The bacterial repair system that corrects mismatched bases after polymerization is able to discriminate between the old and newly made DNA strands because
A)the new strand will contain the incorrect base if a mismatch occurs.
B)older DNA is more likely to contain errors.
C)older DNA contains methyl groups at specific sequences
D)newer DNA contains methyl groups at specific sequences
E)the DNA polymerase is attached to the new strand

Question

Quizplus · Accepted Answer

The bacterial repair system is able to discriminate between the old and newly made DNA strands because older DNA contains methyl groups at specific sequences. These methyl groups indicate that the old strand is the template strand and should be used as the correct reference for base pairing. The repair system can identify and correct any mismatches that occur on the newly synthesized strand.

The Bacterial Repair System That Corrects Mismatched Bases After Polymerization