Chapter 16

18) What kind of chemical bonds are found between paired bases of the DNA double helix? A) hydrogen B) ionic C) covalent D) sulfhydryl E) phosphate

A) hydrogen

44) Which of the following is least related to the others in the list? A) nuclea gase primase helicase ymera Answer

A) nuclease

The spontaneous loss of amino from adenine results in hypoxanthine, arn unnatural base, opposite thymine. What combination of molecules could the cell use to repair such damage? A) nuclease, DNA polymerase, DNA ase B) telomerase, primase, DNA polymerase C) telomerase, helicase, single-strand binding protein D)DNA ligase, replication fork adenase E) nuclease, telomerase, primase

A) nuclease, DNA polymerase, DNA ase

24) A space probe returns with a culture of a microorganism found on a distant planet. Analysis shows that it is a carbon-based life form that has DNA. You grow the cells in 15N medium for several generations and then transfer it to 14N medium. Which pattern in Figure 16.1 would you expect if the DNA was replicated in a conservative manner?

B

35) In DNA, the designations 3' and 5' refer phosphate groups may bond A) carbon atoms of deoxyribose to which B) carbon or nitrogen atoms on the rings of purine or pyrimidine bases. C) cross-linking of the third and fifth carbon atoms of deoxyribose. D) bonding between purines and deoxyribose and between pyrimidines and deoxyribose. E) bonds that form between adenine and thymine and between guanine and cytosine.

phosphate groups may bond A) carbon atoms of deoxyribose to which

What enzyme catalyzes the unwinding a DNA double helix? A) helicase B) primase C) ligase D) single-stranded binding protein E) DNA polymerase

A) helicase

20) It became apparent to Watson and Crick after completion of their model that the DNA molecule could carry a vast amount of hereditary information in its A) sequence of bases B) phosphate-sugar backbones. C) complementary pairing of bases. D) side groups of nitrogenous bases. E) different five-carbon sugars.

A) sequence of bases

) Cytosine makes up 38 % of the nucleotides in a sample of DNA from an organism. What percent of the nucleotides in this sample will be thymine? A)12 B) 24 C)31 D)38 E) It cannot be determined from the information provided.

A)12

13) In any DNA sample, the amount of adenine equals the amount of thymine and the amount of guanine equals the amount of cytosine

D. Chargaf

46) Which of these mechanisms ensures that DNA replication is accurate? A) proofreading B) mismatch repair C) excision repair D) complementary base pairing E) all of the above

E) all of the above

Place the scientists' names in the correct chronological order, starting with the oldest contribution.

12354

5) Which of the following names is least related to the others? A) Griffith B) Avery C) Meselson D) Watson E) Hershey

A) Griffith

14) What happens when T2 phages are grown in the presence of radioactive phosphorus? A) Their DNA becomes radioactive. B) Their proteins become radioactive. C) Their DNA is found to be of medium density in a centrifuge tube. D) They are no longer able to transform bacterial cells E) They transfer their radioactivity to E coli chromosomes during infection.

A) Their DNA becomes radioactive.

41) What is the function of DNA ligase? A) covalent bonding of the 3' end of a new DNA fragment to the 5' end ofa growing chain B) elongation of new DNA at a replication fork by addition of nucleotides to the existing chain C) the addition of methyl groups to bases of DNA D) unwinding of the double helix E) Both B and C are correct.

A) covalent bonding of the 3' end of a new DNA fragment to the 5' end ofa growing chain

52) One type of virus that infects bacteria is called a(n) A) phage B) mage. C) rhinovirus. D) filovirus. E) Ebola

A) phage

4) Tobacco mosaic virus has RNA rather than DNA as its genetic material. In a hypothetical situation where RNA from a tobacco mosaic virus is mixed with proteins from a related DNA virus, the result could be a hybrid virus. If that virus were to infect a cell and reproduce, what would the resulting "offspring" viruses be like? A) tobacco mosaic virus B) the related DNA virus C) a hybrid: tobacco mosaic virus RNA and protein from the DNA virus D) a hybrid: tobacco mosaic virus protein and nucleic acid from the DNA virus E) a virus with a double helix made up of one strand of DNA complementary to a strand of RNA surrounded by viral

A) tobacco mosaic virus

40) What is the primer that is required to initiate the synthesis of a new DNA strand? A)RNA B) DNA C) protein D) ligase E) primase

A)RNA

The primer that initiates synthesis of a new DNA strand is usually A)RNA. B) DNA. C) an Okazaki fragment. D) a structural protein. E) a thymine dimer.

