BIO 101 - Chapter 13 - The Molecular Basis of Inheritance

D) Amino acids (and thus proteins) also have nitrogen atoms; thus, the radioactivity would not distinguish between DNA and proteins.

1) 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 signal than labeling the phosphates. Why won't this experiment work? A) There is no radioactive isotope of nitrogen. B) Avery et al. have already concluded that this experiment showed inconclusive results. C) Although there are more nitrogens in a nucleotide, labeled phosphates actually have 16 extra neutrons; therefore, they are more radioactive. D) Amino acids (and thus proteins) also have nitrogen atoms; thus, the radioactivity would not distinguish between DNA and proteins.

B) Mixing a heat-killed pathogenic strain of bacteria with a living nonpathogenic strain can convert some of the living cells into the pathogenic form.

1) In his transformation experiments, what did Griffith observe? A) Mutant mice were resistant to bacterial infections. B) Mixing a heat-killed pathogenic strain of bacteria with a living nonpathogenic strain can convert some of the living cells into the pathogenic form. C) Mixing a heat-killed nonpathogenic strain of bacteria with a living pathogenic strain makes the pathogenic strain nonpathogenic. D) Infecting mice with nonpathogenic strains of bacteria makes them resistant to pathogenic strains.

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

1) 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.

B) The 5' to 3' direction of one strand runs counter to the 5' to 3' direction of the other strand.

10) What is meant by the description "antiparallel" regarding the two strands of nucleic acids that make up DNA? A) The twisting nature of DNA creates nonparallel strands. B) The 5' to 3' direction of one strand runs counter to the 5' to 3' direction of the other strand. C) Base pairings create unequal spacing between the two DNA strands. D) One strand contains only purines and the other contains only pyrimidines.

B) Prokaryotic chromosomes have a single origin of replication, whereas eukaryotic chromosomes have many.

11) Which of the following statements describes one difference between DNA replication in prokaryotes and DNA replication in eukaryotes? A) Prokaryotic chromosomes have histones, whereas eukaryotic chromosomes do not. B) Prokaryotic chromosomes have a single origin of replication, whereas eukaryotic chromosomes have many. C) The rate of elongation during DNA replication is slower in prokaryotes than in eukaryotes. D) Prokaryotes produce Okazaki fragments during DNA replication, but eukaryotes do not. E) Prokaryotes have telomeres, and eukaryotes do not.

C) 5' RNA nucleotides, DNA nucleotides 3'

13) An Okazaki fragment has which of the following arrangements? A) primase, polymerase, ligase B) 3' RNA nucleotides, DNA nucleotides 5' C) 5' RNA nucleotides, DNA nucleotides 3' D) DNA polymerase I, DNA polymerase III E) 5' DNA to 3'

C) DNA polymerase III

15) 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) 5'-A C G U U A G G-3'

16) At a specific area of a chromosome, the following sequence of nucleotides is present where the chain opens to form a replication fork: 3'-C C T A G G C T G C A A T C C-5' An RNA primer is formed starting at the underlined T (T) of the template. Which of the following represents the primer sequence? A) 5'-G C C T A G G-3' B) 3'-G C C T A G G-5' C) 5'-A C G T T A G G-3' D) 5'-A C G U U A G G-3' E) 5'-G C C U A G G-3'

E) nuclease, DNA polymerase, DNA ligase

18) In which order do the necessary enzymes act to repair a thymine dimer by nucleotide excision repair? A) nuclease, DNA polymerase, RNA primase B) helicase, DNA polymerase, DNA ligase C) DNA ligase, nuclease, helicase D) DNA polymerase, RNA polymerase, DNA ligase E) nuclease, DNA polymerase, DNA ligase

C) to add nucleotides to the 3' end of a growing DNA strand

19) What is the function of DNA polymerase III? A) to unwind the DNA helix during replication B) to seal together the broken ends of DNA strands C) to add nucleotides to the 3' end of a growing DNA strand D) to degrade damaged DNA molecules E) to rejoin the two DNA strands (one new and one old) after replication

E) assimilation of external DNA into a cell

2) How is transformation in bacteria most accurately described? A) the creation of a strand of DNA from an RNA molecule B) the creation of a strand of RNA from a DNA molecule C) the infection of cells by a phage DNA molecule D) the type of semiconservative replication shown by DNA E) assimilation of external DNA into a cell

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

2) 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) leading strands and Okazaki fragments.

2) 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 A) leading strands and Okazaki fragments. B) lagging strands and Okazaki fragments. C) Okazaki fragments and RNA primers. D) leading strands and RNA primers. E) RNA primers and mitochondrial DNA.

A) the nucleoside triphosphates have the sugar deoxyribose; ATP has the sugar ribose.

