Test Bank: Concepts of Genetics, 3rd Edition by Brooker ,
Chapters 1-24, 9781259879906 | Rationals Included
Which of the three models of DNA replication proposed that the original double helix remained
entirely intact throughout the process?
A) Conservative model.
B) Semiconservative model.
C) Dispersive model.
D) Destructive model.
E) None of these. - ANSWER:Conservative model
Which statement about bacterial DNA replication is correct?
A) DNA replication begins at several places along the chromosome.
B) DNA replication begins at the origin and travels in both directions.
C) DNA replication begins at the origin and travels around the chromosome back to the origin.
D) DNA replication begins at a GC rich region of the chromosome.
E) All of these are correct. - ANSWER:DNA replication begins at the origin and travels in both
directions.
Why is an AT rich region part of the E. coli oriC?
A) DnaA proteins bind to AT rich sites.
B) DnaC proteins bind to AT rich sites.
C) AT base pairs are more easily separated than GC base pairs.
D) AT base pairs contain more hydrogen bonds than GC base pairs. - ANSWER:AT base pairs are more
easily separated than GC base pairs.
Which enzyme produces the first piece of nucleic acid synthesized in E. coli DNA replication?
A) DNA primase
B) DNA polymerase (polIII)
C) DNA polymerase (polI)
D) DNA ligase - ANSWER:DNA primase
What is a key difference between DNA polIII and DNA ligase?
A) Only DNA polIII synthesizes phosphoester bonds.
B) Only DNA ligase synthesizes phosphoester bonds.
C) DNA polIII can synthesize DNA from 3'-5'.
D) DNA ligase can use energy from ATP rather than nucleotides. - ANSWER:DNA ligase can use energy
from ATP rather than nucleotides.
What is the major difference between the lagging and leading strands?
A) On the leading strand, DNA synthesis occurs from 5' to 3', while DNA synthesis occurs from 3' to 5'
on the lagging strand.
B) DNA polymerase is able to continuously add new nucleotides on the leading strand while it must
keep 'starting over' on the lagging strand.
C) The lagging strand requires only a single primer while the leading strand requires many.
D) Helicase opens the leading strand at a faster rate than the lagging strand. - ANSWER:DNA
polymerase is able to continuously add new nucleotides on the leading strand while it must keep
'starting over' on the lagging strand.
What explanation for Okazaki fragments is the most accurate?
A) DNA polymerase is only able to synthesize 1000-2000 bonds before it falls off the strand.
B) DNA polymerase must stop to check its work every 1000-2000 nucleotides.
C) DNA polymerase requires a free 3' OH group to attach new nucleotides; primers are produced on
the lagging strand every 1000-2000 nucleotides.
, D) All of these are accurate statements.
E) None of these are accurate statements. - ANSWER:DNA polymerase requires a free 3' OH group to
attach new nucleotides; primers are produced on the lagging strand every 1000-2000 nucleotides.
What DNA sequence is required for termination of replication in E. coli?
A) oriC
B) ter
C) Tus
D) Fork - ANSWER:ter
What is the major difference between T1 and T2 ter sequences?
A) Tus binds to T1 but not T2.
B) Tus binds to T2 but not T1.
C) T1 stops only counterclockwise-moving forks while T2 stops only clockwise-moving forks.
D) T2 stops only counterclockwise-moving forks while T1 stops only clockwise-moving forks. -
ANSWER:T1 stops only counterclockwise-moving forks while T2 stops only clockwise-moving forks.
What enzyme performs decatenation?
A) Polymerase.
B) Topoisomerase.
C) Telomerase.
D) Decatenase. - ANSWER:Topoisomerase.
Which is a correct description of the replisome?
A) The replisome is a complex of several proteins.
B) The replisome includes DNA polymerase, DNA helicase, and primase.
C) The replisome can be found at the replication fork during DNA synthesis.
D) All of these are correct descriptions.
E) None of the above are correct. - ANSWER:All of these are correct descriptions.
Which of the following is a description of the proofreading function of DNA polymerase?
A) Endonuclease cleavage.
B) Exonuclease cleavage.
C) Methylation.
D) An induced-fit phenomenon.
E) All of these. - ANSWER:Exonuclease cleavage
Which of the following is not a mechanism by which E. coli can coordinate DNA replication with cell
division?
A) DnaA protein does not efficiently bind to hemimethylated binding sites in the oriC.
B) DNA polymerase does not efficiently bind to mismatched base pairs.
C) DnaA protein is rapidly degraded after the initiation of DNA replication.
D) DnaA proteins must bind to a minimum number of binding sites in the oriC.
E) None of these; all are such mechanisms. - ANSWER:DNA polymerase does not efficiently bind to
mismatched base pairs.
Which of the following is a key difference between eukaryotic and prokaryotic DNA replication?
A) Eukaryotic origins of replication contain a high % of AT base pairs and require protein binding for
correct function.
B) In eukaryotes, DNA replication proceeds bidirectionally from the origin of replication.
C) Eukaryotes contain several different DNA polymerases.
D) Telomerase is required to replicate the ends of eukaryotic chromosomes.
E) None of these: They could all also describe prokaryotic DNA replication. - ANSWER:Telomerase is
required to replicate the ends of eukaryotic chromosomes.
What aspect of DNA polymerase function necessitates use of telomerase in eukaryotes?
