Question

What was the finding of Hershey and Chase?

• A. The viral infecting agent is RNA.
• B. The viral infecting agent is DNA.
• C. The viral infecting agent is protein.
• D. The $T_2$ virus has RNA as its genetic material.

Answer 1

The correct option is B The viral infecting agent is DNA.

Alfred Hershey and M. Chase (1952), gave unequivocal proof that DNA is the genetic material.
In their experiment, radioactive phosphorus $\left({}^{32}P\right)$ and radioactive sulphur $\left({}^{35}S\right)$ were used to culture bacteriophages. The DNA of bacteriophage was radiolabeled with ${}^{32}P$ and protein with ${}^{35}S$.
These radiolabeled bacteriophages were then made to infect E. coli bacterial cells. It was seen that the bacterial cells contained radioactive viral DNA $\left({}^{32}P\right)$, but not radioactive viral protein$\left({}^{35}S\right)$. This means that the bacteriophages transferred their DNA to the E. coli bacteria.
Hence this experiment proved that the DNA, and not protein, is the genetic material passed from the virus to bacteria.
$T_2$ bacteriophage(virus) has linear double-stranded DNA as its genetic material.