Ch. 11 Nucleic Acid Structure, DNA Replication, and Chromosome Structure Study Questions and Answers

55) Which of the following statements is TRUE? A) Many active genes are found in euchromatin, because proteins involved in transcription can easily access these regions of DNA. B) Euchromatin, found in interphase cells, is readily visible and easily viewed. C) A region of DNA is either heterochromatin or euchromatin, it cannot go back and forth between the two forms. D) When DNA is being replicated, the chromosomes are composed chiefly of heterochromatin. E) All of the answers are correct.

A) Many active genes are found in euchromatin, because proteins involved in transcription can easily access these regions of DNA.

12) Which of the following statements about DNA is FALSE? A) One chromosome is made up of many DNA molecules. B) A eukaryotic genome is made up of many DNA molecules. C) A DNA double helix contains both covalent bonds and hydrogen bonds. D) A strand of DNA is made up of many nucleotides. E) All of these are TRUE.

A) One chromosome is made up of many DNA molecules.

53) Where would one expect to find the most telomerase? A) male germ cells that give rise to gametes B) skin cells from a 60-year-old individual C) skin cells from a 2-year-old individual D) a nerve cell from a 60-year-old individual E) a nerve cell from a 2-year-old individual

A) male germ cells that give rise to gametes

33) Which of the following is NOT a protein involved in DNA replication? A) replication fork B) single-stranded binding proteins C) DNA ligase D) topoisomerase E) helicase

A) replication fork

21) A DNA specimen that contains 30% guanine has ________ thymine. A) 15%. B) 20%. C) 30%. D) 60%. E) The amount of thymine cannot be determined.

B) 20%.

13) Which of the following relationships about nucleotide composition in DNA is TRUE? A) C G=A T B) C A=G T C) C=A D) G=T E) C=T

B) C+A = G+T

40) Which molecule is responsible for separating double-stranded DNA into single strands? A) DNA primase B) DNA helicase C) topoisomerase D) DNA ligase E) single-stranded binding proteins

B) DNA helicase

39) All of the following are critical factors for DNA replication on the leading strand except A) primer B) DNA ligase C) DNA polymerase D) DNA primase E) deoxynucleotide triphosphates

B) DNA ligase

3) Type S Streptococcus pneumoniae bacterium is lethal and will kill its host. If heat inactivated the S strain dies and becomes nonlethal. Type R Streptococcus pneumoniae is a nonvirulent strain of bacteria. What would occur if one were to inject both the R strain and heat-killed S strains into a host organism such as the mouse? A) The S strain would be transformed into the nonvirulent R strain and kill the host. B) The R strain would be transformed into the virulent S strain and kill the host. C) The S strain would be transformed into the nonvirulent R strain and not affect the host. D) The R strain would be transformed into the virulent S strain and not affect the host. E) Neither the S nor the R strain would change.

B) The R strain would be transformed into the nonvirulent S strain and kill the host.

38) Which molecule catalyzes covalent bond formation between fragments of DNA? A) helicase B) ligase C) polymerase D) primase E) nuclease

B) ligase

10) Beginning with the simplest level of structure, which order of organization of genetic material is CORRECT? A) DNA, nucleotide, gene, genome, chromosome B) nucleotide, DNA, gene, chromosome, genome C) DNA, nucleotide, gene, chromosome, genome D) nucleotide, DNA, gene, genome, chromosome E) nucleotide, DNA, chromosome, gene, genome

B) nucleotide, DNA, gene, chromosome, genome

34) How many replication forks are there at an origin of replication? A) one B) two C) three D) four E) five

B) two

32) Reverse transcriptase is an enzyme that can synthesize DNA from an RNA template. What DNA sequence is produced from an RNA molecule with the sequence 5'AUUGACGGU3'? A) 3'UAACUGCCA5' B) 5'TTTCTGCCT3' C) 3'TAACTGCCA5' D) 5'ATTCAGCCT3' E) 3'TUUCTGCCU5'

C) 3'TAACTGCCA5'

5) Who discovered that DNA was the genetic material or transforming factor that could convert nonvirulent R-type Streptococcus pneumoniae bacterium to the virulent S-type? A) Weismann and Nageli B) Griffith C) Avery, MacLeod, and McCarty D) Hershey and Chase E) Watson, Crick, Wilkins, and Franklin

