Question

Pick the statement about DNA repair that is true.

		Base excision repair removes bulky DNA lesions like thymidine dimers.
		Nucleotide excision repair is used immediately after replication to correct errors that escape proofreading.
		Direct repair directly changes modified bases back to their original structure.
		Mismatch repair reduces the fidelity of DNA polymerase.
		SOS repair uses DNA glycosylases to recognize and remove a specific type of modified base.

Answer 1

Ans:- Direct repair directly changes modified bases back to their original structure.

explanation:- direct repair mechanism is also called as direct damage reversal which involved in direct reversal of damaged nucleotide back to its original form in one step reaction. other options are not trues because base excision repairs is a mechanism which repair small damage and remove small base lesion in gene. nucleotide excision repair is mechanism which repair bulk DNA damage like thymidine dimer and not involved in proofreading. mismatch repair mechanism repair deletion, wrong insertion and mismatch of DNA. SOS repair mechanism does not use DNA glycosylase. DNA glycosylase used by base excision repair to initiate repair mechanism.