CHAPTER 11 Quiz
Ch 12 quiz
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Ch 13 Quiz
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In certain plants, the tall trait is dominant to the short trait. If a heterozygous plant is crossed with a homozygous tall plant, what is the probability that the offspring will be short?
0
The figure above shows a pedigree chart for a family, some of whose members exhibit the dominant trait, W. Affected individuals are indicated by a dark square or circle. What is the probability that individual III-1 is W w?
1
In a particular plant, leaf color is controlled by gene locus D. Plants with at least one D allele have dark green leaves, and plants with the homozygous recessive dd genotype have light green leaves. A true-breeding dark-leaved plant is crossed with a light-leaved one, and the F1 offspring is allowed to self-pollinate. The predicted outcome of the F 2 is diagrammed in the Punnett square shown in the figure above, where 1, 2, 3, and 4 represent the genotypes corresponding to each box within the square. Which of the plants will be true-breeding?
1 and 4 only
One map unit is equivalent to which of the following values?
1% frequency of recombination between two genes
In a particular plant, leaf color is controlled by gene locus D. Plants with at least one D allele have dark green leaves, and plants with the homozygous recessive dd genotype have light green leaves. A true-breeding dark-leaved plant is crossed with a light-leaved one, and the F 1 offspring is allowed to self-pollinate. The predicted outcome of the F 2 is diagrammed in the Punnett square shown in the figure above, where 1, 2, 3, and 4 represent the genotypes corresponding to each box within the square. Which of the boxes correspond(s) to plants with a heterozygous genotype?
1,2,3 wrong
In the cross AaBbCc × AaBbCc, what is the probability of producing the genotype AABBCC?
1/64
A man who is a dwarf due to achondroplasia and has normal vision marries a color-blind woman of normal height. The man's father was 6 feet tall, and both the woman's parents were of average height. Achondroplasia is autosomal dominant, and red-green color blindness is X-linked recessive. They have a daughter who is a dwarf with normal color vision. What is the probability that she is heterozygous for both genes?
100%
Cinnabar eyes is a sex-linked recessive characteristic in fruit flies in which the eyes of the individual are lighter in color than the normal wild-type red color. If a female having cinnabar eyes is crossed with a wild-type male, what percentage of the F 1 males will have cinnabar eyes?
100%
Achondroplasia, a form of dwarfism in humans, is caused by a dominant allele. What is the probability of a heterozygous dwarf man and a normal, homozygous woman having a child who is a heterozygous dwarf?
25% wrong
Given the following cross between parents of the genotypes AABBCc × AabbCc, assume complete dominance for each trait and independent assortment. What proportion of the progeny will be expected to phenotypically resemble the first parent?
3/4
When crossing an organism that is homozygous recessive for a single trait with one that is heterozygous for the same trait, what is the chance of producing an offspring with the homozygous recessive phenotype?
50%
Radish flowers may be red, purple, or white. A cross between a red-flowered plant and a white-flowered plant yields all-purple offspring. The part of the radish we eat may be oval or long, with long being the dominant trait. True-breeding red-flowered long radishes are crossed with true-breeding white-flowered radishes. All of the F 1 offspring are purple-flowered and long radishes. In the F 2 generation of this cross, which of the following phenotypic ratios would be expected?
6:3:3:2:1:1
How many unique gametes could be produced through independent assortment by an individual with the genotype AaBbCCDdEE?
8
In an analysis of the nucleotide composition of DNA, which of the following will be found in a given DNA molecule?
A + C = G + T
Which of the following statements correctly describes a dihybrid cross?
A dihybrid cross involves organisms that are heterozygous for two characters.
Which of the following statements correctly describes a monohybrid cross?
A monohybrid cross involves organisms that are heterozygous for one character
Which of the following statements best describes the SRY gene?
It is a gene region present on the Y chromosome that triggers male development.
A couple has a child with Down syndrome. The mother is 39 years old at the time of delivery. Which of the following is the most probable cause of the child's condition?
Nondisjunction occurred in one member of the couple during gamete production.
QUESTION 20 All seven of the pea plant traits studied by Mendel obeyed the principle of independent assortment. Which of the following statements correctly describes what this indicates about those traits?
All of the genes controlling the traits behaved as if they were located on different chromosomes.
