cell DNA begins entering the cell at Time A. A fragment of the recipient's chromosome is replaced with a homologous fragment from the Hfr cell's DNA. Which two processes are responsible for the shape of the curve at Time B? (2 points) I. Transduction II. Entry of single stranded Hfr DNA III. Rolling circle replication of single stranded Hfr DNA IV. Activation of DNA pumps in the plasma membrane
II. Entry of single stranded Hfr DNA III. Rolling circle replication of single stranded Hfr DNA
Why is it ineffective to treat a viral disease with antibiotics? (2 points) I. Pathogenic RNA viruses have a high rate of mutation, quickly developing antibiotic resistance. II. Excessive antibiotic use has resulted in most viruses evolving to be insensitive to antibiotic treatments. III. Antibiotics inhibit enzymes specific to bacteria and have no effect on the enzymes encoded by viruses.
III. Antibiotics inhibit enzymes specific to bacteria and have no effect on the enzymes encoded by viruses.
The "universal" genetic code is now known to have some exceptions. Which of the following, if true, would serve as one such exception?
If UGA, which is usually a stop codon, is found to code for an amino acid in some organisms
Radish plants may have red, purple, or white flowers. A cross between a red-flowered plant and a white-flowered plant yields all-purple offspring.The flower color trait in radishes is an example of which of the following?
Incomplete dominance
A scientist wants to determine if a newly discovered species exchanged information with other members of the species about the location of a food source. The scientist collected the following data:© 2012 FLVSAnalyzing the data, which of the following would best explain how the organisms appear to communicate or not communicate with one another?
Individual members of the species look for the food; when they find it, they communicate the location of it to other members of the species.
Which of the following, when taken in by the cell, binds to the repressor so that the repressor can no longer bind to the operator?
Inducer
After an RNA molecule is transcribed from a eukaryotic gene, what are removed and what are spliced together to produce an mRNA molecule with a continuous coding sequence?
Introns are removed and exons are spliced together.
A cell has completed the first meiotic division and is just beginning meiosis II. Which of the following best describes its contents?
It has half the amount of DNA as the original cell that began meiosis.
Figure: Carbon with Hydogen, and at the end an oxygen and hydroxide
It is an unsaturated fatty acid, and molecules of this type are usually liquid at room temperature.
What is true of an X-linked gene but not of a Y-linked gene?
It is present in both male and female offspring.
Genomic imprinting generally occurs due to the addition of methyl groups to C nucleotides in order to silence a given gene. If this depends on the sex of the parent who transmits the gene, which of the following must be true?
Methylation must be reversible in ovarian and testicular cells.
A molecule with the formula C18H36O2 would probably exhibit which of the following characteristics? (2 points)
Molecules with this formula would likely be hydrophobic.
Which of the following best describes how the nervous system in an animal transmits information to produce a response? (2 points)
Motor neurons carry signals from the central nervous system to muscle cells to cause contractions.
Which of the following does NOT explain a process involved in detection of internal and externals by the central nervous system? (2 points)
Motor neurons transmit signals from sensory neurons to the brain or ganglia.
Which of the following statements is correct regarding prokaryotic genetics? (2 points)
Mutations in the DNA are a primary source of variation in prokaryote populations.
Which of the following statements best compares genetic diversity in eukaryotes and prokaryotes?
Mutations increase the genetic diversity in both prokaryotes and eukaryotes.
A mutation in a gene causes an alteration in the structure of helicase. Which of the following would you expect as a result of this mutation?
No replication fork will be formed.
Which of the following does NOT describe the signal molecule in this model? (2 points)
Once the signal is released, the gate is permanently closed.
Imagine that an error in transcription alters the formation of one single tRNA molecule within a cell. The altered tRNA still attaches to the same amino acid, but its anticodon loop has a different sequence, which binds to a different mRNA codon. What will be the effect on translation in this cell?
One altered tRNA molecule will be relatively inconsequential because it will compete with many "normal" ones.
