Question

Hershey and Chase's experiment with bacteriophage showed that:

• A. DNA contains radioactive sulphur.
• B. Protein gets into the bacterial cells.
• C. Viruses undergo transformation.
• D. DNA is the genetic material.

Hint:

Remember: $^{32}$P → DNA enters cell → DNA = genetic material.

Answer 1

The Correct Option is D

Concept: Hershey and Chase (1952) used bacteriophages to determine whether DNA or protein is the genetic material.
Step 1: Experimental setup.

• DNA was labeled with radioactive phosphorus ($^{32}$P)
• Protein was labeled with radioactive sulphur ($^{35}$S)

Step 2: Infection of bacteria.
Bacteriophages were allowed to infect bacterial cells.
Step 3: Observation.
Only radioactive phosphorus (DNA) entered the bacterial cells, while protein remained outside.
Step 4: Inference.
Since DNA entered the cell and directed viral replication, it must be the genetic material.
Step 5: Evaluating options.

• DNA contains radioactive sulphur $\rightarrow$ Incorrect (protein contains sulphur)
• Protein gets into bacterial cells $\rightarrow$ Incorrect
• Viruses undergo transformation $\rightarrow$ Incorrect
• DNA is the genetic material $\rightarrow$ Correct

Step 6: Conclusion.
Thus, the experiment proved that DNA is the genetic material.