20) The difference between ATP and the nucleoside triphosphates used during DNA synthesis is that A) the nucleoside triphosphates have the sugar deoxyribose; ATP has the sugar ribose. B) the nucleoside triphosphates have two phosphate groups; ATP has three phosphate groups. C) ATP contains three high-energy bonds; the nucleoside triphosphates have two. D) ATP is found only in human cells; the nucleoside triphosphates are found in all animal and plant cells. E) triphosphate monomers are active in the nucleoside triphosphates, but not in ATP.

A) the leading strand is synthesized in the same direction as the movement of the replication fork, and the lagging strand is synthesized in the opposite direction.

21) The leading and the lagging strands of DNA formed during DNA replication differ in that A) the leading strand is synthesized in the same direction as the movement of the replication fork, and the lagging strand is synthesized in the opposite direction. B) the leading strand is synthesized by adding nucleotides to the 3' end of the growing strand, and the lagging strand is synthesized by adding nucleotides to the 5' end. C) the lagging strand is synthesized continuously, whereas the leading strand is synthesized in short fragments that are ultimately stitched together. D) the leading strand is synthesized at twice the rate of the lagging strand.

D) DNA polymerase can only add nucleotides to the free 3' end.

22) A new DNA strand elongates only in the 5' to 3' direction because A) DNA polymerase begins adding nucleotides at the 5' end of the template. B) Okazaki fragments prevent elongation in the 3' to 5' direction. C) replication must progress toward the replication fork. D) DNA polymerase can only add nucleotides to the free 3' end.

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

23) 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) It joins Okazaki fragments together.

24) What is the role of DNA ligase in the elongation of the lagging strand during DNA replication? A) It synthesizes RNA nucleotides to make a primer. B) It catalyzes the lengthening of telomeres. C) It joins Okazaki fragments together. D) It unwinds the parental double helix. E) It stabilizes the unwound parental DNA.

D) single-strand binding proteins

25) 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) They cannot repair thymine dimers.

26) Individuals with the disorder xeroderma pigmentosum are hypersensitive to sunlight. This occurs because their cells are impaired in what way? A) They cannot replicate DNA. B) They cannot undergo mitosis. C) They cannot exchange DNA with other cells. D) They cannot repair thymine dimers. E) They do not recombine homologous chromosomes during meiosis.

D) DNA polymerase I

27) During DNA replication, which of the following enzymes removes the RNA nucleotides from the primer and adds equivalent DNA nucleotides to the 3' end of Okazaki fragments? A) helicase B) DNA polymerase III C) ligase D) DNA polymerase I E) primase

A) helicase

28) 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

C) ligase

29) During DNA replication, which of the following enzymes covalently connects segments of DNA? A) helicase B) DNA polymerase III C) ligase D) DNA polymerase I E) primase

D) Descendants of the living cells are also phosphorescent.

3) 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? A) DNA passed from the heat-killed strain to the living strain. B) Protein passed from the heat-killed strain to the living strain. C) The phosphorescence in the living strain is especially bright. D) Descendants of the living cells are also phosphorescent. E) Both DNA and protein passed from the heat-killed strain to the living strain.

B) A + G = C + T

3) 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

E) primase

30) Which of the following enzymes synthesizes short segments of RNA? A) helicase B) DNA polymerase III C) ligase D) DNA polymerase I E) primase

C) the ability to excise damage to single-stranded DNA and replace it.

31) Given the damage caused by UV radiation, the kind of gene affected in those with xeroderma pigmentosum is one whose product is involved with A) mending of double-strand breaks in the DNA backbone. B) breakage of cross-strand covalent bonds. C) the ability to excise damage to single-stranded DNA and replace it. D) the removal of damaged areas of double-stranded DNA. E) causing affected skin cells to undergo apoptosis.

A) double-stranded DNA, four kinds of DNA nucleotides, primers, origins of replication

32) Which of the following sets of materials is required by both eukaryotes and prokaryotes for DNA replication? A) double-stranded DNA, four kinds of DNA nucleotides, primers, origins of replication B) topoisomerases, telomerases, polymerases C) G-C rich regions, polymerases, chromosome nicks D) nucleosome loosening, four kinds of DNA nucleotides, four kinds of RNA nucleotides E) ligase, primers, nucleases

D) the 30-nm chromatin fiber

33) In a linear eukaryotic chromatin sample, which of the following strands is looped into domains by scaffolding? A) DNA without attached histones B) DNA with H1 only C) the 10-nm chromatin fiber D) the 30-nm chromatin fiber

D) It consists of a single linear molecule of double-stranded DNA plus proteins.

