Sometimes proofreading fails and an incorrect base is inserted in the new DNA.

gggattcgtat tagcact ccctaagcatAAtaCgTAtcgtGa

^ Mismatch repair enzymes recognize the deformity in secondary structure caused by the mismatched base.


■ ccctaagcaTAatccgTatcgtGÂI

gggattcgtat a

.and replace the mismatched base with the correct one.

Conclusion: Multiple mechanisms ensure highly accurate DNA replication.

12.16 A series of processes are required to ensure the incredible accuracy of DNA replication. Among these processes are DNA selection, proofreading, and mismatch repair.

6. Replication is continuous on the leading strand and discontinuous on the lagging strand.

7. New nucleotide strands are made complementary and antiparallel to their template strands.

8. Replication takes place at very high rates and is astonishingly accurate, thanks to precise nucleotide selection, proofreading, and repair mechanisms.

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