rip AP Bio Tri 2
Evolution biologists have observed variation in the average age and size of mature individuals in a population of small freshwater guppies. Guppies found in pools with pike cichlids-- a predator fish that preys primarily on larger guppies-- reproduce at a young age and are small at maturity. Guppies found in pols with killifish-- a different predator fish that preys primarily on smaller guppies-- reproduce at an older age and are larger at maturity. Which of the following predicts the most likely outcome of moving a population of guppies from a pool with pike cichlids to a pool with killifish
** After many generations, the offspring of the introduced guppies will mature at an older age and larger size because of selective pressure from the new predator
A species of snail lives in the intertidal zone along the coast of New England. The dark-colored variety of the species is more common in northern New England, the light-colored variety is more common two hundred miles away in southern New England, and both varieties are commonly found in central New England. Which of the following best explains the observed distribution pattern of the snails
** Dark-colored snails absorb more solar energy and so survive more readily in colder northern waters
Gene expression might be altered at the level of post-transcriptional processing in eukaryotes rather than prokaryotes because of which of the following
** Eukaryotic exons may be spliced in alternative patterns
Some cells release active signaling proteins when membrane-bound precursor proteins are cleaved by proteolytic enzymes. The signaling proteins then can bind to receptors on the surface of a target cell, thereby activating an intracellular signaling pathway and eliciting a response from the target cell. The mechanism of activation 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.
** If a proteolytic enzyme from one species is incubated with a precursor protein from another species, does correct cleavage occur
Gregor Mendel's pioneering genetic experiments with pea plants occurred before the discovery of the structure and function of chromosomes. Which of the following observations about inheritance in pea plants could be explained only after the discovery that genes may be linked on a chromosome.
** Most offspring of a given cross have a combination of traits that is identical to that of either one parent of the other
Malaria is caused by several different species of Plasmodium, a protozoan parasite. Plasmodium resistance to the common drugs used to treat malaria has increased in recent years. In a scientific study, Plasmodium samples were analyzed in blood drawn from a large number of infected patients before drug treatment and subsequently from the subset of infected patients with drug-resistant Plasmodium. DNA sequences of four different Plasmodium genes thought to be involved in resistance were compared between samples from patients with drug-sensitive Plasmodium and patients with drug-resistant Plasmodium. Which of the following best supports the hypothesis that preexisting mutations confer drug resistance
** Some of the mutations that occur most frequently in samples from patients treated with antimalarial drugs are detectable in Plasmodium samples collected prior to use of antimalarial drugs
Freshwater bony fish secrete large volumes of very dilute urine. Many marine bony fish secrete small volumes of concentrated urine. Which of the following best explains the differences in nitrogenous-waste excretion between freshwater and marine bony fish
** The differences arose during divergence, as fish from a common ancestor faced different selective pressures in environments of different osmolarity
The following DNA sequence is a small part of the coding strand from the open reading frame of B-hemoglobin gene. Given the codon chart, what would be the effect of a mutation that deletes the G at the beginning of the DNA sequence 5'-- GTTTGTCTGTGGTACCACGTGGACTGA-- 3'
** The reading frame of the sequence would shift, causing a change in the amino acid sequence after that point
In a species that has five different alleles for a gene at a particular locus, how many different alleles may be present in the somatic cells of one diploid individual
** Two
Rates of adaptive radiation typically are at their highest in which of the following situations
** When new niches become available
In both eukaryotes and prokaryotes, gene expression is primarily regulated at the level of
** transcription
A certain species of plant has four unlinked genetic loci, W, X, Y, Z. Each genetic locus has one dominant allele and one recessive allele. For a plant with the genotype WwXxYyZz, what is the probability that the plant will produce a gamete with a haploid genotype of Wxyz
1/16
A couple has 5 children, all sons. If the woman gives birth to a sixth child, what is the probability that the sixth child will be a son
1/2