C) Avery, MacLeod, and McCarty

4) Griffith first proposed the "transformation principal" through his studies on Streptococcus pneumoniae bacterium. Which of the following molecules was later found to be responsible for this phenomenon? A) protein B) RNA C) DNA D) phage E) bacteriophage

C) DNA

37) Which of the following statements best describes DNA polymerase? A) It is an enzyme required to produce a primer needed for DNA replication. B) It is an enzyme that catalyzes the addition of nucleotides to the 5′ end of a growing DNA strand. C) It is an enzyme that catalyzes the addition of nucleotides to the 3′ end of a growing DNA strand. D) It is an enzyme required to glue pieces of DNA fragments together. E) It is an enzyme that polymerizes the DNA and keeps the replication fork open.

C) It is an enzyme that catalyzes the addition of nucleotides to the 3' end of a growing DNA strand.

44) Which of the following statements about DNA replication is INCORRECT? A) It begins at multiple origins of replication sites along eukaryotic chromosomes. B) It proceeds with the addition of new nucleotides to the 3′ end of a growing DNA strand. C) It is powered by the hydrolysis of ATP. D) Each strand within the DNA double helix is used as a template for synthesis of a new strand. E) It requires that both strands of the double helix be separated from each other.

C) It is powered by the hydrolysis of ATP.

46) ________ are made in replicating the lagging strand of DNA, but are not made during leading strand DNA replication. A) primers B) nucleases C) Okazaki fragments D) pyrophosphates E) DNA polymerases

C) Okazaki fragments

51) The enzyme that attaches DNA nucleotides at the ends of eukaryotic chromosomes in order to prevent chromosome shortening is called A) Polymerase. B) Ligase. C) Telomerase. D) Topoisomerase. E) Primase.

C) Telomerase.

18) Which of the following statements about the structure or composition of DNA is FALSE? A) DNA is a double helix B) Complementary base-pairing occurs between pyrimidine and purine bases C) The amount of thymine closely approximates that of guanine within a particular organism D) Each nucleotide within a DNA strand is separated by about 0.34 nm E) Adenine pairs with thymine and guanine with cytosine

C) The amount of thymine closely approximates that of guanine within a particular organism

50) Some bacteria have been found to have much higher rates of mutation than other members of their population; they are termed "mutators." What do you think is the most likely reason for their higher rates of mutation? A) They have much smaller genomes than regular bacteria. B) They are incapable of bacterial transformation. C) Their DNA polymerase has compromised 3' to 5' exonuclease function. D) Their DNA polymerase has compromised 5' to 3' polymerase function. E) All choices are equally likely to lead to higher rates of mutation.

C) Their DNA polymerase has compromised 3' to 5' exonuclease function.

20) What was one of the pieces of evidence most critical to the discovery of DNA structure? A) its composition of four different nucleotides B) the discovery of its semi-conservative mode of replication C) an X-ray diffraction pattern suggesting a double helix shape D) the backbone containing sugar-phosphate linkages E) the hydrogen bonding between different nucleotides

C) an X-ray diffraction pattern suggesting a double helix shape

25) Bacteria are grown in 15N (heavy) medium and then transferred to 14N (light) medium and are allowed to replicate for one generation. The DNA is subsequently isolated and centrifuged in a CsCl2 gradient to yield what type of gradient band(s)? A) one heavy band B) one light band C) one half-heavy (intermediate to heavy and light) band D) one heavy and one half-heavy band E) one heavy and one light band

C) one half-heavy (intermediate to heavy and light) band

14) The nucleotides within DNA are composed of a A) phosphate group, ribose sugar, and a nitrogenous base. B) sulfur group, ribose sugar, and a nitrogenous base. C) phosphate group, deoxyribose sugar, and a nitrogenous base. D) sulfur group, deoxyribose sugar, and a nitrogenous base. E) phosphate group, hexose sugar, and a nitrogenous base.

C) phosphate group, deoxyribose sugar, and a nitrogenous base.

