DNA Replication
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In
E.coli, which enzyme synthesizes the RNA primer for Okazaki fragments?
a. DnaA
b. DnaC
c.
DnaG
d. all
of these
During
which of the following process a new copy of a DNA molecule is precisely
synthesized?
a.
Trasformation
b.
Transcription
c. Translation
d.
Replication
Which
of the following repairs nicked DNA by forming a phosphodiester bond between
adjacent nucleotides?
a.
Helicase
b. DNA
gyrase
c.
Topoisomerases
d.
DNA ligase
The
enzyme that catalyzes the synthesis of DNA is called ___________.
a.
DNA polymerase
b. DNA
gyrase
c. DNA
ligase
d.
helicase
The
replication of chromosomes by eukaryotes occurs in a relatively short period of
time because ___________.
a. the
eukaryotes have more amount of DNA for replication
b. the
eukaryotic replication machinery is 1000 times faster than the prokaryotes
c.
each chromosome contains multiple replicons
d.
eukaryotic DNA is always single stranded
Both
strands of DNA serve as templates concurrently in ___________.
a.
replication
b.
excision repair
c.
mismatch repair
d. none
of these
Proofreading
activity to maintain the fidelity of DNA synthesis ___________.
a.
occurs after the synthesis has been completed
b.
is a function of the 3'-5' exonuclease activity of the DNA polymerases
c.
requires the presence of an enzyme separate from the DNA polymerases
d.
occurs in prokaryotes but not eukaryotes
DNA
gyrase is inhibited by ___________.
a.
tetracycline
b.
nalidixic acid
c. both
(a) and (b)
d.
cephalosporin
Which
of the following enzymes unwind short stretches of DNA helix immediately ahead
of a replication fork?
a. DNA
polymerases
b.
Helicases
c.
Single-stranded binding proteins
d.
Topoisomerases
Which
of the following possesses both 5'-3' and 3'-5' exonuclease activity?
a.
Kornberg enzyme
b. DNA
polymerase III
c. Taq
DNA polymerase
d. None
of these
Which
of the following statements on replication in E.coli is correct?
a. It
occurs in a unidirectional manner
b.
It occurs in bidirectional manner
c.
Always uses T7 DNA polymerase when infected by T7 phage
d.
Occurs only when λ phase has infected E. coli
During
DNA replication in prokaryotes, synthesis begins on the circular chromosome ___________.
a.
always at the same place
b. at
any stretch of DNA that is high in AT pairs
c.
randomly on the chromosome
d. at
the promoter
DNA
replication rates in prokaryotes are approximately of the order of ___________.
a. 10
bases per second
b. 1,00
bases per second
c.
1,000 bases per second
d.
10,000 bases per second
Which
of the following lacks 3'-5' exonuclease activity?
a.
Short fragment of DNA polymerase I
b. Taq
DNA polymerase
c. T4
DNA ligase
d.
All of the above
The
synthesis of DNA by DNA polymerase occurs in the ___________.
a. 3'
to 5' direction
b. 5'
to 5' direction
c.
5' to 3' direction
d. 3'
to 3' direction