Cytosine makes up 38% of the nucletides in a sample of DNA from an organism. Approximately what percentage of the nucleotides in this sample is thymine
12
Insulin is a protein that is made up of 51 amino acids. It would have been translated from an mRNA transcript that had at least
153 nucleotides
Which of the following sequences of nucleotides are possible in the template strand of DNA that would code for the polypeptide sequene Phe-Leu-Ile-Val
3'-AAA-GAA-TAA-CAA-5'
Black fur in mice (B) is dominant to brown fur (b). Short tails (T) are dominant to long tails (t). What fraction of the progeny of the cross BbTt x Bbtt will have black fur and long tails
3/8
How many unique gametes could be produced through independent assortment by an individual with the genotype AABbCCDdEE
4
See pedigree in test One of the affected males from the third generation has a child with a female who is a carrier. For the pedigree shown above, which of the following best expresses the probability that the couple's first son will be affected with the disorder
50%
How many different genotypes are possible from the cross of AaBb x AaBb
9
A biologist spent many years researching the rate of evolutionary change in the finch populations of a group of islands. It was determined that the average beak size of finches in a certain population increased dramatically during an intense drought between 1981 and 1987. During the drought, there was a reduction in the number of plants producing thin-walled seeds. Which of the following best describes the mechanism behind the change in beak size in the finch population
A change in gene frequencies in the finch population due to selective pressure from the environmental change
Which of the following is characteristic of the lytic cycle
A large number of phages is released at a time
The Stanley Miller apparatus demonstrated that organic molecules could assemble spontaneously in an environment lacking free oxygen and containing water, methane, and ammonia in the presence of an abundant energy source, such as an electric discharge. The research was considered supportive of the organic soup hypothesis, which states that the primitive atmosphere provided inorganic precursors from which organic molecules could have been synthesized in the presence of an energy source. Based on the subsequent research, the primordial atmosphere was determined to contain less methane and more carbon dioxide. The new data about the composition of the early atmosphere had which of the following effects on the origin-of-life hypothesis
A new organic soup hypothesis was proposed to account for the new data about the atmosphere
Sickle-cell anemia is associated with a mutation in the gene encoding the beta subunit of hemoglobin that results in a change from glutamic acid to valine at position six. All other amino acids are identical to a normal hemoglobin molecule. Based on the information above, which of the following mutation is the likely cause of sickle-cell anemia
A single base-pair substitution in the gene encoding the beta subunit
Some strains of the bacterium Streptococcus Pyogenes secrete poisonous substances called exotoxins. The genes encoding the exotoxoins are thought to have originated in bacteriophages, which are viruses that infect bacteria. Which of the following is the most likely mechanism by which the Streptococcus Pyogenes acquired the ability to produce the exotoxins
Bacteriophage DNA became integrated in the bacterial chromosome
Ciprofloxacin is given as an antibiotic to healthy livestock to promote efficient weight gain. Strains of the bacterium Campylobacter jejuni naturally colonize the digestive tracts of livestock, and the Campylobacter jejuni can be transferred to people through the ahndling and consumption of contaminated meat. People infected with Campylobacter jejuni also are treated with ciprofloxacin. Which of the following is the most likely consequence of adding ciprofloxacin
Ciprofloxacin-resistant strains of Campylobacter jejuni will have a selective advantage in the digestive tracts of livestock, increasing the risk of serious infections in people
Lobe-fined fishes were present in the oceans of the world approximately 400 million years ago. The first tetrapods date to about 365 million years ago. One hypothesis states that early tetrapods evolved from lobe-finned fishes. Which of the following is the best plan for testing the hypothesis
Comparing the arrangements of bones in the fins of lobe-finned fishes and limbs of the earliest tetrapods
Bacteriophages are viruses that infect bacteria. In an experiment, bacteriophages were labeled with either radioactive phosphorous or radioactive sulfur. The labeled bacteriophages were incubated with bacteria for a brief amount of time and then removed. The infected bacteria cells were found to contain significant amounts of radioactive phosphorous but not radioactive sulfur. Based on the results of the experiment, which of the following types of molecules did the bacteriophages most likely inject into the bacterial cells
