Q.69 Match the enzymes given in Group I with the events from Group II.
Group I
(P) UvrABC endonuclease
(Q) Reverse transcriptase
(R) AP endonuclease
(S) ATP sulfurylase
Group II
(I) Retrovirus replication
(II) Base excision repair
(III) Nucleotide excision repair
(IV) Pyrosequencing
(A) P-II, Q-I, R-IV, S-III
(B) P-III, Q-I, R-II, S-IV
(C) P-IV, Q-III, R-I, S-II
(D) P-II, Q-I, R-III, S-IV
Correct answer: (B) P-III, Q-I, R-II, S-IV
This matching question tests knowledge of key enzymes in DNA repair, replication, and sequencing, common in exams like CSIR NET or GATE Biotechnology.
Enzyme Functions
UvrABC endonuclease (P) performs nucleotide excision repair (NER) by detecting and excising bulky DNA lesions like UV-induced thymine dimers in bacteria.
Reverse transcriptase (Q) synthesizes DNA from viral RNA, essential for retrovirus replication such as HIV.
AP endonuclease (R) cleaves DNA at apurinic/apyrimidinic (AP) sites during base excision repair (BER) to remove damaged bases.
ATP sulfurylase (S) converts pyrophosphate to sulfate in pyrosequencing, enabling real-time DNA sequencing by chemiluminescence detection.
Options Explained
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(A) P-II, Q-I, R-IV, S-III: Wrong. P mismatches with BER (II); UvrABC is for NER (III). R mismatches with pyrosequencing (IV); AP endonuclease fits BER (II).
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(B) P-III, Q-I, R-II, S-IV: Correct. Matches exactly: P-NER (III), Q-retrovirus (I), R-BER (II), S-pyrosequencing (IV).
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(C) P-IV, Q-III, R-I, S-II: Wrong. P mismatches with pyrosequencing (IV); belongs to NER (III). Q mismatches with NER (III); specific to retroviruses (I).
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(D) P-II, Q-I, R-III, S-IV: Wrong. P mismatches with BER (II); for NER (III). R mismatches with NER (III); for BER (II).
Exam Preparation Tips
Understand repair pathways: NER (UvrABC) for helix-distorting damage, BER (AP endonuclease) for base modifications.
Retroviruses rely on reverse transcriptase for life cycle; pyrosequencing uses ATP sulfurylase for PPi detection in next-gen sequencing.
Practice similar MCQs from Testbook or PubMed for CSIR/NEET PG biotech sections.
