Question

How did Hershey and Chase prove that DNA is the genetic material?

Answer 1

Hint: Deoxyribonucleic acid (DNA) is a genetic/hereditary material. It is made of two polynucleotide chains, which are coiled and forms a double helix. The DNA is passed from one generation to another by making copies of itself.

Complete answer:
Two scientists Alfred Hershey and Martha Chase proved that DNA is a genetic material by working on bacteriophages.
1. The scientists grow viruses in a radioactive phosphorus medium and a radioactive sulphur medium.
2. After doing this, they observed that the viruses which were grown in radioactive phosphorus contained radioactive DNA. There was no presence of radioactive protein.
3. Viruses which were grown in radioactive sulphur contained radioactive protein. There was no radioactive DNA.
4. Then these radioactive bacteriophages were attached to E.coli bacteria. By blending them, the viral coats were removed. Then by centrifuging, the virus particles were separated.
5. Then they observed that the bacteria which was virus infected and had radioactive DNA was radioactive and the other one with radioactive protein was not radioactive, which clearly meant that DNA is the genetic material which passed from virus to the bacteria as protein does not pass from virus to bacteria.
6. This experiment was basically divided into three sections: Infection, Blending and Centrifugation.

Note: Bacteria which are infected by viruses are called bacteriophages. This experiment was done to check which one is the genetic material out of DNA and protein.