Question

DNA replicates semiconservatively was first shown in:

• A. Higher animals
• B. Esherichiacoil
• C. Human cell
• D. Plants

Answer 1

The Correct Option is B

The concept of semiconservative DNA replication was first demonstrated by the scientists Matthew Meselson and Franklin Stahl in 1958 using Escherichia coli (E. coli) bacteria. They conducted an elegant experiment known as the Meselson-Stahl experiment to investigate how DNA is replicated.

In their experiment, Meselson and Stahl labeled the DNA of E. coli bacteria with a heavy isotope of nitrogen (15N) by growing the bacteria in a medium containing this isotope. They then transferred the labeled bacteria to a medium containing a lighter isotope of nitrogen (14N) and allowed them to replicate their DNA.

Answer 2

The experiment that definitively demonstrated that DNA replicates semi-conservatively was performed using Escherichia coli (E. coli).

This groundbreaking experiment was conducted by Matthew Meselson and Franklin Stahl in 1958. They used isotopes of nitrogen to label the DNA of *E. coli* and then tracked the distribution of the labeled DNA during replication. Their results provided clear evidence that each new DNA molecule consists of one original (parental) strand and one newly synthesized strand, confirming the semi-conservative model of replication.