Question

Hershey and Chase experimented with radioactively labeled phosphorus and sulphur to determine that DNA and not protein is the genetic material. Which of the following was essential to this confirming experiment?

• A. Sulphur is present in amino acids in the protein coat of bacteria
• B. Phosphorus is present in high amounts in DNA
• C. Phosphorus is not present in amino acids in the protein coat of bacteria
• D. All of the above were critical to demonstrating DNA is involved in the genetic material

Answer 1

The correct option is D All of the above were critical to demonstrating DNA is involved in the genetic material

The unequivocal proof that DNA is the genetic material came from the experiments of Alfred Hershey and Martha Chase (1952). They worked with viruses that infect bacteria called bacteriophages. They worked to discover whether it was protein or DNA from the virus that entered the bacteria. They grew some viruses on a medium that contained radioactive phosphorus and some others on a medium that contained sulfur. Viruses grown in the presence of radioactive phosphorus contained radioactive DNA but not radioactive protein because DNA contains phosphorus but protein does not. Similarly, viruses grown on radioactive sulfur contained radioactive protein but not radioactive DNA because DNA does not contain sulfur.

So, the correct option is 'All the above were critical to demonstrating DNA is involved in the genetic material'.