NEET BIOLOGY

Detailed explanation-1: -Radioactive elements 32P and 35S were used in Hershey and Chase’s experiments. Phosphorus and sulphur form important constituents of DNA (phosphorus) and certain amino acids (sulphur). Moreover, using the radioactive isotopes of these elements made it easier to trace them during the course of the experiment.

Detailed explanation-2: -The progeny of the phages that were labeled with radioactive phosphorus remained labeled, whereas the progeny of the phages labeled with radioactive sulfur were unlabeled. Thus, the Hershey–Chase experiment helped to confirm that DNA, not protein, is the genetic material.

Detailed explanation-3: -Since the protein coat was lighter, it was found in the supernatant while the infected bacteria got settled at the bottom of the centrifuge tube. Hence, it was proved that DNA is the genetic material as it was transferred from virus to bacteria.

Detailed explanation-4: -Complete answer: Two scientists Alfred Hershey and Martha Chase proved that DNA is a genetic material by working on bacteriophages.

Detailed explanation-5: -Hershey and Chase used the isotopes S35 and P32 to demonstrate that DNA is the genetic material in some viruses while Meselson and Stahl used the isotope N15 to demonstrate semi-conservative DNA replication. P32 is denser that standard P, and is found in DNA so possibly could be used to label new strands of DNA..