Engineering Questions with Answers - Multiple Choice Questions

MCQs on DNA Repair

1 - Question

The correction of changes in DNA by a set of process known as___________
a) Replication
b) DNA repair
c) Translation
d) Transcription

View Answer

Answer: b
Explanation: DNA repair is the correction process which is used to maintain genetic stability.




2 - Question

The genome can maintain its essential cellular function even without DNA repair.
a) True
b) False

View Answer

Answer: b
Explanation: Genome cannot maintain its essential cellular function if the DNA is damaged. So, for the accurate functioning, a set of correction processes are used known as DNA repair.




3 - Question

Name the repair system for UV mediated damage of DNA?
a) Exchange of homologous segments
b) DNA glycosylase
c) Nucleotide excision repair
d) Photoreactivation

View Answer

Answer: d
Explanation: Exposure to UV radiation can cause pyrimidine dimer which is repaired by a light dependent direct system called photoreactivation.




4 - Question

Which of the following enzyme is used in photoreactivation process?
a) DNA ligase
b) DNA photolyase
c) DNA polymerase
d) Primase

View Answer

Answer: b
Explanation: DNA photolyase participates in the DNA repair system when the damage takes place by UV radiation.




5 - Question

Name the repair system which involves the removal of the damaged segment of DNA?
a) Recombinational repair
b) Direct repair
c) Excision repair
d) Mismatched repair

View Answer

Answer: c
Explanation: Excision of the damaged site comes under the excision repair system. It is of two types, base excision repair and nucleotide excision repair.




6 - Question

Name the enzyme which initiates base excision repair process?
a) RNA polymerase
b) DNA polymerase
c) DNA photolyase
d) DNA glycosylase

View Answer

Answer: d
Explanation: DNA glycosylase cleaves N-glycosidic bonds which liberates altered base and generates apurinic or an apyrimidic site.




7 - Question

Which of the following enzyme works in the nucleotide excision repair?
a) DNA photolyase
b) ABC exinuclease
c) DNA glycosylase
d) RecA

View Answer

Answer: b
Explanation: ABC excinuclease involves the removal of short, usually 12 nucleotide segment. This system is best studied in E.coli.




8 - Question

Mark the one, which is NOT a subunit of ABC exinuclease?
a) UvrA
b) UvrB
c) UvrC
d) UvrF

View Answer

Answer: d
Explanation: ABC exinuclease binds at the site of lesion for the purpose of excision. It consists of three subunits i.e, UvrA, UvrB, and UvrC.




9 - Question

. Which of the following is NOT the function of the enzyme systems involved in mismatch repair?
a) Recognize mismatched base pair
b) Gene conversion
c) Determine incorrect base from a mismatch
d) Excise incorrect base and carry out repair system

View Answer

Answer: b
Explanation: Gene conversion is the phenomenon of changing allele forms during recombination and DNA repair.




10 - Question

Mark the one, which is CORRECT for SOS repair.
a) RecA protein participates
b) A free radical mechanism is involved
c) The repair enzyme functions only once
d) No bases or nucleotides are removed

View Answer

Answer: a
Explanation: SOS repair involves RecA protein and is responsible for error prone replication. Final reaction is catalyzed by DNA ligase.

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