Test 4

D) translocation

. One possible result of chromosomal breakage is for a fragment to join a nonhomologous chromosome. What is this alteration called? A) deletion B) transversion C) inversion D) translocation E) duplication

D) 1/2

1. 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 crosses BbTt × BBtt will be expected to have black fur and long tails? A) 1/16 B) 3/16 C) 3/8 D) 1/2 E) 9/16

C) UUU.

A particular triplet of bases in the coding sequence of DNA is AAA. The anticodon on the tRNA that binds the mRNA codon is A) TTT. B) UUA. C) UUU. D) AAA.

A) 3'-UCA-5'.

A particular triplet of bases in the template strand of DNA is 5'-AGT-3'. The corresponding codon for the mRNA transcribed is A) 3'-UCA-5'. B) 3'-UGA-5'. C) 5'-TCA-3'. D) 3'-ACU-5'. E) either UCA or TCA, depending on wobble in the first base

B) DNA ligase

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? A) DNA polymerase B) DNA ligase C) Okazaki fragments D) primase

D) I B i

A woman who has blood type A positive has a daughter who is type O positive and a son who is type B negative. Which of the following is a possible genotype for the son? A) I B I B B) I AI B C) ii D) I B i E) I AI A

E) A and G

Between which two genes would you expect the highest frequency of recombination? A) A and W B) W and E C) E and G D) A and E E) A and G

A) helicase

During DNA replication, which of the following enzymes separates the DNA strands during replication? A) helicase B) DNA polymerase III C) ligase D) DNA polymerase I E) primase

D) one low-density and one intermediate-density band

E. coli cells grown on 15N medium are transferred to 14N medium and allowed to grow for two more generations (two rounds of DNA replication). DNA extracted from these cells is centrifuged. What density distribution of DNA would you expect in this experiment? A) one high-density and one low-density band B) one intermediate-density band C) one high-density and one intermediate-density band D) one low-density and one intermediate-density band

E) 3'-AAA-GAA-TAA-CAA-5'.

Examine the table of codons in Figure 14.2. A possible sequence of nucleotides in the template strand of DNA that would code for the polypeptide sequence phe-leu-ile-val would be A) 5'-TTG-CTA-CAG-TAG-3'. B) 3'-AAC-GAC-GUC-AUA-5'. C) 5'-AUG-CTG-CAG-TAT-3'. D) 3'-AAA-AAT-ATA-ACA-5'. E) 3'-AAA-GAA-TAA-CAA-5'.

D) met-ser-ser-leu-ser-leu

Examine the table of codons in Figure 14.2. What amino acid sequence will be produced based on the following mRNA codon sequence? 5'-AUG-UCU-UCG-UUA-UCC-UUG-3' A) met-arg-glu-arg-glu-arg B) met-glu-arg-arg-glu-leu C) met-ser-leu-ser-leu-ser D) met-ser-ser-leu-ser-leu E) met-leu-phe-arg-glu-glu

B) none

How many of the couple's daughters might be expected to be color-blind dwarfs? A) all B) none C) half D) one out of four E) three out of four

D) Erwin Chargaff

In DNA from any species, the amount of adenine equals the amount of thymine, and the amount of guanine equals the amount of cytosine. Which of the following investigators was (were) responsible for this discovery? A) Frederick Griffith B) Alfred Hershey and Martha Chase C) Oswald Avery D) Erwin Chargaff E) Matthew Meselson and Franklin Stahl

C) histones

In a nucleosome, the DNA is wrapped around A) polymerase molecules. B) ribosomes. C) histones. D) a thymine dimer.

B) A + G = C + T

In analyzing the number of different bases in a DNA sample, which result would be consistent with the base-pairing rules? A) A = G B) A + G = C + T C) A + T = G + C D) A = C 28. The elongation

D) tortoiseshell femals; black males

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 (calico). What kinds of offspring would you expect from the cross of a black female and an orange male? A) tortoiseshell females; tortoiseshell males B) black females; orange males C) orange females; orange males D) tortoiseshell females; black males E) orange females; black males

B) roan x roan

In cattle, roan coat color (mixed red and white hairs) occurs in the heterozygous (Rr) offspring of red (RR) white (rr) homozygotes. Which of the following crosses would produce offspring in the ratio of 1 red: 2 roan: 1 white? A) red × white B) roan × roan C) white × roan D) red × roan

E) 0

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? A) 1 B) 1/2 C) 1/4 D) 1/6 E) 0

C) RNA polymerase II

In eukaryotes there are several different types of RNA polymerase. Which type is involved in transcription of mRNA known as pre-mRNA? A) ligase B) RNA polymerase I C) RNA polymerase II D) RNA polymerase III

B) several transcription factors have bound to the promoter

In eukaryotic cells, transcription cannot begin until A) the two DNA strands have completely separated and exposed the promoter. B) several transcription factors have bound to the promoter. C) the 5' caps are removed from the mRNA. D) the DNA introns are removed from the template.

