Why S35 is not present inside the bacteria and why D.N.A of bacteriophage is present inside the bacterial cell?
Answers
Answer:
Hershey and Chase worked with bacteriophage and E.coli to prove that DNA is the genetic material. They used different radioactive isotopes to label DNA and protein coat of bacteriophage. They grew some bacteriophages on a medium that contained radioactive phosphorus (32P) and some in another medium that contained radioactive sulphur (35S). These radioactive labelled phages were allowed to infect E.coli bacteria. Viruses grown in presence of radioactive phosphorus contained radioactive DNA but not radioactive protein as phosphorous is present only in DNA. Viruses grown on radioactive sulphur contained radioactive protein but not radioactive as DNA does not contain sulphur. It was found that bacteria which were infected with bacteriophages having radioactive DNA were radioactive, indicating that DNA was the genetic material that passed from the virus to the bacteria. Bacteria infected with viruses having radioactive proteins were not found radioactive, indicates that protein did not enter the bacteria from the viruses. RNA also contains phosphorous atoms. It contains the phosphate backbone of DNA. So, the bacteria grown in the medium containing 35 S as a sole source of sulphur shows its incorporation into protein.
solution.