A) 3'-5' exonuclease function.
Chapters 1-24, 9781259879906 | Rationals Included
Which of the three models of DNA replication proposed that the original double helix remained
entirely intact throughout the process?
A) Conservative model.
B) Semiconservative model.
C) Dispersive model.
D) Destructive model.
E) None of these. - ANSWER:Conservative model
Which statement about bacterial DNA replication is correct?
A) DNA replication begins at several places along the chromosome.
B) DNA replication begins at the origin and travels in both directions.
C) DNA replication begins at the origin and travels around the chromosome back to the origin.
D) DNA replication begins at a GC rich region of the chromosome.
E) All of these are correct. - ANSWER:DNA replication begins at the origin and travels in both
directions.
Why is an AT rich region part of the E. coli oriC?
A) DnaA proteins bind to AT rich sites.
B) DnaC proteins bind to AT rich sites.
C) AT base pairs are more easily separated than GC base pairs.
D) AT base pairs contain more hydrogen bonds than GC base pairs. - ANSWER:AT base pairs are more
easily separated than GC base pairs.
Which enzyme produces the first piece of nucleic acid synthesized in E. coli DNA replication?
A) DNA primase
B) DNA polymerase (polIII)
C) DNA polymerase (polI)
D) DNA ligase - ANSWER:DNA primase
What is a key difference between DNA polIII and DNA ligase?
A) Only DNA polIII synthesizes phosphoester bonds.
B) Only DNA ligase synthesizes phosphoester bonds.
C) DNA polIII can synthesize DNA from 3'-5'.
D) DNA ligase can use energy from ATP rather than nucleotides. - ANSWER:DNA ligase can use energy
from ATP rather than nucleotides.
What is the major difference between the lagging and leading strands?
A) On the leading strand, DNA synthesis occurs from 5' to 3', while DNA synthesis occurs from 3' to 5'
on the lagging strand.
B) DNA polymerase is able to continuously add new nucleotides on the leading strand while it must
keep 'starting over' on the lagging strand.
C) The lagging strand requires only a single primer while the leading strand requires many.
D) Helicase opens the leading strand at a faster rate than the lagging strand. - ANSWER:DNA
polymerase is able to continuously add new nucleotides on the leading strand while it must keep
'starting over' on the lagging strand.
What explanation for Okazaki fragments is the most accurate?
A) DNA polymerase is only able to synthesize 1000-2000 bonds before it falls off the strand.
B) DNA polymerase must stop to check its work every 1000-2000 nucleotides.
C) DNA polymerase requires a free 3' OH group to attach new nucleotides; primers are produced on
the lagging strand every 1000-2000 nucleotides.
, D) All of these are accurate statements.
E) None of these are accurate statements. - ANSWER:DNA polymerase requires a free 3' OH group to
attach new nucleotides; primers are produced on the lagging strand every 1000-2000 nucleotides.
What DNA sequence is required for termination of replication in E. coli?
A) oriC
B) ter
C) Tus
D) Fork - ANSWER:ter
What is the major difference between T1 and T2 ter sequences?
A) Tus binds to T1 but not T2.
B) Tus binds to T2 but not T1.
C) T1 stops only counterclockwise-moving forks while T2 stops only clockwise-moving forks.
D) T2 stops only counterclockwise-moving forks while T1 stops only clockwise-moving forks. -
ANSWER:T1 stops only counterclockwise-moving forks while T2 stops only clockwise-moving forks.
What enzyme performs decatenation?
A) Polymerase.
B) Topoisomerase.
C) Telomerase.
D) Decatenase. - ANSWER:Topoisomerase.
Which is a correct description of the replisome?
A) The replisome is a complex of several proteins.
B) The replisome includes DNA polymerase, DNA helicase, and primase.
C) The replisome can be found at the replication fork during DNA synthesis.
D) All of these are correct descriptions.
E) None of the above are correct. - ANSWER:All of these are correct descriptions.
Which of the following is a description of the proofreading function of DNA polymerase?
A) Endonuclease cleavage.
B) Exonuclease cleavage.
C) Methylation.
D) An induced-fit phenomenon.
E) All of these. - ANSWER:Exonuclease cleavage
Which of the following is not a mechanism by which E. coli can coordinate DNA replication with cell
division?
A) DnaA protein does not efficiently bind to hemimethylated binding sites in the oriC.
B) DNA polymerase does not efficiently bind to mismatched base pairs.
C) DnaA protein is rapidly degraded after the initiation of DNA replication.
D) DnaA proteins must bind to a minimum number of binding sites in the oriC.
E) None of these; all are such mechanisms. - ANSWER:DNA polymerase does not efficiently bind to
mismatched base pairs.
Which of the following is a key difference between eukaryotic and prokaryotic DNA replication?
A) Eukaryotic origins of replication contain a high % of AT base pairs and require protein binding for
correct function.
B) In eukaryotes, DNA replication proceeds bidirectionally from the origin of replication.
C) Eukaryotes contain several different DNA polymerases.
D) Telomerase is required to replicate the ends of eukaryotic chromosomes.
E) None of these: They could all also describe prokaryotic DNA replication. - ANSWER:Telomerase is
required to replicate the ends of eukaryotic chromosomes.
What aspect of DNA polymerase function necessitates use of telomerase in eukaryotes?
A) 3'-5' exonuclease function.