C) some substance from pathogenic cells was transferred to nonpathogenic cells, making them pathogenic

In his work with pneumonia-causing bacteria and mice, Griffith found that A) the protein coat from pathogenic cells was able to transform nonpathogenic cells. B) heat-killed pathogenic cells caused pneumonia. C) some substance from pathogenic cells was transferred to nonpathogenic cells, making them pathogenic. D) the polysaccharide coat of bacteria caused pneumonia.

C) It is pleiotropic

Marfan syndrome in humans is caused by an abnormality of the connective tissue protein fibrillin resulting from a single gene. Patients develop many different phentotypic traits. Patients are usually very tall and thin, with long spindly fingers, curvature of the spine, sometimes weakened arterial walls, and sometimes eye problems, such as lens dislocation. Which of the following would you conclude about Marfan syndrome from this information? Very similar scenario to sickle cell anemia discussed in lecture. A) It is recessive. B) It is dominant. C) It is pleiotropic. D) It is epistatic.

E) XNXn and XNY

Red-green color blindness is a sex-linked recessive trait in humans. Two people with normal color vision have a colorblind son. What are the genotypes of the parents? A) XNXn and XnY B) XnXn and XNY C) XNXN and XnY D) XNXN and XNY E) XNXn and XNY

A) complementary to the corresponding mRNA codon

The anticodon of a particular tRNA molecule is A) complementary to the corresponding mRNA codon. B) complementary to the corresponding triplet in rRNA. C) the part of tRNA that bonds to a specific amino acid. D) catalytic, making the tRNA a ribozyme.

D) depends on the action of DNA polymerase

The elongation of the leading strand during DNA synthesis A) progresses away from the replication fork. B) occurs in the 3' → 5' direction. C) produces Okazaki fragments. D) depends on the action of DNA polymerase.

A) nuclease, DNA polymerase, DNA ligase

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? A) nuclease, DNA polymerase, DNA ligase B) topoisomerase, primase, DNA polymerase C) topoisomerase, helicase, single-strand binding protein D) DNA ligase, replication fork proteins, adenylyl cyclase

E) 100%

They have a daughter who is a dwarf with normal color vision. What is the probability that she is heterozygous for both genes? A) 0% B) 25% C) 50% D) 75% E) 100%

A) The two genes are likely to be located on different chromosomes

What does a frequency of recombination of greater than 50% indicate? A) The two genes are likely to be located on different chromosomes. B) All of the offspring have combinations of traits that match one of the two parents. C) The genes are located on sex chromosomes. D) The two genes are likely to be located on the same chromosomes.

A) activation of the XIST gene on the X chromosome that will become the Barr body

What event causes all female mammals to have one active X chromosome per cell instead of two? A) activation of the XIST gene on the X chromosome that will become the Barr body B) activation of the BARR gene on one X chromosome, which then becomes inactive C) crossing over between the HeTis gene on one X chromosome and a related gene on an autosome D) inactivation of the SRY gene on the X chromosome derived from the male parent

B) an RNA with enzymatic activity

What is a ribozyme? A) an enzyme that uses RNA as a substrate B) an RNA with enzymatic activity C) an enzyme that catalyzes the association between the large and small ribosomal subunits D) an enzyme that synthesizes RNA as part of the transcription process E) an enzyme that synthesizes RNA primers during DNA replication

A) DNA polymerase can join new nucleotides only to the 3' end of the preexisting strand

What is the basis for the difference in how the leading and lagging strands of DNA molecules are synthesized? A) DNA polymerase can join new nucleotides only to the 3' end of a preexisting strand. B) Helicases and single-strand binding proteins work at the 5' end. C) The origins of replication occur only at the 5' end. D) DNA ligase works only in the 3' → 5' direction.