A)RNA.

29) enhances separation of DNA strands during replication

A. helicase

33) The difference between ATP and nucleoside triphosphate is that A)NTP has the sugar deoxyribose; ATP has the sugar ribose. B) NTP has 2 phosphate groups white ATP has 3 phosphate groups C) ATP contains 3 high-energy bonds while NTP has 2. D) ATP is only found in human cells while the other is negatively charged. E) triphosphate monomers are active in NTP but not ATP

B) NTP has 2 phosphate groups white ATP has 3 phosphate groups

15) When T2 phage viruses that infect bacteria make more viruses in the presence of radioactive sulfur, which of the following results? A) The viral DNA is tagged by radioactivity B) The viral proteins are tagged by radioactivity C) The viral DNA is found to be of medium density in a centrifuge tube. E. coli DTheynfer DNA their radioactiviy to E) Both the viral DNA and the viral proteins are tagged by radioactivity

B) The viral proteins are tagged by radioactivity

47) In making a movie, sometimes an editor another. will cut out This is analogous one piece of film to which and insert of the following? A) mismatch repair B) excision repair C) transformation repair D) recombinational repair E) telomerase repair

B) excision repair

A biochemist isolates and purifies various molecules needed for DNA replication. When she adds some DNA, replication occurs, but the DNA molecules formed are defective. Each consists of a normal DNA strand paired with numerous segments of DNA a few hundred nucleotides long. What has she probably left out of the mixture? A)DNA polymerase B) ligase C) nucleotides D) Okazaki fragments E) primers

B) ligase

53) DNA and RNA are polymers of A) fatty acids. B) nucleotides C) monoglycerides D) amino acids. E) monosaccharides.

B) nucleotides

2) Which of the following is least related to the others in the list? A) transformation B) phage C)DNA D) Griffith E) Avery

B) phage

49) Which of the following is analogous to telomeres? A) the pull tab on a soft-drink can B) the two ends of a shoe lace C) the center spindle that a compact disk fits around while in the case D) the mechanism of a zipper that allows the separated parts to be joined E) the correct letters used to replace errors in a document after they have been deleted in a word processor

B) the two ends of a shoe lace

Of the following, the most reasonable inference from the observation that defects in DNA repair enzymes contribute to some forms of cancer is that A) cancer is generally inherited. B) uncorrected changes in DNA can cause cancer C) cancer cannot occur when DNA repair enzymes work properly D)mutations generally lead to cancer E) cancer is caused by environmental factors that damage DNA repair enzymes.

B) uncorrected changes in DNA can cause cancer

12) The DNA of a phage was injected into the outside. The viral DNA directed the host bacterial host, but the protein coat stayed to replicate new phage viruses.

B. Hershey and Chase

A eukaryotic cell lacking telomerase would A) be unable to take up DNA from the surrounding solution. B) be unable to identify and correct mismatched nucleotides in its daughter DNA strands. C) experience a gradual reduction of chromosome length with each replication cycle D)have a greater potential to become cancerous. E) incorporate one extraneous nucleotide for each Okazaki fragment added.

C) experience a gradual reduction of chromosome length with each replication cycle

42) What is the role of DNA ligase in the elongation of the lagging strand during DNA replication? A) synthesize RNA nucleotides to make a primer B) catalyze the lengthening of telomeres C) join Okazaki fragments together D) unwind the parental double helix E) stabilize the unwound parental DNA

C) join Okazaki fragments together

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 C) some chemical from pathogenic cells was transferred to nonpathogenic cells, making them pathogenic. D) the polysaccharide coat of bacteria caused pneumonia. E) bacteriophages injected DNA into bacteria.

