THE MOLECULAR BASIS OF INHERITANCE
DNA REPLICATION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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the mismatch repair system
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DNA polymerase.
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excision repair.
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post-replication repair.
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Detailed explanation-1: -During proofreading, DNA polymerase enzymes recognize this and replace the incorrectly inserted nucleotide so that replication can continue. Proofreading fixes about 99% of these types of errors, but that’s still not good enough for normal cell functioning.
Detailed explanation-2: -Nucleotide excision-repair uses DNA polymerases delta or epsilon to resynthesize the bases removed during repair of pyrimidine dimers and other bulky adducts in DNA. Similarly, mismatch-repair of replication errors appears to involve DNA polymerases delta or epsilon.
Detailed explanation-3: -Most of the mistakes during DNA replication are promptly corrected by DNA polymerase by proofreading the base that has been just added (Figure 14.6.
Detailed explanation-4: -In addition to their roles in chromosomal DNA replication, DNA polymerases participate in numerous DNA repair pathways, including double-strand break repair (61–63), mismatch repair (3, 64, 65), base excision repair (3, 66, 67), and nucleotide excision repair (3).
Detailed explanation-5: -During DNA synthesis, most DNA polymerases “check their work, ” fixing the majority of mispaired bases in a process called proofreading. Immediately after DNA synthesis, any remaining mispaired bases can be detected and replaced in a process called mismatch repair.