Question

State whether the following statement is true or false.

Meselson and Stahl showed clearly that DNA replication was semiconservative.

Answer 1

This statement is true.

Explanation:

In their 1958 experiment, Meselson and Stahl grew E. coli in a medium containing a heavy nitrogen isotope (15N) and then switched them to a medium with a lighter isotope (14N). By using density gradient centrifugation to track the DNA, they observed that the “heavy” parental strands separated and each served as a template for a “light” new strand, resulting in hybrid DNA. This result provided definitive evidence for the semi-conservative model, proving that every new DNA molecule contains one original strand and one newly synthesised strand.