DNA
Which of the following removes the RNA nucleotides from the primer and adds equivalent DNA nucleotides to the 3' end of Okazaki fragments
DNA polymerase I
What is the enzyme used to position nucleotides during DNA replication
DNA polymerase III
The genetic code is essentially the same for all organisms. From this, one can logically assume all of the following except
DNA was the first genetic material
Which of the following can be diagnosed by examining a karyotype of an individual's white blood cells
Down syndrome
A child is born with blood type A to a mother with blood type B. The father must have which of the following blood types
Either AB or A
The fossils in a layer of rock are significantly different from those in the rock layer directly above it. One hypothesis to explain the difference is that a major extinction event occurred at the point in time represented by the transition between the two rock layers. Which of the following is the best plan for collecting data to use in a test of the hypothesis
Examining the upper part of the lower rock layer for evidence of a catastrophic event, such as the presence of shocked quartz, iridium, or soot particles
A biologist spent many years researching the rate of evolutionary change in the finch populations of a group of islands. It was determined that the average beak size of finches in a certain population increased dramatically during an intense drought between 1981 and 1987. During the drought, there was a reduction in the number of plants producing thin-walled seeds. Which of the following statements might best explain the increase in average beak size in the finch population during the drought
Finches with bigger beaks are better able to crack thick-waled seeds and produce more surviving offspring
Eukaryotic telomeres replicate differently than the rest of the chromosomes. This is a consequence of which of the follwoing
Gaps left at the 5' end of the lagging strand because of the need for a 3' onto which nucleotides can attach
Pattern 1 (Gene A-- Inactive)(Gene B-- Inactive)(Observation-- No neurons develop) Pattern 2 (Gene A-- Inactive)(Gene B-- Active)(Observation-- No neurons develop) Pattern 3 (Gene A-- Active)(Gene B-- Inactive)(Observation-- Greater-than-normal number of neurons develop) Pattern 1 (Gene A-- Active)(Gene B-- Active)(Observation-- Normal number of neurons develop) Which of the following claims is best supported by the data
Gene a promotes neuron development; gene B promotes programmed cell death in neuronal precursors
A student in a biology class crossed a male Drosophila melanogaster having a gray body and long wings with a female Drosophila melanogaster having a black body and apterous wings. The following distribution of traits was observed in the offspirng: Gray body, long wings-- 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
Genes for the two traits are located close together on the same chromosomes, and crossing over occurred between the two gene loci
Which of the following best supports the claim that organisms of different domains share a common ancestor
Glycolysis occurs in both prokaryotic cells and eukaryotic cells
Hydrangea macrophylla is a species of plant with blue or pink flowers. Flower color in Hydrangea macrophylla plants is thought to be determined primarily by soil conditions rather than by inherited differences. Which of the following will provide the most direct evidence that flower color in Hydrangea macrophylla is due primarily to soil conditions
Growing cuttings from the same Hydrangea macrophylla plant under controlled conditions that vary only with regard to soil pH
What is the enzyme used to unwind and unzip DNA
Helicase
On a large volcanic island, researchers are studying a population of herbaceous plants. Which of the following observations best supports the prediction that speciation will occur within the existing plant population
Lava has separated the population into two areas: an upland forest and a lowland marsh
Methicillin-resistant Staphylococcus aureus can be a serious threat to human health. There is evidence that Staphylococcus aureus infections are common in hospitals and that MRSA have become resistant to other antibiotics besides methicillin. This suggests that the rapid evolution of resistance in the bacteria poses a serious public-health challenge. Which of the following best explains the ability of MRSA to evade existing drug therapies
MRSA exchange genetic material with other antibiotic-resistant bacteria, which spread resistance in the Staphylococcus aureus population
Why are males more often affected by sex-linked traits than females
Males have only one copy of the X chromosome
5'-- GACCGCAUGGUGACGAAAUUUGGCCAUUAA-- 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 first available start codon
Met- Val- Thr- Lys- Phe- Gly- His
