DNA Sequencing, Mutation and Repair
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Which
of the following mutations arise without exposure to external agents?
a.
Spontaneous mutations
b.
Analogous mutations
c.
Induced mutations
d. None
of these
Due
to which of the following DNA repair mechanisms, one is able to distinguish
newly synthesized DNA strands from older one?
a. New
strands do not contain cytosine bases
b. New
strands are lower in molecular size
c.
Old strands are methylated while new strands are not
d. New
strands are methylated while old strands are not
Changes
in which of the following characterizes mutations?
a.
Phenotype
b.
Genotype
c.
Both (a) and (b)
d. None
of these
Which
of the following(s) is/are steps in excision repair mechanisms?
a.
Excision
b.
Incision
c.
Ligation
d.
All of these
What
was the first eukaryotic chromosome to be sequenced?
a.
Yeast chromosome III
b.
Yeast chromosome XI
c.
Arabidopsis chromosome IV
d. None
of these
Genetic
variations are ___________.
a.
temporary
b.
influenced by the environment
c.
stable
d. not
heritable
The
mutation which will not affect the length of a protein is ___________.
a.
nonsense mutation
b.
missense mutation
c.
frameshift mutation
d. all
of these
Which
of the following bacterial genome was sequenced first?
a. E.
coli
b. S.
pneumoniae
c.
H. influenzae
d. S.
thermophilus
A
nonsense mutation may result into ___________.
a. an
abnormal elongation of a polypeptide
b. a
large deletion within the reading frame of a gene
c. a
premature termination of the synthesis of a polypeptide
d.
modification of mRNA
The
whole-genome shotgun sequencing approach depends primarily on ___________.
a.
rapidly sequencing thousands of small randomly cloned fragments
b.
methodical sequencing a few large cloned fragments of DNA
c.
sequencing the bacterial chromosome while it is still intact
d. all
of the above
Which
of the following mutation affects only a single nucleotide?
a.
Aerial mutation
b. Site
mutation
c.
Point mutation
d.
Regional mutation
A
mutagen is defined as ___________.
a. an
enzyme that repairs mutations
b. a
chemical or physical agent that induces mutations
c. an
inhibitor of gene modification
d. a
molecule which stabilizes DNA thus prevents mutations from occurring
The
DNA sequences of rRNA genes can be used to ___________.
a.
assess relatedness of eukaryotes but not prokaryotes
b.
obtain a tentative identification of a new microorganism
c.
predict the pulsed field gel pattern of a microorganism
d.
predict whether a bacteria will be gram-positive or gram-negative
The
promoter on an expression vector used to overproduce proteins in bacteria is
___________.
a. a
bacterial promoter
b.
expressed both in bacteria and mammalian cells
c. not
a regulated promoter
d. the
natural promoter of the gene being cloned
Frame
shift mutation may occur as a result of ___________.
a.
formation of a thymine-dimer
b.
deamination of cytosine to uracil
c.
conversion of guanine to xanthine
d.
none of the above
A
nonsense mutation introduced into the DNA sequence of a gene may ___________.
a.
cause premature termination of the mRNA
b.
shorten the length of the protein encoded by the gene
c. have
no effect on the transcript or protein made
d.
cause a shift in reading frame
Differentiation
of four different bases in automated sequencing systems is that each base has
___________.
a.
different radioactive tag
b.
cytosine at start
c.
unique antibody bound to it
d.
distinctive fluorescent tag
When
mutations involve vital functions so that the mutants are nonviable, it is a
___________.
a.
nonsense mutation
b.
lethal mutation
c.
transversion
d. none
of these
Which
of these mechanisms for thymine dimers repair lead to mutations?
a.
Excision repair
b.
Photoreactivation
c.
SOS repair
d.
Never leads to mutation
Thymine
dimers are directly repaired with the help of visible light by process known as
___________.
a.
phosphorylation
b.
excision repair
c.
photosynthesis
d.
photoreactivation