For a science fair project, two students decided to repeat the Hershey and Chase experiment, with modifications. They decided to label the nitrogen of the DNA rather than the phosphate. They reasoned that each nucleotide has only one phosphate and two to five nitrogens. Thus, labeling the nitrogens would provide a stronger radioactive signal than labeling the phosphates. Why won't this experiment work?
Amino acids (and thus proteins) also have nitrogen atoms; thus, the radioactivity would not distinguish between DNA and proteins.
A woman who has blood type A positive has a daughter who is type O positive and a son who is type B negative. Rh positive is a trait that shows simple dominance over Rh negative and is designated by the alleles R and r, respectively. Which of the following is a possible phenotype for the father?
B positive
Which of the following calculations described in the following statements require that you use the addition rule?
Calculate the probability of a child having only sickle-cell anemia or cystic fibrosis if each parent is each heterozygous for both traits
In trying to determine whether DNA or protein was the genetic material, Hershey and Chase made use of which of the following facts about these two types of molecules?
DNA contains phosphorus, whereas protein does not.
A student isolates, purifies, and combines in a test tube a variety of molecules needed for DNA replication. After adding some DNA to the mixture, replication occurs, but each DNA molecule consists of a normal strand paired with numerous segments of DNA a few hundred nucleotides long. What has the student probably left out of the mixture?
DNA ligase
During DNA replication in E. coli, which of the following enzymes removes the RNA nucleotides from the primer and adds equivalent DNA nucleotides to the 3' end of Okazaki fragments?
DNA polymerase I
Which enzyme in E. coli catalyzes the elongation of a DNA strand in the 5' → 3' direction?
DNA polymerase III
What is the basis for the difference in how the leading and lagging strands of DNA molecules are synthesized?
DNA polymerase can join new nucleotides only to the 3' end of a preexisting strand
What evidence did Alfred Sturtevant use to support his conclusion that Drosophila have four pairs of chromosomes?
Drosophila genes cluster into four distinct groups of linked genes.
Which of the following events causes recombination between linked genes to occur?
Crossovers between the genes results in chromosomal exchange.
Labrador retrievers are black, brown, or yellow. In a cross of a black female with a brown male, results can be all black puppies, 1/2 black to 1/2 brown puppies, or 3/4 black to 1/4 yellow puppies. These results indicate which of the following about the inheritance pattern of fur color in Labrador retrievers?
Epistasis is involved.
What is the most logical sequence of steps for splicing foreign DNA into a plasmid and inserting the plasmid into a bacterium?
Extract plasmid DNA from bacterial cells. Cut the plasmid DNA using restriction enzymes. Hydrogen-bond the plasmid DNA to nonplasmid DNA fragments. Use ligase to seal plasmid DNA to nonplasmid DNA. Transform bacteria with a recombinant DNA molecule.
Which of the following statements correctly describes an example of epistasis?
In rabbits and many other mammals, one genotype (ee) prevents any fur color from developing.
Three genes ( A, B, and C) at three loci are being mapped in a particular species. Each gene has two alleles, each of which results in a dominant or recessive phenotype. The dominant allele of gene A is inherited with the dominant allele of gene B or C about 50% of the time. However, the dominant alleles of genes B and C are inherited together 14.4% of the time. Which of the following statements describes what is happening regarding the inheritance of these genes?
Gene A is assorting independently of genes B and C, which are linked.
A sexually reproducing animal has two unlinked genes, one for head shape ( H) and one for tail length ( T). Its genotype is HhTt. Which of the following genotypes is possible in a gamete from this organism?
HT
The figure above represents a pedigree for a family in which dark-shaded symbols represent individuals with one of the two major types of colon cancer. Numbers under the symbols are the individuals' age at the time of diagnosis. A slash through the symbol indicates that the individual is deceased. In each generation of this family after generation I, the age at diagnosis is significantly lower than would be found in nonfamilial (sporadic) cases of this cancer (~63 years). What is the most likely reason?
Hereditary (or familial) cases of this cancer typically occur at earlier ages than do nonfamilial forms.
Which of the following statements correctly describes one difference between heterochromatin and euchromatin?
Heterochromatin is highly condensed, whereas euchromatin is less compact.
Why do histones bind tightly to DNA?
Histones are positively charged, and DNA is negatively charged.