Which of the following occurs in all species of living organisms and may lead to an increase in genetic variation
Mutations in the genome
The pesticide DDT was widely used in the 1940s as a method of insect control. In the late 1950s the first DDT-resistant mosquitoes were discovered, and eventually DDT-resistant mosquitoes were found globally. When DDT is used now, the development of DDT resistance in mosquito populations occurs in months rather than years. Which of the following best explains the observations concerning DDT resistance in mosquitoes
Natural selection favors DDT-resistant mosquitoes that are already present in a population when DDT exposure occurs
DNA--> Pre-mRNA--> mRNA--> Protein Which of the following best describes an even during step 2 in the simplified model above
Noncoding sequences are removed from a newly synthesized RNA molecule
Which of the following best describes the parents in a test cross
One individual has the dominant phenotype and the other has the recessive phenotype
Within a forest ecosystem, there is a large amount of diversity among members of a warbler species. Of the following stages of meiosis illustrated for a typical cell, which contributes most to diversity among the warblers
Prophase 1
In eukaryotes, there are several different types of RNA polymerase. Which type is involved in transcription of mRNA for a globin protein
RNA polymerase II
For a repressible operon to be transcribed, which of the following must occur
RNA polymerase must bind to the promoter, and the repressor must be inactive
What is the process in which naked DNA is taken up by bacterial or yeast cells
Reverse transcription
Review Problems 18-20 from Test
Review Problems 18-20 from Test
Review Problems 28-31 from Test
Review Problems 28-31 from Test
Review Problems 29-32 from Test
Review Problems 29-32 from Test
Eye pigment in a particular strain of fly is determined by two genes. An autosomal gene that controls the color of pigments in the eye has two alleles: a dominant allele (R) that results in red eyes and a recessive allele (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. Individuals without a T allele have white eyes regardless of the alleles of the other eye-color genes. Which of the following represents a cross between a white-eyed female and a red-eyed male
RrX^tX^t x RrX^TY
A student analyzed a viral genome and found that the genome had the following nucleotide composition: 28% adenine, 20% thymine, 35%, cytosine, 17% guanine Which of the following best describes the structure of the viral genome
Single-stranded DNA
IN the "RNA world" model for the origin of life, the first protocols relied on RNA, not DNA, for information storage and transmission. Which of the following could best be considered evidence in support of the RNA world model
Some RNA molecules in contemporary cells have catalytic function
What is the enzyme used to extend telomeres
Telomerase
Cross 1-- Blue Male x Blue Female (60 blue males, 52 white males, 124 blue females, 0 white females) Cross 2-- Blue Male x White Female (0 blue males, 108 white males, 115 blue females, 0 white females) Cross 3-- White Male x Blue Female (48 blue males, 53 white males, 42 blue females, 49 white females) 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.
The allele for blue is an X-linked dominant allele because there are no blue male offspring in cross 2
The bacterium Vibrio Cholerae is harmless unless a lysogenic bacteriophage provides the gene coding for the cholera toxin, which converts the bacterium to the virulent form that causes cholera. Which of the following best explains how the gene encoding cholera toxin becomes part of the bacterial genome
The bacteriophage inserts the toxin gene into the host cell DNA, and the gene is expressed with the rest of the host cell's cenes
A biologist spent many years researching the rate of evolutionary change in the finch populations of a group of islands. It was determined that the average beak size of finches in a certain population increased dramatically during an intense drought between 1981 and 1987. During the drought, there was a reduction in the number of plants producing thin-walled seeds. Which of the following procedures was most likely followed to determine the change in beak size
The beak size in a large number of finches was measured every year from 1981 to 1987
Humans ahve 23 pairs of chromosomes, and chimps have 24 pairs of chromosomes. What is the most likely explanation for these differences in human and chimp genomes
The common ancestor of humans and chimps had 24 pairs of chromosomes. During human evolution, two human chromosomes fused end to end
The diagram above depicts a karyotype of an individual human (there are two X chromosomes and one Y chromosome). Which of the following statements concerning the karyotype in the diagram is true
The diagram illustrates the results of nondisjunction during gamete formation
