Molecular Basis of Inheritance Question 3
3. Which scientist experimentally proved that DNA is the sole genetic material in bacteriophage?
(a) Jacob and Monod
(b) Beadle and Tautum
(c) Messelson and Stahl
(d) Hershey and Chase
Show Answer
Answer : d
Hints & Solution
(d) Alfred Hershey and Martha Chase studied bacteriophages, or viruses that attack bacteria. In 1952 , they conducted a series of experiments to prove that DNA is the genetic material. They labelled the protein of bacteriophages with radioactive sulphur and their DNA with radioactive phosphorus. The bacteriophages were allowed to infect bacteria. The protein coat is left behind when the viral DNA enters a bacterium. Hershey and Chase wanted to find out which part of the bacteriophage will enter the bacteria and pass on genetic material - protein coat or DNA core. The proteins were labeled with radioactive sulfur-35, while DNA contained radioactive phosphorus-32. When they joined labeled viruses and bacteria, they discovered that phosphorus-32 was present in the bacteria. This outcome supported Avery’s theory that genes are located in the DNA of the cell.