If a person had a small hole in his heart between the left and the right ventricles, what would the most likely consequence be? (1 point)
Oxygen content would be decreased in the systemic circuit.
How would an increase in precipitation most likely affect organisms in a terrestrial ecosystem? (2 points)
Primary production would increase.
Explain how the rapid reproduction of many prokaryotic organisms contributes to genetic variations within the population. (5 points)
Prokaryotes reproduce asexually through the process of binary fission. This process involves duplicating the chromosomes and splitting the cell into two. Because prokaryotes can reproduce very fast, there is a higher chance of genetic variation. New mutations can increase genetic diversity quickly in species with short generation times and large populations. The Genetic recombination of DNA from two sources can be carried out by one of three different mechanisms: transformation, transduction, and conjugation. The process of Horizontal Gene Transfer occurs if the movement of genes from one organism to another is from members of different species. Thus, horizontal gene transfer increases genetic diversity by moving genes across species by introducing new genes into genomes.
A group of students decide to repeat the Hershey and Chase experiment with modifications. They decide to radioactively label the nitrogen in the DNA, instead of the phosphate. They reasoned that each nucleotide contains more nitrogen than phosphate, so labeling the nitrogen will provide a stronger signal than labeling the phosphate. What is the flaw in this experimental design?
Proteins also contain nitrogen, so the radioactivity would not distinguish between DNA and proteins.
According to the data obtained by the researcher, predict what will happen when the organism is exposed to a strong acid of pH 2? (2 points)
RNA polymerase will be bound to the promoter. (The concentration of th active repressor is high at 11/12)
Which of the following explains how genetic variation increases in a population? (2 points)
Recombination during sexual reproduction
Allergic reactions include runny nose and watery eyes. Doctors can prescribe antihistamine drugs that can prevent or decrease the effects of an allergic reaction. Which of the following does NOT explain how antihistamine drugs help prevent or decrease the effects of an allergic reaction? (2 points)
Reducing the concentration of histamine outside of the target cell
A scientist needs to make complementary DNA (cDNA) from RNA. Which of the following would she use?
Reverse transcriptase
Transcription in eukaryotes requires which of the following in addition to RNA polymerase?
Several transcription factors (TF's)
Which is a benefit of single-celled organisms that is not shared by multicellular organisms? (2 points)
Single-celled can adapt more quickly to their environment.
Cells can use different types of signaling to achieve different goals. Which of the following best describes hormonal signaling in animals? (2 points)
Specialized cells release hormone molecules into the circulatory system, allowing distant target cells to be affected.
Scientists construct an experimental bacteriophage that is composed of the T2 phage protein coat and T3 phage DNA. If a bacterium is infected by this phage, the new phages produced would be expected to have
T3 protein and T3 DNA
One strand of a DNA molecule has the base sequence 5'-ATAGGT-3'. The complementary base sequence on the other strand of DNA will be 3'-_____-5'.
TATCCA
A researcher has altered the 3' end of the tRNA corresponding to the amino acid methionine in such a way as to remove the 3' AC. Which of the following describes the most likely result of this change?
The amino acid methionine will not bind.
How does the sequence of the RNA components highlighted above affect its properties? (2 points)
The base sequence determines which amino acids will be produced from RNA.
Within a strand of RNA, nucleotides can contain one of four different nitrogenous bases. What is the impact of this variation in nitrogenous bases? (2 points)
The bases arrange themselves into codons consisting of three bases, with each codon producing a unique amino acid.
Which of the following best describes how the brain functions in coordinating movement in vertebrates? (2 points)
The cerebellum receives sensory information about joints and muscles and integrates it.
Using the following data table and equation, what is the conversion efficiency for eggs? (2 points)
The conversion efficiency for eggs is approximately 37%
The graph below shows the concentration of the reactants and products over time for a biochemical reaction that is catalyzed by an enzyme. Which diagram best illustrates how the reaction would be affected if a competitive inhibitor that binds to the enzyme was introduced?
The difference between the red and blue line just decreases a little making it skinnier.