The figure above represents a pedigree for a family in which dark-shaded symbols represent individuals with one of the two major types of colon cancer. Numbers under the symbols are the individuals' age at the time of diagnosis. A slash through the symbol indicates that the individual is deceased. The affected woman in generation IV is thinking about her future and asks her oncologist (cancer specialist) whether she can know if any or all of her children will have a high risk of the same cancer. The doctor would be expected to advise which of the following: (I) genetic counseling; (II) prenatal diagnosis when/if she becomes pregnant; (III) testing to see whether she has the allele; (IV) testing to see whether her future spouse or partner has the allele?
I: genetic counseling only
QUESTION 7 A woman who has blood type A positive has a daughter who is type O positive and a son who is type B negative. Rh positive is a trait that shows simple dominance over Rh negative and is designated by the alleles R and r, respectively. Which of the following is a possible partial genotype for the mother?
IAi
A woman who has blood type A positive has a daughter who is type O positive and a son who is type B negative. Rh positive is a trait that shows simple dominance over Rh negative and is designated by the alleles R and r, respectively. Which of the following is a possible genotype for the son?
IBi
Phenylketonuria (PKU) is a disease in humans that results from the abnormal metabolism of the amino acid phenylalanine. If untreated, it can lead to severe brain damage in infants. Two normal parents have a child who has PKU. What can you determine about the inheritance of the PKU allele from this information?
It is dominant. wrong
What is the role of DNA ligase in the elongation of the lagging strand during DNA replication?
It joins Okazaki fragments together.
How does the recombination of linked genes contribute to natural selection?
It maintains genetic variability in a species.
Which of the following statements describes the chromosome theory of inheritance as expressed in the early twentieth century?
Mendelian genes are at specific loci on the chromosome and in turn segregate during meiosis.
In his transformation experiments, which of the following results did Griffith observe?
Mixing a heat-killed pathogenic strain of bacteria with a living nonpathogenic strain can convert some of the living cells into the pathogenic form.
Which of the following statements correctly describes aneuploid conditions?
Monosomy X is the only known viable human monosomy.
Why did the F 1 offspring of Mendel's classic pea cross always look like one of the two parental varieties?
One allele was dominant.
If cell X enters meiosis, and nondisjunction of one chromosome occurs in one of its daughter cells during meiosis II, what will be the result at the completion of meiosis?
One-fourth of the gametes descended from cell X will be n + 1, 1/4 will be n - 1, and 1/2 will be n.
What is the reason that closely linked genes are typically inherited together?
The likelihood of a crossover event between these two genes is low.
Which of the following statements correctly describes one of Chargaff's rules regarding DNA?
The percentages of adenine and thymine are roughly equal, as are the percentages of guanine and cytosine in the DNA of a given species.
Which of the following statements describes one difference between DNA replication in prokaryotes and DNA replication in eukaryotes?
Prokaryotic chromosomes have a single origin of replication, whereas eukaryotic chromosomes have many
After mixing a heat-killed, phosphorescent (light-emitting) strain of bacteria with a living, nonphosphorescent strain, you discover that some of the living cells are now phosphorescent. Which observation(s) would provide the best evidence that the ability to phosphoresce is a heritable trait?
The phosphorescence in the living strain is especially bright. - incorrect WRONG
What is meant by the description "antiparallel" regarding the two strands of nucleic acids that make up DNA?
The 5' to 3' direction of one strand runs counter to the 5' to 3' direction of the other strand.
Which of the following statements correctly describes gene linkage?
The closer two genes are on a chromosome, the lower the probability that a crossover will occur between them
Which of the following statements regarding Down syndrome is correct?
The frequency increases with the age of the mother.
Which of the following statements correctly describes one difference between the law of independent assortment and the law of segregation?
The law of independent assortment explains the segregation of two or more genes relative to one another.
Two autosomal genes have a recombination frequency of 16%. Which of the following conclusions can be drawn regarding these genes?
The two genes are closely linked on the same chromosome.
A group of six 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 a particular gene of interest.Analysis of the data obtained shows that two students each have two fragments, two students each have three fragments, and two students each have one only. What does this demonstrate?
The two students who have two fragments have one restriction site in this region.
What was the most significant conclusion that Gregor Mendel drew from his experiments with pea plants?
Traits are inherited in discrete units and are not the results of the "blending" of traits.
What was Mendel's explanation for his observation that traits that had disappeared in the F 1 generation reappeared in the F 2 generation of the pea plants he used in his experiments?
