Question

How are replication errors corrected?

Answer 1

Replication

1. The process of making a new strand of DNA from the parent strand is called replication.
2. Replication is done by the DNA polymerase enzyme.
3. Any errors occurring during replication have to be essentially corrected; otherwise, the integrity of the genome will be lost.
4. DNA polymerase has a 3'⇢5' exonuclease activity which takes part in proofreading and correcting replication errors.
5. DNA polymerase moves one nucleotide back and removes the incorrectly incorporated nucleotides by 3’→5’ exonuclease activity.
6. These replication errors are also repaired after replication by nucleotide excision repair (NER), base excision repair(BER), and mismatch repair (MMR) mechanisms.