Intro to Molecular Cell Biology Test Bank
Chapter 6
The process of DNA replication requires that each of the parental DNA strands be used as a
____________ to produce a duplicate of the opposing strand.
(a) catalyst
(b) competitor
(c) template
(d) copy - ANS (c) template
DNA replication is considered semiconservative because
__________________________________.
(a) after many rounds of DNA replication, the original DNA double helix is still intact.
(b) each daughter DNA molecule consists of two new strands copied form the parent
(c) each daughter DNA molecule consists of one strand from the parent DNA molecule and one
new strand. - ANS (c) each daughter DNA molecule consists of one strand from the parent
DNA molecule and one new strand
The classic experiment conducted by Meselson and Stahl demonstrated that DNA replication is
accomplished by employing a ______________ mechanism. - ANS semiconservative
Initiator proteins bind to replication origins and disrupt hydrogen bonds between the two DNA
strands being copied. Which of the factors below does not contribute to the relative ease of
strand separation by initiator proteins?
(a) replication origins are rich in A-T base pairs
(b) the reaction can occur at room temperature
(c) they only separate a few base pairs at a time
(d) once opened, other portions of the DNA replication machinery bind to the origin - ANS (b)
the reaction can occur at room temperature
If the genome of the bacterium E. coli requires about 20 minutes to replicate itself, how can the
genome of a fruit fly be replicated in only 3 minutes?
(a) The fruit fly genome is smaller than E coli
(b) Eukaryotic DNA polymerase synthesizes DNA at a much faster rate than prokaryotic
(c) The nuclear membrane keeps the fruit fly DNA concentrated in one place in the cell, which
increases the rate of polymerization
(d) Fruit fly DNA contains more origins of replication than E coli DNA. - ANS (d) Fruit fly DNA
contains more origins of replication than E coli DNA
, True or false?
When DNA is being replicated inside a cell, local heating occurs, allowing the two strands to
separate. - ANS False. This is accomplished by initiated proteins binding at the origin of
replication.
True or false?
DNA replication origins are typically rich in G-C base pairs. - ANS They are rich in A-T base
pairs which makes it easier for them to separate the strands because they are only held
together by two hydrogen bonds
True or false?
Meselson and Stahl ruled out the dispersive model for DNA replication. - ANS true
True or false?
DNA replication is a bidirectional process that is initiated at multiple locations among
chromosomes in eukaryotic cells. - ANS True
How many replication forks are formed when an origin of replication is opened? - ANS 2
How does the total number of replication origins in bacterial cells compare with the number of
origins in human cells? - ANS 1 versus 10,000
Which of the following statement correctly explains what it means for DNA replication to be
bidirectional?
(a) The replication forks formed at the origin moved in opposite directions.
(b) the DNA replication machinery can move in either direction on the template strand
(c) The replication fork can either open or close depending on the condition
(d) Replication form movement can switch directions when the fork converges on another
replication fork. - ANS (a) The replication forks formed at the origin move in opposite directions.
The chromatin structure in eukaryotic cells is much more complicated than that observed in
prokaryotic cells. This is thought to be the reason that DNA replication occurs much faster in
prokaryotes. How much faster is it?
(a) 2x
(b) 5x
(c) 10x - ANS (c) 10x
DNA polymerase catalyzes the joining of a nucleotide to a growing DNA strands. What prevents
this enzyme from catalyzing the reverse reaction?
(a) hydrolysis of pyrophosphate (PPi) to inorganic phosphate (Pi)+Pi
(b) release of PPi from the nucleotide
(c) hybridization of the new strand to the template
(d) loss of ATP - ANS (a) hydrolysis of pyrophosphate (PPi) to inorganic phosphate (Pi)+Pi
Chapter 6
The process of DNA replication requires that each of the parental DNA strands be used as a
____________ to produce a duplicate of the opposing strand.
(a) catalyst
(b) competitor
(c) template
(d) copy - ANS (c) template
DNA replication is considered semiconservative because
__________________________________.
(a) after many rounds of DNA replication, the original DNA double helix is still intact.
(b) each daughter DNA molecule consists of two new strands copied form the parent
(c) each daughter DNA molecule consists of one strand from the parent DNA molecule and one
new strand. - ANS (c) each daughter DNA molecule consists of one strand from the parent
DNA molecule and one new strand
The classic experiment conducted by Meselson and Stahl demonstrated that DNA replication is
accomplished by employing a ______________ mechanism. - ANS semiconservative
Initiator proteins bind to replication origins and disrupt hydrogen bonds between the two DNA
strands being copied. Which of the factors below does not contribute to the relative ease of
strand separation by initiator proteins?
(a) replication origins are rich in A-T base pairs
(b) the reaction can occur at room temperature
(c) they only separate a few base pairs at a time
(d) once opened, other portions of the DNA replication machinery bind to the origin - ANS (b)
the reaction can occur at room temperature
If the genome of the bacterium E. coli requires about 20 minutes to replicate itself, how can the
genome of a fruit fly be replicated in only 3 minutes?
(a) The fruit fly genome is smaller than E coli
(b) Eukaryotic DNA polymerase synthesizes DNA at a much faster rate than prokaryotic
(c) The nuclear membrane keeps the fruit fly DNA concentrated in one place in the cell, which
increases the rate of polymerization
(d) Fruit fly DNA contains more origins of replication than E coli DNA. - ANS (d) Fruit fly DNA
contains more origins of replication than E coli DNA
, True or false?
When DNA is being replicated inside a cell, local heating occurs, allowing the two strands to
separate. - ANS False. This is accomplished by initiated proteins binding at the origin of
replication.
True or false?
DNA replication origins are typically rich in G-C base pairs. - ANS They are rich in A-T base
pairs which makes it easier for them to separate the strands because they are only held
together by two hydrogen bonds
True or false?
Meselson and Stahl ruled out the dispersive model for DNA replication. - ANS true
True or false?
DNA replication is a bidirectional process that is initiated at multiple locations among
chromosomes in eukaryotic cells. - ANS True
How many replication forks are formed when an origin of replication is opened? - ANS 2
How does the total number of replication origins in bacterial cells compare with the number of
origins in human cells? - ANS 1 versus 10,000
Which of the following statement correctly explains what it means for DNA replication to be
bidirectional?
(a) The replication forks formed at the origin moved in opposite directions.
(b) the DNA replication machinery can move in either direction on the template strand
(c) The replication fork can either open or close depending on the condition
(d) Replication form movement can switch directions when the fork converges on another
replication fork. - ANS (a) The replication forks formed at the origin move in opposite directions.
The chromatin structure in eukaryotic cells is much more complicated than that observed in
prokaryotic cells. This is thought to be the reason that DNA replication occurs much faster in
prokaryotes. How much faster is it?
(a) 2x
(b) 5x
(c) 10x - ANS (c) 10x
DNA polymerase catalyzes the joining of a nucleotide to a growing DNA strands. What prevents
this enzyme from catalyzing the reverse reaction?
(a) hydrolysis of pyrophosphate (PPi) to inorganic phosphate (Pi)+Pi
(b) release of PPi from the nucleotide
(c) hybridization of the new strand to the template
(d) loss of ATP - ANS (a) hydrolysis of pyrophosphate (PPi) to inorganic phosphate (Pi)+Pi
