1. Tardigrade
  2. Question
  3. Biology
  4. 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 Error Report

Thank you for reporting, we will resolve it shortly

Back to Question

Q. 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

KVPYKVPY 2017

Solution:

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.