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

27) Which of the following is least related to the others in the list? A) Okazaki fragments B) replication fork C) telomerase D) DNA polymerases E) semiconservative

C) telomerase

39) Which of the following is least related to the others in the list? A) Okazaki fragment B) primer C) telomere D) leading strand E) lagging strand

C) telomere

17) All of the following were determined directly from X-ray diffraction photographs of crystallized DNA except À) the diameter of the double helix B) the helical shape of DNA. C) the sequence of nucleotides. D) the linear distance required for one full turn of the double helix E) the width of the helix.

C) the sequence of nucleotides.

If radioactive sulfur (35s) is used in a culture medium of bacteria that contains phage viruses, it will later appear in the A) viral DNA. B) bacterial RNA. C) viral coats. D) viral RNA. E) bacterial cell wall.

C) viral coats.

21) In an analysis of the nucleotide composition of DNA, which of the following is true? A)A C BJA - Gand C T C)A+C-G+ T D)A +T G+C E) Both B and C are true.

C)A+C-G+ 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+T E ) G = T

C)A+T-G+T

60) What is the basis for the difference in the synthesis of the leading and lagging strands of DNA molecules? A) The origins of replication occur only at the 5' end. B) Helicases and single-strand binding proteins work at the 5' end. C)DNA polymerase can join new nucleotides only to the 3'end of a growing strand. D)DNA ligase works only in the 3'- direction. E) Polymerase can only work on one strand at a time.

C)DNA polymerase can join new nucleotides only to the 3'end of growing strand.

25) Which enzymes catalyze the elongation of a DNA strand in the 5 3' direction? A) primase B) DNA ligase C)DNA polymerases D) topoisomerase E) helicase

C)DNA polymerases

26) What is the function of DNA polymerase? A) to unwind the DNA helix during replication B) to seal together the broken ends of DNA strands C)to add nucleotides to the 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

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

11) Chemicals from heat-killed S cells were purified. The chemicals were tested for the ability to transform live R cells. The transforming agent was found to be DNA.

C. Avery, MacLeod, and McCarty

23) In the late 1950s Meselson and Stahl grew bacteria in a medium containing "heavy" nitrogen (15N) and then transferred them to a medium containing 14N. Which of the results in Figure 16.1 would be expected after one DNA replication in the presence of 14N?

D

For a couple of decades, biologists knew the nucleus contained DNA and proteins. The prevailing opinion was that proteins were the genetic material and DNA. The reason for this belief was that proteins were more complex than DNA. This is because A) proteins have a greater variety of three-dimensional forms than does DNA. B) proteins have two different levels of structural organization; DNA has four. C) proteins are made of 20 amino acids and DNA is made of four nucleotides D) A and Conly are correct. E)A, B, and C are correct.

D) A and Conly are correct.

19) All of the following statements apply to the Watson and Crick model of DNA except A) The two strands of the DNA form a double helix. B) The distance between the strands of the helix is uniform. C) The framework of the helix consists of sugar-phosphate units of the nucleotides. D) The two strands of the helix are held together by covalent bonds. E) The purines are attracted to pyrimidines.

D) The two strands of the helix are held together by covalent bonds.

36) The two strands of a DNA molecule run in opposite directions. The 3' and 5' ends of one strand are opposite the 5' and 3' ends of the complementary strand. This is analogous to A) a photograph and a photographic negative B) one side of a divided highway C) a baseball and a bat. D) an "up" escalator next to a "down" escalator. E) both A and C.

D) an "up" escalator next to a "down" escalator.

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 E) does not require a template strand.

D) depends on the action of DNA polymerase

43) All of the A)covalently adding nucleotides to the polymerase in DNA replication except following are functions of DNA new strands. B) proofreading each added nucleotide for correct base pairing. D) initiating a polynucleotide strand. C)replacing RNA primers with DNA.

D) initiating a polynucleotide strand.