Which of the following best explains why an "exotic" species introduced into a new ecosystem often outcompetes the native species and forms a viable niche for itself? (2 points)
The exotic species has few predators to slow its reproduction in the new environment.
A scientist is studying the evolutionary passage of animal behavior. The scientist performed an experiment that placed a single injured minnow in a group of minnows. The data records show that all of the healthy minnows in the group move away very quickly. After reading the article, which of the following is the best conclusion regarding this behavior? (2 points)
The injured fish most likely releases a physiological trigger that initiates the response.
Which of the following would provide the best evidence to support the claim that the introduction of an invasive species affects the stability of the ecosystem over a long period of time? (1 point)
The invasive species would displace native species by outcompeting for resources, causing a decrease in species diversity and ecosystem stability.
The enzyme lactase catalyzes the digestion of the milk sugar lactose. In our human ancestors, lactase was only produced during infancy. Today, a significant portion of the adult human population can digest lactose while the other adults remain lactose intolerant. What is a likely cause of this variation? (1 point)
The lactose-tolerant adults have point mutations in the regulatory DNA of their lactase genes.
How do the leading and lagging strands differ?
The leading strand is synthesized in the same direction as the movement of the replication fork, while the lagging strand is synthesized in the opposite direction.
In an experimental situation, a student removes the 5' cap and poly-A tail from an mRNA molecule before inserting it into a eukaryotic cell. Which of the following would you expect to occur as a result of these modifications?
The molecule is digested by exonucleases because it is not protected at the 5' end.
A scientist claims plants can communicate with each other in a variety of ways. Justify the claim of the scientist and describe the types of responses that result from the communication of two different plants. (5 points)
The scientist is correct, plants can communicate with each other in a variety of ways. Like any animal, plants create chemical signals from environmental stimuli and can share these chemical signals with each other. This can occur via the air or the soil they grow in. This may come in handy for example when plants are under attack. In the air, plants release odorous chemicals called volatile organic compounds (VOCs). When lawns are mowed, this is what causes the smell of freshly cut grass. In the soil, plants communicate with each other by emitting soluble chemicals into the rhizosphere, which transports them through networks formed by soil fungi.Most long-distance signaling in plants and animals occurs through the secretion of hormones. Because plants do not have circulatory systems, many of their hormones are released as gases into the air to be recognized and detected by the target cells. An example of this could be the plant hormone Ethylene which helps regulate growth and promotes the ripening of fruit. This molecule is released as a gas and it is small enough to pass through cell walls.
Which of the following is NOT a major scientific theory that helps explain how ecosystems have changed on Earth due to large-scale events? (2 points)
The vast majority of extinctions are caused by human impact.
Which of the following best describes how a change in an environmental factor will affect the phenotype of hydrangeas? (1 point)
Their flowers will turn pink when treated with calcium carbonate.
Two siblings are identical twins but are exposed to different environmental factors. Which of the following best explains the long-term effect of environmental influences on identical twins? (1 point)
Their genotypes will be expressed differently, resulting in different phenotypes.
Unequal crossing over during prophase I can result in one sister chromosome with a deletion and another with a duplication. A mutated form of hemoglobin in humans, called hemoglobin Lepore, has a deleted series of amino acids. If this mutated form was caused by unequal crossing over, what would be an expected consequence?
There are also individuals whose hemoglobin contains two copies of the amino acids deleted in hemoglobin Lepore.
Which of the following best describes cell communication processes that are present in bacteria, yeast, and multicellular organisms? (2 points)
They release chemical messengers to communicate with cells they may or may not be in direct contact with.
A mutation causes some of an animal's target cells to form without receptors for local regulators. What is most likely to happen to the affected target cells based on this error? (2 points)
They will not be able to multiply in response to growth factors given off from nearby cells.
Which of the following is a function of a signal peptide?
To translocate polypeptides across the ER membrane
Which of the following is a true statement about the competitive exclusion principle? (2 points)
Two species cannot occupy the same niche.
