Question : Watson and Crick suggested the copying mechanism for DNA wherein the two strands separate and act as template for the synthesis of new complementary strands. Centrifugal force and the use of isotopes helped to prove the mechanism of replication in E. coli. Explain how it has helped.

Question : Watson and Crick suggested the copying mechanism for DNA wh

1.	Question : Watson and Crick suggested the copying mechanism for DNA wherein the two strands separate and act as template for the synthesis of new complementary strands. Centrifugal force and the use of isotopes helped to prove the mechanism of replication in E. coli. Explain how it has helped.
Answer» Solution :(Explanation of MESELSON Stahl.s experiment) E.coli GROWN in medium CONTAINING `""^15NH_4Cl`for MANY generations to get `""^15N`incorporated into newly synthesised DNA, then cells transferred into 14NHACI, extracted DNA are centrifuged in CsCl and measured to get their densities, DNA extracted from the culture after one generation/20 minutes, showed intermediate/hybrid density, DNA extracted after two generations/40 minutes showed light DNA and hybrid DNA