Why did Hershey and Chase use «35S’ and 32p’ in their experiment? Explain.

 Why did Hershey and Chase use «35S’ and 32p’ in their experiment? Explain.

Ans.

Hershey and Chase used radioactive isotopes of sulfur-35 (35S) and phosphorus-32 (32P) in their experiment to distinguish between protein and DNA in bacteriophages.

1. Sulfur-35 (35S) labels proteins: Proteins contain sulfur but no phosphorus. By incorporating 35S into the protein component of the bacteriophage, Hershey and Chase could track the location of proteins during viral infection.

2. Phosphorus-32 (32P) labels DNA: DNA contains phosphorus but no sulfur. By incorporating 32P into the DNA component of the bacteriophage, Hershey and Chase could track the location of DNA during viral infection.

Using these radioactive isotopes, Hershey and Chase were able to determine that only the DNA of the bacteriophage, not the protein, enters the bacterial cell during infection. This experiment provided strong evidence that DNA, not protein, is the genetic material responsible for heredity and inheritance.