A biologist spent many years researching the rate of evolutionary change in the finch populations of a group of islands. It was determined that the average beak size of finches in a certain population increased dramatically during an intense drought between 1981 and 1987. During the drought, there was a reduction in the number of plants producing thin-walled seeds. The biologist discovered that from 1988 to 1993, the average beak size declined to pre-1981 levels. The reversal in beak size from 1988 to 1993 was most likely related to which of the following events
The end of the drought
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 again 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
The field was composed primarily of light-colored soil and little vegetation, affording gray mice protection from predators
In Drosophila melanogaster the allele 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 wings 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. Expected BbVv-- 862, bbvv-- 862, Bbvv-- 862, bbVv--862 Observed BbVv-- 1447, bbvv-- 1416, Bbvv-- 309, bbVv-- 277
The genes for body color and wing shape are located close to each other on the same chromosome
Why is sequencing of eukaryotic genomes more difficult than sequencing genomes of bacteria or archaea
The large size of eukaryotic genomes and the large amount of eukaryotic repetitive DNA make sequencing difficult
In animals, the hox genes encode a family of transcription factors that are important for proper development of embryonic segments and are widely conserved in organisms. The figure below shows the embryonic segments in which one such gene, Hoxc6, is expressed in the embryo of a mouse, a chick, and a goose. Embryonic segments are counted from the anterior end. During the formation of vertebrae, the most anterior embryonic segment that expresses Hoxc6 marks the end of the cervical vertebrae and the beginning of the thoracic vertebrae. All mammals have seven cervical vertebrae. Mouse (7 No Hoxc6 Expressed, 13 Hoxc6 Expressed) Chick (14 No Hoxc6 Expressed, 7 Hoxc6 Expressed) Goose (17 No Hoxc6 Expressed, 8 Hoxc6 Expressed) Which of the following statements is most likely to be true
The most anterior expression of Hoxc6 is the eight vertebra in mammals
In humans, red-green color blindness is a sex-linked recessive trait. If a man and a woman produce a color-blind son, which of the following must be true
The mother carries the allele for color blindness
The cells lining the respiratory tract of pigs have receptors for both avian and human influenza viruses. Based on the model above, which of the following best describes the origin of the new strain of human influenza virus
The new viral strain inherited a mixture of genetic material from both the avian influenza virus and the human influenza virus
Which of the following provides the strongest evidence that prokaryotes evolved before eukaryotes
The oldest fossilized cells resemble prokaryotes
Which of the following pieces of evidence best supports the hypothesis that birds and crocodilians are more closely related to each other than they are to other organisms
The skulls of birds and crocodilians have an opening that is absent in the skulls of other reptiles
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 and extremely virulent, affects both populations at the same time. Which of the following is the best prediction of how the new disease will affect the two populations
The small population will be more affected than will the large population, because the smaller population has less genetic variation that the larger population has
Which of the following is the most likely explanation for a high rate of crossing-over between two genes
The two genes are far apart on the same chromosome
Prairie dogs are small mammals that live in large colonies in burrows in the ground. Prairie dogs that are near their own relatives when a predator approaches are much more likely to issue a warning bark than those that are near unrelated prairie dogs. The prairie dogs that hear a warning bark are more likely to hide in their burrows than to remain above ground. However, the prairie dog that gives a warning bark is putting itself at increased risk of being identified and killed by the predator. Which of the following presents the most likely evolutionary explanation for the behaviors described
The warning bark changes the behavior of the related prairie dogs nearby, allowing the prairie dog's family to have increased survival and reproductive success
What is the process in which RNA is produced by using a DNA template
Transcription
What is the process in which a protein is assembled at a ribosome
Translation
IN peas the trait for tall plant is dominant (T) and the trait for short plants is recessive (t). The triat for tellow seed color is dominant (Y) and the trait for green seed color is recessive (y). A cross between two plants results in 296 tall yellow plants and 104 tall green plants. Which of the following are the most likely to be the genotypes of the parents