Traits can be dominant or recessive, and the recessive traits were "hidden" by the dominant ones in the F1.
Duchenne muscular dystrophy is a serious condition caused by a recessive allele of a gene on the human X chromosome. The patients have muscles that weaken over time because they have absent or decreased dystrophin, a muscle protein. They rarely live past their 20s. How likely is it for a woman to have this condition?
Very rarely: it is rare that an affected male would mate with a carrier female.
A man who is a dwarf due to achondroplasia and has normal vision marries a color-blind woman of normal height. The man's father was 6 feet tall, and both the woman's parents were of average height. Achondroplasia is autosomal dominant, and red-green color blindness is X-linked recessive.How many of the couple's daughters might be expected to be color-blind dwarfs?
Wrong answer - half
Normally, only female cats have the tortoiseshell phenotype because
a male inherits only one allele of the X-linked gene controlling hair color.
Gene S controls the sharpness of spines in a type of cactus. Cactuses with the dominant allele, S, have sharp spines, whereas homozygous recessive ss cactuses have dull spines. At the same time, a second gene, N, determines whether or not cactuses have spines. Homozygous recessive nn cactuses have no spines at all. A cross between a true-breeding sharp-spined cactus and a spineless cactus homozygous for dull spines would produce
all sharp-spined progeny.
How does a bacterial cell protect its own DNA from restriction enzymes?
by adding methyl groups to adenines and cytosines
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.
The elongation of the leading strand during DNA synthesis
depends on the action of DNA polymerase
Which of the following statements describes the major reason that an individual with the genotype AaBbCCDdEE can make many kinds of gametes?
different possible assortment of chromosomes into gametes
Which of the following sets of materials is required by both eukaryotes and prokaryotes for DNA replication?
double-stranded DNA, four kinds of DNA nucleotides, primers, origins of replication
Gene S controls the sharpness of spines in a type of cactus. Cactuses with the dominant allele, S, have sharp spines, whereas homozygous recessive ss cactuses have dull spines. At the same time, a second gene, N, determines whether or not cactuses have spines. Homozygous recessive nn cactuses have no spines at all. The relationship between genes S and N is an example of
epistasis.
Which of the following results might be caused by a chromosomal translocation?
exchange of nonhomologous chromosome fragments
A woman is found to have 47 chromosomes, including three X chromosomes. Which of the following describes her expected phenotype?
healthy female of slightly above-average height
A eukaryotic gene has "sticky ends" produced by the restriction endonuclease EcoRI. The gene is added to a mixture containing EcoRI and a bacterial plasmid that carries two genes conferring resistance to the antibiotics ampicillin and tetracycline. The plasmid has one recognition site for EcoRI located in the tetracycline resistance gene. This mixture is incubated for several hours, exposed to DNA ligase, and then added to bacteria growing in nutrient broth. The bacteria are allowed to grow overnight and are streaked on a plate using a technique that produces isolated colonies that are clones of the original. Samples of these colonies are then grown in four different media: nutrient broth plus ampicillin, nutrient broth plus tetracycline, nutrient broth plus ampicillin and tetracycline, and nutrient broth without antibiotics.Bacteria that contain the plasmid, but not the eukaryotic gene, would grow in which of the following conditions?
in all four types of broth
You briefly expose bacteria undergoing DNA replication to radioactively labeled nucleotides. When you centrifuge the DNA isolated from the bacteria, the DNA separates into two classes. One class of labeled DNA includes very large molecules (thousands or even millions of nucleotides long), and the other includes short stretches of DNA (several hundred to a few thousand nucleotides in length). These two classes of DNA probably represent
leading strands and Okazaki fragments
Males are more often affected by sex-linked traits than females because
males are hemizygous for the X chromosome.
Which of the following mechanisms removes nucleotides that are paired incorrectly during DNA replication?
mismatch repair
Characters in humans such as a person's red and white blood cell counts vary quite a bit depending on such factors as altitude and physical activity. Traits like this are referred to as
multifactorial.