34) Which of the following statements best describes the eukaryotic chromosome? A) It is composed of DNA alone. B) The nucleosome is its most basic functional subunit. C) The number of genes on each chromosome is different in different cell types of an organism. D) It consists of a single linear molecule of double-stranded DNA plus proteins.

A) The cell's DNA couldn't be packed into its nucleus.

35) If a cell were unable to produce histone proteins, which of the following would be a likely effect? A) The cell's DNA couldn't be packed into its nucleus. B) Spindle fibers would not form during prophase. C) Expression of other genes would compensate for the lack of histones. D) DNA polymerase I would not function properly.

B) Histone H1 is not present in the nucleosome bead; instead, it draws the nucleosomes together.

36) Which of the following statements correctly describes one characteristic of histones? A) Each nucleosome consists of two molecules of histone H1. B) Histone H1 is not present in the nucleosome bead; instead, it draws the nucleosomes together. C) The carboxyl end of each histone extends outward from the nucleosome and is called a "histone tail." D) Histones are found in mammals, but not in other animals or in plants or fungi.

A) Histones are positively charged, and DNA is negatively charged.

37) Why do histones bind tightly to DNA? A) Histones are positively charged, and DNA is negatively charged. B) Histones are negatively charged, and DNA is positively charged. C) Both histones and DNA are strongly hydrophobic. D) Histones are covalently linked to the DNA. E) Histones are highly hydrophobic, and DNA is hydrophilic.

A) nucleosome, 30-nm chromatin fiber, looped domain

38) Which of the following lists of structures correctly represents the order of increasingly higher levels of organization of chromatin? A) nucleosome, 30-nm chromatin fiber, looped domain B) looped domain, 30-nm chromatin fiber, nucleosome C) looped domain, nucleosome, 30-nm chromatin fiber D) nucleosome, looped domain, 30-nm chromatin fiber E) 30-nm chromatin fiber, nucleosome, looped domain

C) Heterochromatin is highly condensed, whereas euchromatin is less compact.

39) Which of the following statements correctly describes chromatin? A) Heterochromatin is composed of DNA, whereas euchromatin is made of DNA and RNA. B) Both heterochromatin and euchromatin are found in the cytoplasm. C) Heterochromatin is highly condensed, whereas euchromatin is less compact. D) Euchromatin is not transcribed, whereas heterochromatin is transcribed.

B) DNA contains phosphorus, whereas protein does not.

4) In trying to determine whether DNA or protein is the genetic material, Hershey and Chase made use of which of the following facts? A) DNA contains sulfur, whereas protein does not. B) DNA contains phosphorus, whereas protein does not. C) DNA contains nitrogen, whereas protein does not. D) DNA contains purines, whereas protein includes pyrimidines. E) RNA includes ribose, whereas DNA includes deoxyribose sugars.

D) depends on the action of DNA polymerase.

4) 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.

C) increasing the length of the DNA fragment

40) Which of the following modifications is most likely to alter the rate at which a DNA fragment moves through a gel during electrophoresis? A) altering the nucleotide sequence of the DNA fragment without adding or removing nucleotides B) radioactively labeling the cytosine bases within the DNA fragment C) increasing the length of the DNA fragment D) leaving the length of the DNA fragment the same

D) Erwin Chargaff

5) 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.

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

A) 8%

6) Cytosine makes up 42% of the nucleotides in a sample of DNA from an organism. Approximately what percentage of the nucleotides in this sample will be thymine? A) 8% B) 16% C) 31% D) 42%

B) GGCC CCGG

6) Which of the following sequences in double-stranded DNA is most likely to be recognized as a cutting site for a restriction enzyme? A) AAGG TTCC B) GGCC CCGG C) ACCA TGGT D) AAAA TTTT

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

7) 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

B) DNA ligase

8) 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

A) the sequence of bases

8) It became apparent to Watson and Crick after completion of their model that the DNA molecule could carry a vast amount of hereditary information based on which of the following characteristics? A) the sequence of bases B) phosphate-sugar backbones C) complementary pairing of bases D) different five-carbon sugars

C) A + C = G + T

9) In an analysis of the nucleotide composition of DNA, which of the following will be found? A) A = C B) A = G and C = T C) A + C = G + T D) G + C = T + A

A) nuclease, DNA polymerase, DNA ligase

9) 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

C) to find which of the students has which alleles

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. 6) Why might they be conducting such an experiment? A) to find the location of this gene in the human genome B) to prepare to isolate the chromosome on which the gene of interest is found C) to find which of the students has which alleles D) to collect population data that can be used to assess natural selection

B) The two students who have two fragments have one restriction site in this region.

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. 7) 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? A) Each pair of students has a different gene for this function. B) The two students who have two fragments have one restriction site in this region. C) The two students who have two fragments have two restriction sites within this gene. D) Each of these students is heterozygous for this gene.