Question

The DNA is a genetic material. It was proved conclusively by

• A. J.D. Watson
• B. Hershey and Chase
• C. Alfred Griffith
• D. Boveri and Sutton

Answer 1

Answer: (B)

Hershey and Chase

Hershey and chase performed experiments that confirmed that the DNA is the genetic material. They showed that when bacteriophages, which were composed of DNA and protein, infect bacteria, their DNA enter the host bacterial cells, but most of their protein do not.

Since phosphorus is contained in DNA, not amino acids, radiolabelled P-32 was used to label DNA. Radioactive S-35 was used to label protein since sulfur is not found in DNA.

The labeled progeny of bacteriophages was allowed to infect unlabelled bacteria. The phage coat remained outside the bacteria and only DNA entered. Disruption of phage from the bacteria by agitation followed by centrifugation allowed the separation of phage coats from bacteria. After the lysis of host to release phage progeny, it was found that the new progeny produced contained P-32 and not S-35. Thus, this experiment confirmed that DNA is the genetic material.

So, the correct option is 'Hershey and Chase'.