What is the source of the extra chromosome 21 in an individual with Down syndrome?
nondisjunction in either parent
The spontaneous loss of amino groups from adenine in DNA results in hypoxanthine, an uncommon base, opposite thymine. What combination of proteins could repair such damage?
nuclease, DNA polymerase, DNA ligase
Which of the following lists of structures correctly represents the order of increasingly higher levels of organization of chromatin?
nucleosome, 30-nm chromatin fiber, looped domain
In humans, wavy hair occurs in heterozygotes (H SH C) offspring of people with straight hair (H SH S) and curly hair (H CH C). Which of the following crosses would produce offspring with the ratio of 1 straight:2 wavy:1 curly?
wavy x wavy
Cystic fibrosis affects the lungs, the pancreas, the digestive system, and other organs, resulting in symptoms ranging from breathing difficulties to recurrent infections. Which of the following terms best describes this expression of phenotypes?
pleiotropy
Skin color in humans has a wide variety of phenotypes. The expression of this trait is caused by more than two genes. What type of inheritance pattern is responsible for this expression?
polygenic inheritance
Radish flowers may be red, purple, or white. A cross between a red-flowered plant and a white-flowered plant yields all-purple offspring. The part of the radish we eat may be oval or long, with long being the dominant trait. If true-breeding red-flowered long radishes are crossed with true-breeding white-flowered oval radishes, the F 1 will be expected to be which of the following?
purple-flowered and long
Which of the following molecule(s) help(s) to hold the DNA strands apart while they are being replicated?
single-strand binding proteins
In his work with pneumonia-causing bacteria and mice, Griffith found that
some substance from pathogenic cells was transferred to nonpathogenic cells, making them pathogenic.
Two plants are crossed, resulting in offspring with a 3:1 ratio for a particular trait. What does this suggest about the trait?
that the parents were both heterozygous for a single trait
A eukaryotic gene has "sticky ends" produced by the restriction endonuclease EcoRI. The gene is added to a mixture containing EcoRI and a bacterial plasmid that carries two genes conferring resistance to the antibiotics ampicillin and tetracycline. The plasmid has one recognition site for EcoRI located in the tetracycline resistance gene. This mixture is incubated for several hours, exposed to DNA ligase, and then added to bacteria growing in nutrient broth. The bacteria are allowed to grow overnight and are streaked on a plate using a technique that produces isolated colonies that are clones of the original. Samples of these colonies are then grown in four different media: nutrient broth plus ampicillin, nutrient broth plus tetracycline, nutrient broth plus ampicillin and tetracycline, and nutrient broth without antibiotics.Bacteria that do not take up any plasmids would grow on which media?
the nutrient broth only
QUESTION 11 The addition rule of probability can be defined as
the probability that either one of two mutually exclusive events will occur.
What is the function of DNA polymerase III in replication in E. coli?
to add nucleotides to the 3' end of a growing DNA strand
Why did Mendel continue some of his experiments to the F 2 generation?
to observe whether or not the dominant trait would reappear wrong
In cats, black fur color is caused by an X-linked allele; the other allele at this locus causes orange color. The heterozygote is tortoiseshell. What kinds of offspring would you expect from the cross of a black female and an orange male?
tortoiseshell females; black males
One possible result of chromosomal breakage is for a fragment to join a nonhomologous chromosome. What is this alteration called?
translocation
Which of the following sequences in double-stranded DNA is most likely to be recognized as a cutting site for a restriction enzyme?
wrong - AAAA TTTT
In a linear eukaryotic chromatin sample, which of the following strands is looped into nucleosomes?
wrong - the 30nm chromatin fiber
The figure above shows a pedigree chart for a family, some of whose members exhibit the dominant trait, W. Affected individuals are indicated by a dark square or circle. What is the genotype of individual II-5?
ww
Labrador retrievers have black, brown, or yellow fur. Fur color is controlled by two genes, one of which exhibits epistasis. Black ( B) is dominant over brown ( b) in one gene, and ( E) is dominant over ( e) in the other gene. The (E) gene is epistatic to the (B) gene. In a cross of a black female with a brown male, results can be all black puppies, 1/2 black to 1/2 brown puppies, or 3/4 black to 1/4 yellow puppies. In one cross of black × black, the results were as follows:9/16 black, 4/16 yellow, 3/16 brown. The genotype eebb must result in which of the following?
yellow
Tallness ( T) in snapdragon plants is dominant to dwarfness ( t), and red (C R) flower color is not dominant to white (C W). The heterozygous condition results in pink (C RC W) flower color. A dwarf red snapdragon is crossed with a plant homozygous for tallness and white flowers. What are the genotype and phenotype of the F 1 individuals?
—TtCRCW, tall and pink