Which strand is referred to as the parent strand in DNA replication?

In DNA replication, the parent strand is the original template strand from which new DNA is synthesized. During the process, the double helix unwinds, and each of the two separated strands serves as a template for the formation of new complementary strands.

The correct reference for the parent strand relates to its role in guiding the synthesis of the new strands. The original strands of the double helix remain intact and are used to direct the synthesis of complementary nucleotides. This means that the strand that serves as the template for the new strand should be considered the parent strand.

Regarding the other options:

• The new strand is formed as a result of replication and is therefore not the parent strand.
• Methylated strands refer to strands that have undergone methylation, which is a modification but does not directly define the parent strand in the context of replication.
• The leading strand is one of the new strands that is synthesized continuously in the direction of the replication fork but is not considered the original or parent strand.

Therefore, the parent strand is crucial in providing the sequence that determines the complementary base pairing necessary for the synthesis of new DNA during replication.