TtYy x TTYy
A genetic counselor is consulted by a young man who is worried about developing Huntington's disease, an inherited disorder caused by a dominant allele of a singe gene. The young man explains that his cousin was recently diagnosed with Huntington's disease, and the news has caused him to consider his own risk of developing the disorder. Which of the following questions will best help the genetic counselor to evaluate the risk of the young man developing Huntington's disease and transmitting it to his children
Were your parents or grandparents ever diagnosed with Huntington's disease
In an experiment, DNA from the linear form of the bacteriophage Lambda was cut into fragments using the restriction enzyme Hind III cuts the Lambda DNA between the adenine nucleotides on the complimentary strands in a specific sequence, as indicated in the diagram, producing eight different size fragments. These fragments are then separated with an electrical current based on size after the DNA fragments are placed in a porous gel, a process called gel electrophoresis. Select an observation that best describes a correct aspect of the two processes of restriction digest and gel electrophoresis
When separated on a gel, the pattern of DNA bands will be characteristic of those cut with Hind III; different restriction enzymes will not produce these same fragments
Alternating patterns of gene expression in prokaryotes would most likely serve the organism's survival in which of the following ways
allowing the organism to adjust to changes in environmental conditions
Which of the following accounts for someone who has had a herpesvirus-medicated cold sore or genital sore getting flare-ups for the rest of life
copies of the herpesvirus genome permanently maintained in host nuclei
Assume that you are trying to insert a gene into a plasmid. Someone gives you a preparation of genomic DNA that has been cut with restriction enzyme X. The gene you wish to insert has sites on both ends for cutting by restriction enzyme Y. You have a plasmid with a single site for Y, but not for X. Your strategy should be to
cut the DNA again with restriction enzyme Y and insert these fragments into the plasmid cut with the same enzyme
Coat color in mice is determined by genes at two loci. When black mice from a particular population mate, they produce offspring in the following ratios: 9 black, 3 brown, 4 white. These results suggest that white coat color is expressed as a result of
epistasis
Which of the following separates molecules by movement deu to size and electrical charge
gel electrophoresis
In a small group of people living in a remote area, there is a high incidence of "blue-skin," a condition that results from a variation in the structure of hemoglobin. All of the "blue-skinned" residents can trace their ancestry to one couple, who were among the original settlers of this region. The unusually high frequency of "blue skin" in the area is an example of
genetic drift
Which of the following can be effective in preventing viral infection in humans
getting vaccinated
After telophase I of meiosis, the chromosomal makeup of each daughter cell is
haploid, and the chromosomes are each composed of two chromatids.
Muscle cells and nerve cells in one species of animal owe their differences in structure to
having different genes expressed
What is the role of DNA ligase in the elongation of the lagging strand during DNA replication
join Okazaki fragments together
What is the enzyme used during replication to attach Okazaki fragments to each other
ligase
Some varieties of Neisseria gonorrhoeae are now resistant to penicillin. The varieties of bacteria most probably developed as a result of
natural selection
The F1 offspring of Mendel's classic pea cross always looked like one of the two parental varieties because
one phenotype was completely dominant over the other
RFLP analysis can be used to distinguish between alleles based on differences in which of the following
restriction enzyme recognition sites between the alleles
What is the name given to viruses that have single-stranded RNA that acts as a template for DNA synthesis
retroviruses
The appearance of a fertile, polyploid individual within a population of diploid organisms is a possible source of a new species. If this individual is capable of reproducing to form a new population, scientists would consider this to be an example of
sympatric speciation
From the following list, which is the first even in translation in eukaryotes
the small subunit of the ribosome recognizes and attaches to the 5' cap of mRNA
The tryptophan operon is a repressible operon that is
turned off whenever tryptophan is added to the growth medium
How can a gene that contains introns be made shorter ( but remain functional) for genetic engineering purposes
using reverse transcriptase to reconstruct the gene from its RNA
