BIO 392 Exam 4 Prep Verified Study Questions And
Answers With Latest Solutions
In the Meselson-Stahl experiment, if D N A had been replicated conservatively, after two rounds of replication,
there would be _____. ANS one old, heavy band and one new, light band
All known bacterial D N A polymerases _____. ANS have 5′ to 3′ polymerization activity
The role of the DnaA protein in bacterial D N A replication is to _____. ANS allow helicase to unwind the
double helix
What protein is functioning at the point marked with the large arrow? ANS DNA polymerase III
What enzyme will replace the R N A primers found in the newly synthesized strand? ANS DNA pol I
What activity provides D N A pol III the ability to proofread? ANS DNA pol III has 3′→5′ exonuclease
activity.
Is there any role for an R N A polymerase in D N A replication? ANS Yes, to generate primers.
What does the term "processivity" mean in the context of D N A replication? ANS that length of D N A
that is replicated by the core enzyme before it detaches from the template
Telomerase _____. ANS contains its own R N A template
Eukaryotic D N A replication is more complex than prokaryotic because all of these except: ANS there is a
single origin of replication
After ONE round of DNA replication in Meselson and Stahl's classic experiment, ________. ANS the
conservative model was conclusively proven to be an inaccurate model
DNA replication proceeds ________. ANS semiconservatively
,If DNA replication were fully conservative, how many intact parental double helices would have been detected
in Meselson and Stahl's experiment after three rounds of replication? ANS 1
The amount of DNA that is replicated from a single origin of replication is referred to as a(n) ________. ANS
replicon
The Meselson and Stahl's experiment provided conclusive evidence for the semiconservative replication of
DNA in E. coli . What pattern of bands would occur in a CsCl gradient for conservative replication? ANS
After one generation in the 14N, there would be two bands, one heavy and one light (no intermediate). After
the second generation in the 14N, there would also be two bands, one heavy and one light (no intermediate).
Identify what is meant by the term autoradiography. ANS Autoradiography is a technique that allows an
isotope to be detected within a cell.
Identify a classic experiment that used autoradiography to determine the replicative nature of DNA in
eukaryotes. ANS The Taylor, Woods, and Hughes (1957) experiment used 3H-thymidine.
In the Meselson-Stahl experiment, which mode of replication was eliminated based on data derived after one
generation of replication? ANS conservative
The data obtained from the Meselson-Stahl experiment after one generation of replication eliminated the
dispersive model of DNA replication. ANS False
Which enzyme catalyzes the addition of nucleotides to a growing DNA chain? ANS DNA polymerase
Which of the following statements about DNA replication is true? ANS Single-strand binding proteins
stabilize the open conformation of the unwound DNA.
The results of the Meselson-Stahl experiments relied on all of the following except _______. ANS the fact
that DNA is the genetic material
After observing the results of one round of replication, the scientists obtained results from a second round. The
purpose of one additional round of replication was to _______. ANS distinguish between semi-
conservative and dispersive replication
, Which of the following would result from a third round of replication using the methods of Meselson and
Stahl? ANS One light band and one intermediate band
DNA polymerase III adds nucleotides ________. ANS to the 3' end of the RNA primer
Which cluster of terms accurately reflects the nature of DNA replication in prokaryotes? ANS fixed point
of initiation, bidirectional, semiconservative
Which DNA polymerase is mainly responsible for genome replication in E. coli? ANS DNA polymerase
III
The protein responsible for the initial step in unwinding the DNA helix during replication of the bacterial
chromosome is coded for by the ________ gene. ANS dnaA
The discontinuous aspect of replication of DNA in vivo is caused by ________. ANS the 5′ to 3′ polarity
restriction
During DNA replication, ________ are 1000-2000 nucleotide long strands synthesized on the ________ strand
to maintain the ________ of replication. ANS Okazaki fragments; lagging; bidirectionality
Which activity of E. coli DNA polymerase I is responsible for proofreading the newly synthesized DNA? ANS
3' to 5'; exonuclease
As unwinding of the helix occurs during DNA replication, tension referred to as ________ is created ahead of
the replication fork. This tension is relieved by the action of ________. ANS supercoiling; DNA gyrase
Which of the following statements is true regarding Okazaki fragments? ANS They are short fragments of
DNA synthesized from RNA primers on the lagging strand.
