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DNA Repair Mechanism: MCQ with Answer Key by Easybiologyclass (Molecular Biology MCQ with Answer Key: MCQ 019)

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DNA Repair Mechanism MCQ with Answer Key:2015 Nobel Prize in Chemistry: Mechanistic Studies of DNA Repair: Molecular Biology Model Multiple Choice Questions for CSIR JRF NET Life Sciences, GATE XL and GATE BT Examination. by Easybiologyclass

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DNA Repair Mechanism: MCQ with Answer Key by Easybiologyclass (Molecular Biology MCQ with Answer Key: MCQ 019)

  1. 1. MCQ 019 Save paper… Save trees… For more Questions and Resources for your CSIR/ICMR/DBT/ICAR/UGC/JRF NET Life Science Examination please visit: www.easybiologyclass.com 1 Biology MCQ (Multiple Choice Questions in Life Science) (Sample/Model/Practice Questions for JRF/NET Life Science Examination, ICMR JRF, DBT JRF, GATE, ICAR NET, PG Entrance) Molecular Biology MCQ with Answer Key DNA Repair Mechanism (MCQ 019) 1. Which of the following DNA repair mechanism is known as the ‘cut and patch mechanism’? a. Photoreactivation b. Nucleotide excision repair c. Base excision repair d. Mismatch repair 2. DNA ligase enzyme involved in base excision repair mechanism is______. a. DNA helicase I b. DNA helicase II c. DNA helicase III d. DNA helicase IV 3. In mismatch repair mechanism, which of the following protein recognize DNA mismatches in the genomic DNA? a. MutH b. MutS c. MutL d. UvrD 4. The main difference between nucleotide excision repair (NER) and base excision repair (BER) is: a. In NER double strand breaks are repaired where as in BER single strand breaks repaired b. NER is a light dependent reaction whereas BER is light independent process c. In NER phosphodiester backbone is first cleaved where as in BER phosphodiester backbone is cleaved later d. All of these 5. Which enzyme is responsible for photoreactivation of DNA: a. Photoligase b. Photoreductase c. Photo‐oxidase d. Photolyase w w w .easybiologyclass.com
  2. 2. MCQ 019 Save paper… Save trees…   For more Questions and Resources for your CSIR/ICMR/DBT/ICAR/UGC/JRF NET Life Science Examination please visit: www.easybiologyclass.com 2   6. Which of the following enzyme(s) is involved base excision repair? a. DNA glycosylase b. AP endonuclease c. AP exonuclease d. (a), (b) and (c) e. Both (a) and (b) 7. Xeroderma pigmentosum in human is associated with a mutation in a. Photoreactivation b. Nucleotide excision repair c. Base excision repair d. Mismatch repair 8. Which of the following gene is NOT involved in mismatch repair system in bacteria? a. MutS b. MutA c. MutL d. UvrD 9. In eukaryotes, the mismatch repair mechanism is initiated and directed by_____. a. Methylated DNA strand b. Acetylated DNA strand c. Strand specific nicks d. Double strand breaks 10. In nucleotide excision repair mechanism which of the following proteins first recognize DNA lesion? a. UvrA b. UvrB c. UvrC d. UvrD 11. The two chromophores present in photolyase enzyme are: a. NAD and FAD b. FAD and Folate c. FADH and Folate – d. FAD – and Folate 12. Which of the following statement is true regarding the nucleotide excision repair (NER) mechanism? a. NER mechanism is present only in eukaryotes b. NER present only in prokaryotes c. NER Present in both prokaryotes and eukaryotes but the exact mechanisms varies w w w .easybiologyclass.com
  3. 3. MCQ 019 Save paper… Save trees…   For more Questions and Resources for your CSIR/ICMR/DBT/ICAR/UGC/JRF NET Life Science Examination please visit: www.easybiologyclass.com 3   d. NER Present in both prokaryotes and eukaryotes with similar molecular mechanism in both 13. Photolyase enzyme involved in the photoreactivation can remove ______. a. UV induced double strand breaks b. UV induced thymine dimers c. Mismatches in DNA d. Single strand breaks in DNA 14. DNA polymerase enzyme involved in base excision repair mechanism is ______. a. Pol‐α b. Pol‐β c. Pol‐γ d. Pol‐δ 15. DNA polymerase enzyme involved in mismatch repair system of E. coli is ______. a. DNA Pol‐I b. DNA Pol‐II c. DNA Pol‐III d. DNA Pol‐β 16. In NER machinery, which of the following protein processes the helicase activity? a. UvrA b. UvrB c. UvrC d. UvrD 17. The catalytic activity of photolyase enzyme in the bacterial cells is activated by _____. a. UV light b. IR light c. Visible light near blue region d. Visible light near red region 18. In NER (nucleotide excision repair) mechanism, the incision at the 3’ position of the lesion is done by______. a. Uvr A b. UvrB c. UvrC d. UvrD 19. In mismatch repair mechanism, the endonuclease activity which cut the nascent DNA strand is done by: a. MutH b. MutL c. MutS w w w .easybiologyclass.com
  4. 4. MCQ 019 Save paper… Save trees…   For more Questions and Resources for your CSIR/ICMR/DBT/ICAR/UGC/JRF NET Life Science Examination please visit: www.easybiologyclass.com 4   d. UvrD 20. The activity of AP endonuclease is involved in ________. a. Base excision repair b. Nucleotide excision repair c. Mismatch repair d. Double strand break repair 21. Which of the following statement is correct? a. Photoreactivation is absent in human b. Photoreactivation is present in all organism c. Photoreactivation present only in plants and animals d. Photoreactivation is present only in bacteria 22. The enzyme photolyase repair the thymine dimer in the DNA by __________ mechanism. a. Oxidation mechanism b. Free radical mechanism c. Direct bond breaking d. Adduct formation 23. In E. coli, inactivation of cellular DNA methylase enzyme causes severe mutation in the genomic DNA. Which of the following DNA repair mechanism would be most probably inhibited? a. Double strand break repair b. Mismatch repair c. Base Excision Repair d. Nucleotide Excision Repair 24. The function of UvrC in NER mechanism is_________. a. To identify the lesion in the DNA b. Helicase activity to unwind the DNA c. Catalyze the incision at the 3’ end of the lesion d. Catalyze the incision at the 5’ side of the lesion 25. First DNA glycosylase enzyme discovered is ___________. a. Uracil DNA glycosylase b. Thymine DNA glycosylase c. Adenine DNA glycosylase d. Methyl Adenine Glycosylase For correct answers and explanations please visit (http://www.easybiologyclass.com/biology‐mcq‐multiple‐choice‐questions/ w w w .easybiologyclass.com

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