Exemplar Problems

Question:

Which property of DNA double helix led Watson and Crick to hypothesize the semi-conservative mode of DNA replication? Explain.

Answer:

The property of DNA double helix that led Watson and Crick to hypothesize the semi-conservative mode of DNA replication is the complementary base pairing.

In the DNA double helix, adenine (A) always pairs with thymine (T), and cytosine (C) always pairs with guanine (G). These base pairs are complementary, meaning that the sequence of one strand determines the sequence of the other.

In semi-conservative replication, each strand of the original DNA molecule serves as a template for the synthesis of a new complementary strand. This ensures that the genetic information is conserved, with one old strand and one newly synthesized strand in each daughter DNA molecule.

The complementary base pairing and the idea that each strand can serve as a template for replication supported the semi-conservative mode proposed by Watson and Crick.