DNA Sequencing, Mutation and Repair MCQs : This section focuses on the "DNA Sequencing, Mutation and Repair". These Multiple Choice Questions (MCQs) should be practiced to improve the DNA Sequencing, Mutation and Repair skills required for various interviews (campus interview, walk-in interview, company interview), placement, entrance exam and other competitive examinations.
Question 1
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
Question 2
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
Question 3
Which of the following mutations arise without exposure to external agents?
A. Spontaneous mutations
B. Analogous mutations
C. Induced mutations
D. None of these
Question 4
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
Question 5
Which of these mechanisms for thymine dimers repair lead to mutations?
A. Excision repair
B. Photoreactivation
C. SOS repair
D. Never leads to mutation
Question 6
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
Question 7
Genetic variations are
A. temporary
B. influenced by the environment
C. stable
D. not heritable
Question 8
Which of the following bacterial genome was sequenced first?
A. E. coli
B. S. pneumoniae
C. H. influenzae
D. S. thermophilus
Question 9
Changes in which of the following characterizes mutations?
A. Phenotype
B. Genotype
C. Both (a) and (b)
D. None of these
Question 10
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
Question 11
Which of the following(s) is/are steps in excision repair mechanisms?
A. Excision
B. Incision
C. Ligation
D. All of these
Question 12
Thymine dimers are directly repaired with the help of visible light by process known as
A. phosphorylation
B. excision repair
C. photosynthesis
D. photoreactivation
Question 13
The mutation which will not affect the length of a protein is,
A. nonsense mutation
B. missense mutation
C. frameshift mutation
D. All of the above
Question 14
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 these
Question 15
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
Question 16
Changes in which of the following characterizes mutations?
A. Phenotype
B. Genotype
C. Both A and B
D. None of these
Question 17
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
Question 18
Which of the following(s) is/are steps in excision repair mechanisms?
A. Excision
B. Incision
C. Ligation
D. All of the above
Question 19
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
Question 20
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
Question 21
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
Question 22
Which of the following mutation affects only a single nucleotide?
A. Aerial mutation
B. Site mutation
C. Point mutation
D. Regional mutation
Question 23
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
Question 24
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