Meselson and Stahl set out to demonstrate that replication in E. coli takes plac
ID: 171966 • Letter: M
Question
Meselson and Stahl set out to demonstrate that replication in E. coli takes place in a semiconservative manner. They first grew cells in a medium containing the heavy isotope of 15N for several generations. Then they switched the cells to a medium containing common nitrogen (14N). Using equilibrium centrifugation, what did they determine was the nitrogen composition of the DNA?
The DNA contained only 14N or a mixture of 15N and 14N.
The DNA contained only 14N.
The DNA contained only 15N.
The DNA contained only 15N or a mixture of 15N and 14N.
a.The DNA contained only 14N or a mixture of 15N and 14N.
b.The DNA contained only 14N.
c.The DNA contained only 15N.
d.The DNA contained only 15N or a mixture of 15N and 14N.
Explanation / Answer
It was found that the DNA contained only N14 or a mixture of N15 and N14. It has been done in 5 different generations and the result analyse that DNA has replicated semiconservatively means that each strand serves as template for synthesis of new and complementary strand of DNA.