The activity of ________ would be quickly undone in the absence of single-stranded binding protein. ANS
DNA helicase
Answers With Latest Solutions
In the Meselson-Stahl experiment, if D N A had been replicated conservatively, after two rounds of replication,
there would be _____. ANS one old, heavy band and one new, light band
All known bacterial D N A polymerases _____. ANS have 5′ to 3′ polymerization activity
The role of the DnaA protein in bacterial D N A replication is to _____. ANS allow helicase to unwind the
double helix
What protein is functioning at the point marked with the large arrow? ANS DNA polymerase III
What enzyme will replace the R N A primers found in the newly synthesized strand? ANS DNA pol I
What activity provides D N A pol III the ability to proofread? ANS DNA pol III has 3′→5′ exonuclease
activity.
Is there any role for an R N A polymerase in D N A replication? ANS Yes, to generate primers.
What does the term "processivity" mean in the context of D N A replication? ANS that length of D N A
that is replicated by the core enzyme before it detaches from the template
Telomerase _____. ANS contains its own R N A template
Eukaryotic D N A replication is more complex than prokaryotic because all of these except: ANS there is a
single origin of replication
After ONE round of DNA replication in Meselson and Stahl's classic experiment, ________. ANS the
conservative model was conclusively proven to be an inaccurate model
DNA replication proceeds ________. ANS semiconservatively
,If DNA replication were fully conservative, how many intact parental double helices would have been detected
in Meselson and Stahl's experiment after three rounds of replication? ANS 1
The amount of DNA that is replicated from a single origin of replication is referred to as a(n) ________. ANS
replicon
The Meselson and Stahl's experiment provided conclusive evidence for the semiconservative replication of
DNA in E. coli . What pattern of bands would occur in a CsCl gradient for conservative replication? ANS
After one generation in the 14N, there would be two bands, one heavy and one light (no intermediate). After
the second generation in the 14N, there would also be two bands, one heavy and one light (no intermediate).
Identify what is meant by the term autoradiography. ANS Autoradiography is a technique that allows an
isotope to be detected within a cell.
Identify a classic experiment that used autoradiography to determine the replicative nature of DNA in
eukaryotes. ANS The Taylor, Woods, and Hughes (1957) experiment used 3H-thymidine.
In the Meselson-Stahl experiment, which mode of replication was eliminated based on data derived after one
generation of replication? ANS conservative
The data obtained from the Meselson-Stahl experiment after one generation of replication eliminated the
dispersive model of DNA replication. ANS False
Which enzyme catalyzes the addition of nucleotides to a growing DNA chain? ANS DNA polymerase
Which of the following statements about DNA replication is true? ANS Single-strand binding proteins
stabilize the open conformation of the unwound DNA.
The results of the Meselson-Stahl experiments relied on all of the following except _______. ANS the fact
that DNA is the genetic material
After observing the results of one round of replication, the scientists obtained results from a second round. The
purpose of one additional round of replication was to _______. ANS distinguish between semi-
conservative and dispersive replication
, Which of the following would result from a third round of replication using the methods of Meselson and
Stahl? ANS One light band and one intermediate band
DNA polymerase III adds nucleotides ________. ANS to the 3' end of the RNA primer
Which cluster of terms accurately reflects the nature of DNA replication in prokaryotes? ANS fixed point
of initiation, bidirectional, semiconservative
Which DNA polymerase is mainly responsible for genome replication in E. coli? ANS DNA polymerase
III
The protein responsible for the initial step in unwinding the DNA helix during replication of the bacterial
chromosome is coded for by the ________ gene. ANS dnaA
The discontinuous aspect of replication of DNA in vivo is caused by ________. ANS the 5′ to 3′ polarity
restriction
During DNA replication, ________ are 1000-2000 nucleotide long strands synthesized on the ________ strand
to maintain the ________ of replication. ANS Okazaki fragments; lagging; bidirectionality
Which activity of E. coli DNA polymerase I is responsible for proofreading the newly synthesized DNA? ANS
3' to 5'; exonuclease
As unwinding of the helix occurs during DNA replication, tension referred to as ________ is created ahead of
the replication fork. This tension is relieved by the action of ________. ANS supercoiling; DNA gyrase
Which of the following statements is true regarding Okazaki fragments? ANS They are short fragments of
DNA synthesized from RNA primers on the lagging strand.
The activity of ________ would be quickly undone in the absence of single-stranded binding protein. ANS
DNA helicase