27) In a single strand of DNA, nucleotides are connected by which type of bond? A) hydrogen B) peptide C) phosphodiester D) purine E) ionic

C) phosphodiester

24) The mechanism of DNA replication is A) conservative. B) intermediate. C) semiconservative. D) dispersive. E) complementary.

C) semiconservative.

31) What is the complementary DNA strand to 5′-ATTCGGTGA-3′? A) 5′-TAAGCCACT-3′ B) 3′-CGGATTGTC-5′ C) 5′-CGGATTGTC-3′ D) 3′-TAAGCCACT-5′ E) 3′-ATTCGGTGA-5′

D) 3'-TAAGCCACT-5'

16) Which of the following is FALSE when comparing RNA and DNA? A) Both contain nucleotides connected by phosphodiester linkages. B) Both contain phosphate groups. C) Both are composed of nucleotides that contain sugars. D) Both are composed of identical nucleotides. E) Both are composed of nucleotides that contain a phosphate group, a pentose sugar, and a nitrogenous base. F) Both have a 5' end and a 3' end. G) Both are composed of purines and pyrimidines.

D) Both are composed of identical nucleotides.

7) Which of the following scientist-discoveries is mismatched? A) Watson, Crick, Wilkins, and Franklin-DNA structure. B) Avery, MacLeod, and McCarty-DNA is the genetic material. C) Meselson and Stahl-mechanism of DNA replication. D) Griffith-chromosomes.

D) Griffith-chromosomes.

56) Which of the following statements is TRUE? A) Interphase chromosomes are loosely compacted, overlapping, and intertwined with each other within the nucleus. B) Interphase chromosomes are loosely compacted and do not associate with histones until the cell is preparing to divide. C) Interphase chromosomes are also known as euchromatin. Condensed, metaphase chromosomes are also known as heterochromatin. D) Radial loop domains are formed due to interactions between 30 nm fibers and intermediate filaments. E) None of the answers are true.

D) Radial loop domains are formed due to interactions between 30 nm fibers and intermediate fibers.

52) Which of the following statements about telomeres is INCORRECT? A) Telomeres are lengthened by telomerase. B) Telomeres are found at the ends of chromosomes. C) Telomeres are short repeat sequences. D) Telomeres would be longer in cells of older than younger individuals. E) Telomeres are crucial to the viability of a cell that replicates often.

D) Telomeres are found at the ends of chromosomes.

8) The building blocks of DNA are A) genes. B) double helices. C) amino acids. D) nucleotides. E) chromosomes.

D) nucleotides.

1) Which of the following is NOT a criterion for an organism's genetic material? A) The genetic material must contain information necessary to construct a whole organism. B) The genetic material must be transmitted from parent to offspring. C) To transmit information the genetic material must be replicated. D) The genetic material must be dynamic, changing rapidly in response to changes in the environment. E) Genetic material must account for the known variation within each species and among different species.

D) the genetic material must be dynamic, changing rapidly in response to changes in the environment.

45) Which of the following proteins-functions is mismatched? A) DNA polymerase-DNA synthesis B) DNA polymerase-primer removal and replacement with DNA C) DNA primase-production of RNA primer D) topoisomerase-separates double-stranded DNA into single strands E) single-stranded binding proteins-prevents single DNA strands from reforming into a double helix

D) topoisomerase-separates double stranded DNA into single strands

22) Without the work of Rosalind Franklin, Watson and Crick would not have known A) which nucleotides could pair together. B) how many strands of DNA made up the molecule. C) the shape of the molecule. D) the width of the molecule. E) All of the answers are correct.

E) All of the answers are correct.

23) Without data from the base composition studies of Chargaff, what might Watson and Crick's modeling studies have erroneously concluded? A) Bases could pair with themselves (e.g., A with A, C with C). B) Any purine could pair with any purine. C) Any pyrimidine could pair with any pyrimidine. D) Any purine could pair with any purine and any pyrimidine could pair with any pyrimidine. E) Any purine could pair with any pyrimidine.

E) Any purine could pair with any pyrimidine.