48) In the following list of DNA properties, which relates to the disorder xeroderma pigmentosum? A) replication B) information storage G) exchange with other organisms D) repair of thymine dimers E) mutation

D) repair of thymine dimers

45) Which of the following help to hold the DNA strands apart while they are being replicated? A) helicase B) ligase C)DNA polymerase D) single-stranded binding proteins E) exonuclease

D) single-stranded binding proteins

7) All of the following elements are present in DNA except A)oxy B) nitrogen. C) carbon D) sulfur E) phosphorus.V

D) sulfur

51) A eukaryotic cell lacking telomerase would A) have a high probability of becoming cancerous. B) produce Okazaki fragments. C) be unable to replicate D) undergo a reduction in chromosome length. E) be highly sensitive to sunlight.

D) undergo a reduction in chromosome length.

8) In trying to determine whether DNA or protein was the genetic material, Al Hershey and Martha Chase made use of which of the following facts? A)DNA does not contain sulfur, whereas protein does. B)DNA contains phosphorus, but protein does not C)DNA contains greater amounts of nitrogen than does protein. D)A and B only are correct E) A, B, and C are correct.

D)A and B only are correct

ell grown on 13N medium are transferred to 14N medium and allowed to grow for two 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) one low-density band

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

28) catalyzes synthesis of a new strand of DNA

D. DNA polymerase

new DNA strand? 5 到 what enzyme catalyzes the elongation of A) helicase B) primase C) ligase D) single-stranded binding protein E) DNA polymerase

E) DNA polymerase

37) A new DNA strand only elongates in the 5 to 3' direction because A)DNA polymerase begins adding nucleotides at the 5' end. B) Okazaki fragments prevent elongation in the 3' to 5 direction. C) the polarity of the DNA molecule prevents addition of nucleotides at the 3' end. D) replication must progress toward the replication fork. E) DNA polymerase adds nucleotides only to the free 3' end.

E) DNA polymerase adds nucleotides only to the free 3' end.

54) Which of these is always true with regard to a DNA double helix? A) The amount of adenine is equal to the amount of uracil, and the amount of guanine is equal to the amount of cytosine. B) The amount of adenine is equal to the amount of thymine, and the amount of guanine is equal to the amount of uracil. C)The amount of adenine is equal to the amount of guanine, and the amount of thymine is equal to the amount of cytosine D) The amount of adenine is equal to the amount of cytosine, and the amount of guanine is equal to the amount of thymine E) The amount of adenine is equal to the amount of thymine, and the amount of guanine is equal to the amount of cytosine

E) The amount of adenine is equal to the amount of thymine, and the amount of guanine is equal to the amount of cytosine

10) For a science fair project, two students decided to repeat the-Hershey and Chase experiment, with modifications. They decide that labeling the phosphates of the DNA wasn't good enough. Each nucleotide has only one phosphate whereas each has two to five nitrogens. Thus, iabeling the nitrogens wouid provide a stronger label than labeling the phosphates. This experiment will not work because A) there is no radioactive isotope of nitrogen. B) radioactive nitrogen has a half-life of 100,000 years and the material would be too dangerous for too long. C) Meselson and Stahl already did this experiment. D) although there are more nitrogens in a nucleotide, labeled phosphates actually have 16 extra neutrons, so they are more radioactive. E) amino acids (and thus proteins) also have nitrogen atoms, thus the radioactivity would not distinguish between DNA and proteins.

E) amino acids (and thus proteins) also have nitrogen atoms, thus the radioactivity would not distinguish between DNA and proteins.

3) What does transformation involve in bacteria? 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

E) assimilation of external DNA into a cell

22) Suppose one were provided with an actively dividing culture of E. coli bacteria to which radioactive thymine had been added. What would happen if a cell replicated once in the presence of this radioactive base? A)One of the daughter cells, but not the other, would have radioactive DNA. B) Neither of the two daughter cells would be radioactive. C) All four bases of the DNA would be radioactive. D) Radioactive thymine would pair with nonradioactive guanine. E)DNA in both daughter cells would be radioactive

E)DNA in both daughter cells would be radioactive

38) The problem of replicating the lagging the 3'- 5 direction-requires which of the strand of DNA-that is, adding bases in following? A)DNA ligase B)RNA primers C) Okazaki fragments D)A and B only EJA , B , and C

EJA , B , and C

30) covalently connects segments of DNA

Ligase

32) a DNA-cutting enzyme in the repair of damage to DNA

Nuclase

31) synthesizes short segments of RNA

Primase