Describe how a virulent virus (one that lyses a cell, never becoming recombinant) adds to host-cell genetic variation through the process of natural selection. (5 points)
Viruses tend to evolve faster than their host cells. Natural selection occurs based on genetic variation. Natural selection results in the accumulation of genetic variations favored by the environment. Viruses gain genetic variation in two ways: recombination (viruses exchange parts of DNA or RNA) and random mutation. Recombination normally occurs when two viruses infect the same cell. Mutations are permanent changes in the genetic material. Natural selection favors bacterial mutants with surface proteins that are no longer recognized as receptors by a particular type of phage. Transduction results in a recombinant being formed. In transduction, bacteriophages carry prokaryotic DNA from one cell to another. This usually occurs as a result of errors in the virus's replicative cycle.A recombinant cell will be formed if some of the prokaryotic DNA carried by the phage is incorporated into the host cell's chromosome. Transduction can happen through either the lytic cycle or the lysogenic cycle. A virulent virus that lyses a cell involves the Lysogenic cycle, which is a type of phage replicative cycle in which the viral genome becomes incorporated in the bacterial host chromosome as a prophage is replicated along with the chromosome and does not kill the host. The fitness of the host is bound to the fitness in vertical transmission but is not so bound in horizontal transmission. Horizontal transmission is another name for Horizontal Gene Transfer, which occurs if the movement of genes from one organism to another is from members of different species. While vertical gene transfer is the transfer of genetic material from parents to offspring through sexual or asexual reproduction. For these reasons, the virulent virus influences the natural selection of host cells.
Nucleotides can be radio labeled before they are incorporated into newly formed DNA and can therefore be used to track their incorporation. A research team used labeled T nucleotides and introduced them into a culture of dividing human cells at specific times during the division. Which of the following questions might be answered by this experimental method?
What is the length of the S phase of the cell cycle?
Which factors of the island equilibrium model would produce the greatest amount of species richness on an island? (2 points)
a large island that is near the mainland
In cats, black fur color is caused by an x-linked allele while the other allele at this locus causes orange color. The heterozygous allele is tortoiseshell. Normally only females have the tortoiseshell phenotype because
a male inherits only one allele of the X-linked gene for hair color
A biological polymer that carries genetic information has monomers that consist of a five-carbon sugar, a nitrogenous base, and (2 points)
a phosphate
A series of enzymes catalyze the reaction X → Y → Z → A. Product A binds to the enzyme that converts X to Y at a position remote from its active site. This binding decreases the activity of the enzyme. With respect to the enzyme that converts X to Y, substance A functions as (2 points)
an allosteric inhibitor
Different types of selection may occur within a species in response to environmental change. Which of the following would provide evidence that stabilizing selection is occurring in response to environmental conditions? (1 point)
an increase in the frequency of intermediate phenotypes and a decrease in the frequency of extreme phenotypes
In a series of mapping experiments, the recombination frequencies for four different linked genes of the Drosophila fly were determined as shown in the figure. Based on this information, what is the most probable order of these genes on the chromosome?
b-rb-cn-vg
Which of the following evolutionary mechanisms occurs when a small group of individuals survives after a catastrophic event, and the gene frequencies may NOT reflect those of the former population? (2 points)
bottleneck effect
Human beings have disrupted the sulfur cycle by (2 points)
burning coal to produce power
Which of the following has been conserved for use in both plant and animal evolution?
cell junctioning
The signaling pathway shows how different molecules act as second messengers to bring about a cellular response. Based on this model, which of the following causes a decrease in cellular response?
