Matthew Meselson and Franklin Stahl grew E.coli (doubling time is 20 min) in medium containing 15 NH 4 Cl for many generations Then the E.coli was transferred to medium containing 14 NH 4 Cl. After 40 minutes, the cells were harvested and DNA was extracted and subjected to cesium chloride density gradient centrifugation. The proportion of light and hybrid DNA densities will be

Question

Matthew Meselson and Franklin Stahl grew E.coli (doubling time is 20 min) in medium containing 15 NH 4 Cl for many generations Then the E.coli was transferred to medium containing 14 NH 4 Cl. After 40 minutes, the cells were harvested and DNA was extracted and subjected to cesium chloride density gradient centrifugation. The proportion of light and hybrid DNA densities will be (A) 50% light and 50% hybrid DNA (B) 100% light DNA (C) 100% hybrid DNA (D) 25% light and 75% hybrid DNA

Tardigrade Admin · Accepted Answer

Since, the DNA replication is semiconservative (i.e., one strand of the parent double helix is conserved in each new DNA molecule), the proportion of light and hybrid bands in the experiment would be 50 % light and 50 % hybrid DNA.

50% light and 50% hybrid DNA

100% light DNA

100% hybrid DNA

25% light and 75% hybrid DNA

Since, the DNA replication is semiconservative (i.e., one strand of the parent double helix is conserved in each new DNA molecule), the proportion of light and hybrid bands in the experiment would be 50% light and 50% hybrid DNA.

Since, the DNA replication is semiconservative (i.e., one strand of the parent double helix is conserved in each new DNA molecule), the proportion of light and hybrid bands in the experiment would be $50%$ light and $50%$ hybrid DNA.