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MMSC 491 Exam 1 Questions with 100% Verified
Answers UPDATED!!!
With reference to aberrant methylation of bases which of the
following statements, if any, is false?
A. S-adenosylmethionine donates methyl groups to a range of
different molecules in cells and frequently inappropriately
methylates bases in DNA.
B. Guanine is occasionally methylated to give O-6-
methylguanine which base pairs with adenine rather than with
cytidine.
C. In each nucleated cell, about 300-600 adenines are converted
to 3-methyladenine per day.
D. 3-methyladenine can be a cytotoxic base: it distorts the
double helix and that can disrupt crucial DNA-protein
interactions. - ANSWER B
With reference to base cross-linking, which, if any, of the
following statements, is false?
A. Base cross-linking means that covalent bonds form between
two bases.
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B. The cross-linked bases are on opposing DNA strands.
C. The anti-cancer agent cisplatin causes a type of cross-linking
between two guanine residues.
D. Pyrimidine dimers are a type of base cross-linking that is
commonly induced by excess exposure to sunlight. - ANSWER B
Which, if any, of the following statements is false, regarding the
sources of genetic variation?
A. Most of the inherited changes in our DNA arise because of
exposure to extracellular mutagens, including radiation sources
and chemical mutagens.
B. Most of the inherited changes in our DNA arise because of
unavoidable endogenous errors in cellular mechanisms and
harmful effects of certain natural molecules and atoms within
our cells.
C. Errors in DNA replication and DNA repair are a major source
of mutations in our cells.
D. Significant chemical damage is sustained by DNA because of
its proximity to water molecules in our cells. - ANSWER A
Nucleic acid hybridization assays are normally carried out under
relaxed hybridization stringency (to maximize the chances of
heteroduplex formation) but afterwards, washes are carried out
that can be designed to favor perfectly matched sequences only
,3|Page
by changing some parameter. Which, if any, of the following
changes would be consistent with that aim?
a) An increase in temperature.
b) An increase in salt concentration.
c) An increase in the concentration of a polar molecule, such as
urea or formamide.
d) Both A and C
E) A, B, and C - ANSWER D
Which of the following statements, if any, is false?
A. PCR requires the use of a heat-stable DNA polymerase to
make copies of the template DNA.
B. PCR is usually used to amplify a specific DNA sequence of
interest using
C. Oligonucleotide primers that bind to closely flanking
sequences.
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D. PCR is superior to cell-based DNA cloning for two major
reasons: it is much quicker and it allows much greater DNA
amplification. - ANSWER D
For many of our genes, the initial RNA transcript needs to be
cleaved into pieces. Some of the pieces, called ____ ____, are
discarded, but other alternating pieces called ___ ____ are
retained and fused in the same linear order as their order when
transcribed. - ANSWER introns, exons
Which, if any, of the following statements are false?
a) Constitutive heterochromatin remains highly condensed
throughout the cell cycle.
b) Unlike constitutive heterochromatin, facultative
heterochromatin describes chromatin that
can de-condense and behave as euchromatin under certain
circumstances.
c) Most of the long arm of the Y chromatin is made up of
constitutive heterochromatin.
MMSC 491 Exam 1 Questions with 100% Verified
Answers UPDATED!!!
With reference to aberrant methylation of bases which of the
following statements, if any, is false?
A. S-adenosylmethionine donates methyl groups to a range of
different molecules in cells and frequently inappropriately
methylates bases in DNA.
B. Guanine is occasionally methylated to give O-6-
methylguanine which base pairs with adenine rather than with
cytidine.
C. In each nucleated cell, about 300-600 adenines are converted
to 3-methyladenine per day.
D. 3-methyladenine can be a cytotoxic base: it distorts the
double helix and that can disrupt crucial DNA-protein
interactions. - ANSWER B
With reference to base cross-linking, which, if any, of the
following statements, is false?
A. Base cross-linking means that covalent bonds form between
two bases.
,2|Page
B. The cross-linked bases are on opposing DNA strands.
C. The anti-cancer agent cisplatin causes a type of cross-linking
between two guanine residues.
D. Pyrimidine dimers are a type of base cross-linking that is
commonly induced by excess exposure to sunlight. - ANSWER B
Which, if any, of the following statements is false, regarding the
sources of genetic variation?
A. Most of the inherited changes in our DNA arise because of
exposure to extracellular mutagens, including radiation sources
and chemical mutagens.
B. Most of the inherited changes in our DNA arise because of
unavoidable endogenous errors in cellular mechanisms and
harmful effects of certain natural molecules and atoms within
our cells.
C. Errors in DNA replication and DNA repair are a major source
of mutations in our cells.
D. Significant chemical damage is sustained by DNA because of
its proximity to water molecules in our cells. - ANSWER A
Nucleic acid hybridization assays are normally carried out under
relaxed hybridization stringency (to maximize the chances of
heteroduplex formation) but afterwards, washes are carried out
that can be designed to favor perfectly matched sequences only
,3|Page
by changing some parameter. Which, if any, of the following
changes would be consistent with that aim?
a) An increase in temperature.
b) An increase in salt concentration.
c) An increase in the concentration of a polar molecule, such as
urea or formamide.
d) Both A and C
E) A, B, and C - ANSWER D
Which of the following statements, if any, is false?
A. PCR requires the use of a heat-stable DNA polymerase to
make copies of the template DNA.
B. PCR is usually used to amplify a specific DNA sequence of
interest using
C. Oligonucleotide primers that bind to closely flanking
sequences.
, 4|Page
D. PCR is superior to cell-based DNA cloning for two major
reasons: it is much quicker and it allows much greater DNA
amplification. - ANSWER D
For many of our genes, the initial RNA transcript needs to be
cleaved into pieces. Some of the pieces, called ____ ____, are
discarded, but other alternating pieces called ___ ____ are
retained and fused in the same linear order as their order when
transcribed. - ANSWER introns, exons
Which, if any, of the following statements are false?
a) Constitutive heterochromatin remains highly condensed
throughout the cell cycle.
b) Unlike constitutive heterochromatin, facultative
heterochromatin describes chromatin that
can de-condense and behave as euchromatin under certain
circumstances.
c) Most of the long arm of the Y chromatin is made up of
constitutive heterochromatin.
