question_answer

State the reason behind using \[^{35}S\]and \[^{32}P\]in the experiments conducted by Hershey and Chase to establish that DNA acts as a genetic material,

Answer:

Hershey and Chase (1952) worked with viruses that infect bacteria, i.e. bacteriophages to prove that DNA is the genetic material. For this, they grew some bacteriophages on a medium containing radioactive\[^{32}P\], while another set of viruses was grown on\[^{35}S\]medium. Viruses grown on medium supplemented with\[^{32}P\]contained radioactive DNA, but not the radioactive protein, because only DNA contains phosphorus. While on the other hand, viruses grown on medium supplemented with radioactive\[^{35}S\], contained radioactive protein but not the radioactive DNA because DNA does not contain sulphur. Both types of radioactive viruses were allowed to infect E. coli separately. It was found that phage with radioactive protein did not make the bacteria radioactive, only phage with radioactive DNA did. Thus, suggesting that DNA acts as a genetic material.