closing of IP3-gated calcium channels
The anticodon of a particular tRNA molecule is
complementary to the corresponding mRNA codon
Ammonia, NH3, is used in numerous industrial processes, including the production of pharmaceuticals such as sulfonamide and antimalarials and vitamins such as the B vitamins. The equilibrium equation for the synthesis of ammonia (sometimes known as the Haber process) isN2(g) + 3H2(g) ↔ 2NH3(g)What would happen to the rate of the forward reaction if the concentration of nitrogen were decreased? The reaction rate would
decrease because there is less opportunity for molecular collisions
Which of the following plant structures is correctly paired with its function? (2 points)
dermal tissue/protects against pathogens and drought while aiding in absorption of nutrients
A scientist observing a specific population over a long period of time notices a shift in the population's frequency curve from an intermediate phenotype to an extreme phenotype. What is the best explanation for this observation? (2 points)
disruptive selection is creating a shift in phenotypes due to environmental conditions
The trend depicted by this diagram can best be described as which of the following? (1 point)
disruptive selection, which occurs as environmental conditions favor phenotypic extremes over intermediate phenotypes
What type of covalent bond between amino acid side chains (R groups) functions in maintaining a polypeptide's specific three-dimensional shape? (2 points)
disulfide bond
After eukaryotic transcription occurs, mRNA undergoes several modifications before leaving the nucleus to take part in translation. One modification involves the cutting out of nonessential sections of mRNA and splicing together the remaining sections of mRNA necessary for translation. Which of the following mRNA sections are spliced together into the finished RNA molecule?
exons
What type of receptor is described in the following paragraph? (2 points)This type of receptor works with the help of a protein that binds the energy-rich GTP molecule. The protein then binds to an enzyme, temporarily altering the enzyme's shape so it can trigger the next step in signaling for the necessary cellular response.
g protein-coupled receptor
In general, the frequency with which crossing over between two linked genes depends on what?
how far apart they are on the chromosome
To increase the effectiveness of exchange surfaces lining the lungs and the intestines, evolutionary pressures have (2 points)
increased the exchange surface area with folds and branches
A scientist studied the composition of several different organs in a mouse to determine if some organs contain different concentrations of mitochondria. The data below show the findings of the scientist: Based on the data from the scientist, what is the best prediction of the mitochondria composition of the mouse's appendix? (2 points)
less than the liver
The diagram represents synaptic signaling in an animal. Which of the following is being released into the synapse in this model?
neurotransmitters
The monomers, or small units, used in the synthesis of DNA molecules are called
nucleotides
Professor Jamey Marth at the University of California, Santa Barbara, identified 70 molecules that are used to build cellular macromolecules and structures. These include at least 34 saccharides, 8 nucleosides, and 20 amino acids. In theory, which class of biological polymer has the greatest information-coding capacity? (2 points)
polysaccharides
Referencing the model, what determines if the cell should stop transcribing mRNA? (2 points)
presence of hormones outside of the cell
An epithelial cell with a relatively large amount of cilia probably has what function? (2 points)
propelling mucous in a particular direction
What is the correct identification of No. 3 if the blood is entering the heart from the lungs? (2 points)
pulmonary veins
Below is a diagram illustrating how cells at the bottom of the early embryo are releasing chemicals to nearby cells:What is the primary function of the signaling molecule?
regulating gene expression
The proportion that each species represents of all the individuals in a community is an important factor that influences the stability of an ecosystem. Which of the following terms does this describe? (1 point)
relative abundance
Yeast cells, plant cells, and mammal cells all share many similarities in cell signaling. This provides evidence that
signal transduction pathways appeared in cells before the evolution of multicellular organisms
What type of epithelial tissue, found in the intestines, absorbs nutrients? (2 points)
simple columnar epithelium
The type of selection that favors intermediate phenotypes of a species over extreme phenotypes due to a change in environmental conditions is known as which of the following? (1 point)
stabilizing selection
Which of the following is correctly matched with its tissue system? (2 points)
stele/vascular tissue system
A common feature of starch and glycogen is that molecules of both (2 points)
store energy for use by living organisms.
In the example, no RNA is made during the process. What would need to occur for lacZ to be expressed in mRNA?
unbinding the active repressor from the operator
An invertebrate organism raised in a sterile environment begins to show signs of a viral infection. What is the most likely explanation of how this infection was acquired by the organism?
vertical transmission from a parent
Viruses that break open the host cell to releases phages at the end of the replicative cycle are called
virulent phages