A) relieving strain in the DNA ahead of the replication fork

What is the function of topoisomerase? A) relieving strain in the DNA ahead of the replication fork B) elongating new DNA at a replication fork by adding nucleotides to the existing chain C) adding methyl groups to bases of DNA D) unwinding of the double helix E) stabilizing single-stranded DNA at the replication fork

C) ww

What is the genotype of individual II-5? A) WW B) Ww C) ww D) WW or ww E) ww or Ww

C) 50%

What is the likelihood that the offspring of IV-3 and IV-4 will have the trait? Figure 11.2 A) 0% B) 25% C) 50% D) 75% E) 100%

E) 1

What is the probability that individual III-1 is Ww? A) 3/4 B) 1/4 C) 2/4 D) 2/3 E) 1

B) half

What proportion of their sons would be color-blind and of normal height? A) none B) half C) one out of four D) three out of four

B) The gene involved is on the X chromosome

When Thomas Hunt Morgan crossed his red-eyed F1 generation flies to each other, the F2 generation included both red- and white-eyed flies. Remarkably, all the white-eyed flies were male. What was the explanation for this result? A) The gene involved is on the Y chromosome. B) The gene involved is on the X chromosome. C) The gene involved is on an autosome, but only in males. D) Eye color in flies is a multifactorial trait.

B) DNA

Which component is not directly involved in translation? A) GTP B) DNA C) tRNA D) ribosomes

C) DNA polymerase III

Which enzyme catalyzes the elongation of a DNA strand in the 5' → 3' direction? A) primase B) DNA ligase C) DNA polymerase III D) topoisomerase E) helicase

D) 2 and 3

Which of the boxes correspond(s) to plants with a heterozygous genotype? A) 1 only B) 1 and 2 Figure 11.1 C) 1, 2, and 3 D) 2 and 3 E) 2, 3, and 4

E) 1, 2, and 3

Which of the boxes marked 1-4 correspond(s) to plants with dark leaves? A) 1 only B) 1 and 2 C) 2 and 3 D) 4 only E) 1, 2, and 3

A) a base-pair deletion

Which of the following DNA mutations is likely to have the most negative effect on the protein it specifies? A) a base-pair deletion B) a codon substitution C) a substitution in the last base of a codon D) a codon deletion

D) single-strand binding proteins

Which of the following help(s) to hold the DNA strands apart while they are being replicated? A) primase B) ligase C) DNA polymerase D) single-strand binding proteins E) nuclease

D) It helps protect the mRNA from degradation by hydrolytic enzymes.

Which of the following is a function of a poly-A tail in mRNA? A) It adds the modified guanine to the 3' end of the mRNA. B) It indicates the site of translational termination. C) It is a sequence that codes for the binding of RNA polymerase to the DNA. D) It helps protect the mRNA from degradation by hydrolytic enzymes.

A) exons are cut out before mRNA leaves the nucleus

Which of the following is not true of RNA processing? A) Exons are cut out before mRNA leaves the nucleus. B) Nucleotides may be added at both ends of the RNA. C) Ribozymes may function in RNA splicing. D) RNA splicing can be catalyzed by spliceosomes.

C) it extends from one end of a tRNA molecule

Which of the following is not true of a codon? A) It may code for the same amino acid as another codon. B) It never codes for more than one amino acid. C) It extends from one end of a tRNA molecule. D) It is the basic unit of the genetic code.

D) a single nucleotide insertion downstream of, and close to, the start of the coding sequence

Which of the following mutations would be most likely to have a harmful effect on an organism? A) a deletion of three nucleotides near the middle of a gene B) a single nucleotide deletion in the middle of an intron C) a single nucleotide deletion near the end of the coding sequence D) a single nucleotide insertion downstream of, and close to, the start of the coding sequence

C) It is a gene region present on the Y chromosome that triggers male development

Which of the following statements best describes the SRY gene? A) It is a gene present on the X chromosome that triggers female development. B) It is an autosomal gene that is required for the expression of genes on the Y chromosome. C) It is a gene region present on the Y chromosome that triggers male development. D) It is an autosomal gene that is required for the expression of genes on the X chromosome.

E) skin pigmentation in humans

Which of the following traits is an example of polygenic inheritance? A) pink flowers in snapdragons B) the ABO blood group in humans C) Huntington's disease in humans D) white and purple flower color in peas E) skin pigmentation in humans

A) 1 and 4 only

Which of the plants will be true-breeding? A) 1 and 4 only B) 2 and 3 only C) 1, 2, 3, and 4 D) 1 only E) 1 and 2 only