43) The function(s) of DNA polymerase includes which of the following? A) DNA synthesis B) DNA proofreading C) removal of RNA primers and filling in the gaps D) DNA synthesis and proofreading E) DNA synthesis, DNA proofreading, and removal of RNA primers and filling in the gaps

E) DNA synthesis, DNA proofreading, and removal of RNA primers and filling in the gaps

49) Which of the following statements is TRUE? A) The leading strand is replicated continuously for the entire length of the chromosome, e.g. while the lagging strand has multiple origins of replication. B) The lagging strand is synthesized in a semiconservative fashion while the leading strand is synthesized in a conservative fashion. C) Synthesis of the lagging strand requires more DNA helicase enzymes than synthesis of the leading strand. D) The lagging strand has a higher mutation rate than the leading strand. E) None of the answers are true.

E) None of the answers are true.

9) Which of the following is the highest (or most complex) level of structure for genetic material? A) nucleotide B) double helix C) DNA D) gene E) chromosome

E) chromosome

26) Bacteria are grown in 15N (heavy) medium and then transferred to 14N (light) medium and are allowed to replicate for two generations. The DNA is subsequently isolated and centrifuged in a CsCl2 gradient to yield what type of gradient band(s)? A) one heavy band B) one light band C) one half-heavy (intermediate to heavy and light) band D) one heavy and one half-heavy band E) one light and one half-heavy band

E) one light and one half-heavy band

2) Which of the following characteristics of genetic material accounts for the need to get a flu vaccine every year, but a polio vaccine once in a lifetime? A) information B) replication C) transmission D) replication and transmission E) variation

E) variation

17) A strand of DNA is composed of nucleotide bases, sulfate groups, and sugars.

False

28) If the sequence for one strand of DNA is 3′-TCGATT-5′ then its complementary strand would have a sequence of 3′-AGCTAA-5′.

False

30) If there is a 28% adenine, then there must be 28% cytosine for the DNA composition of a particular organism.

False

6) Studies by Avery, MacLeod, and McCarty with different strains of bacteria and those by Hershey and Chase with T2 bacteriophage determined that proteins are highly complex molecules that form the genetic material for bacteria and viruses.

False

11) When considering the complexity of genetic material, multiple genes are found within a chromosome.

True

29) DNA is a double helix structure whose strands are held together by hydrogen bonds with A to T and C to G base pairing.

True

42) DNA helicase and topoisomerase are similar insofar as they promote the unwinding and uncoiling of DNA.

True

48) Okazaki fragments are sequences of DNA most often found on the lagging strand of DNA during DNA replication.

True

54) The progressive shortening of telomeres in DNA correlates with cell senescence

True

36) During DNA replication, all of the following proteins are important for separating the DNA strands and allowing movement of the replication fork EXCEPT A) DNA polymerase. B) helicase. C) topoisomerase. D) single-stranded binding proteins. E) both helicase and topoisomerase.

A) DNA polymerase.

41) ________ produces short sequences of RNA, which allows the polymerase to synthesize a new strand of DNA. A) DNA primase B) DNA helicase C) DNA polymerase D) DNA topoisomerase E) DNA ligase

A) DNA primase

47) Why is there a need to produce Okazaki fragments on the lagging strand, but not on the leading strand of DNA? A) The two parental strands of DNA are antiparallel and DNA polymerase makes DNA in the 5′ to 3′ direction only. B) It is substantially more efficient to make several shorter strands rather than one longer strand of DNA. C) There is not enough cellular DNA ligase for bonding Okazaki fragments together if they were produced from both parental strands. D) By having one leading strand and one lagging strand the cell can limit the amount of DNA polymerase used for chromosomal replication. E) The leading strand opens first, and so Okazaki fragments are not needed. The lagging strand unwinds second resulting in the need to produce Okazaki fragments.

A) The two parental strands of DNA are antiparallel and DNA polymerase makes DNA in the 5' to 3' direction only.

35) During the DNA replication process, which of the following organisms would have the fewest origins of replication per cell? A) a Streptococcus bacterium B) a yeast cell C) a human D) a young oak tree E) a fruit fly

A) a Streptococcus bacterium

15) All of the following nucleotide bases are pyrimidines except A) adenine. B) thymine. C) cytosine. D) uracil. E) cytosine and thymine.

A) adenine.

19) Which purine base forms 3 hydrogen bonds when binding its complementary nucleotide base? A) guanine B) cytosine C) thymine D) uracil E) adenine

A) guanine