Give an account of the Hershey and Chase experiment. What did it conclusively prove? If both $DNA$ and proteins contained phosphorus and sulphur,do you think the result would have been the same?

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(N/A) The unequivocal proof that $DNA$ is the genetic material came from the experiments of Alfred Hershey and Martha Chase $(1952)$. They worked with viruses that infect bacteria,called bacteriophages.
$1$. Experimental Setup: They grew some viruses on a medium containing radioactive phosphorus $(^{32}P)$ and others on a medium containing radioactive sulfur $(^{35}S)$. Since $DNA$ contains phosphorus but not sulfur,viruses grown in radioactive phosphorus had radioactive $DNA$. Conversely,since proteins contain sulfur but not phosphorus,viruses grown in radioactive sulfur had radioactive proteins.
$2$. Infection and Blending: These radioactive phages were allowed to infect $E. coli$ bacteria. After infection,the viral coats were removed from the bacterial surface by agitating them in a blender.
$3$. Centrifugation: The virus particles were separated from the bacteria by spinning them in a centrifuge. The heavier bacterial cells formed a pellet,while the lighter viral coats remained in the supernatant.
$4$. Conclusion: Bacteria infected with viruses containing radioactive $DNA$ $(^{32}P)$ were found to be radioactive,whereas bacteria infected with viruses containing radioactive proteins $(^{35}S)$ were not. This conclusively proved that $DNA$,not protein,is the genetic material that enters the bacteria.
$5$. Hypothetical Scenario: If both $DNA$ and proteins contained both phosphorus and sulfur,the experiment would not have been able to distinguish between the two. The radioactivity would have been present in both the pellet and the supernatant regardless of which molecule entered the cell,making it impossible to conclude which one was the genetic material.

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