Question

Hershey and Chase designed an experiment using radioactive isotopes of sulphur and phosphorus to keep separate track of the viral proteins and nucleic acids during the infection process. Which bacteriophage and bacterium were used for this experiment?

• A. T2 bacteriophage and E. coli
• B. T4 bacteriophage and Bacillus
• C. T2 bacteriophage and Salmonella
• D. T4 bacteriophage and E. coli

Hint:

Think "S for Sulfur and Shell" (proteins form the outer capsid shell of the virus) and "P for Phosphorus and Passage" (DNA enters the bacterium).

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
In 1952, Alfred Hershey and Martha Chase conducted experiments to confirm whether DNA or protein was the genetic material of living organisms.
They utilized the principle that proteins contain sulfur but no phosphorus, while DNA contains phosphorus but no sulfur.

Step 2: Detailed Explanation:
Hershey and Chase selected the T2 bacteriophage, a bacterial virus that infects its host by attaching to the outer membrane and injecting its genetic material.
The host organism used was the bacterium Escherichia coli (E. coli).
In the experiment, they prepared two batches of T2 phage:
One batch was grown in media containing radioactive sulfur (\(^{35}S\)), labeling the viral proteins.
The other batch was grown in media containing radioactive phosphorus (\(^{32}P\)), labeling the viral DNA.
After allowing the phages to infect E. coli, they agitated the samples in a blender to shear off the viral capsids and centrifuged them.
They observed that only the \(^{32}P\)-labeled DNA entered the bacterial cells, whereas the \(^{35}S\)-labeled protein capsids remained in the supernatant.
This demonstrated that DNA is the genetic material injected into host cells to direct viral replication.

Step 3: Final Answer:
The Hershey-Chase experiment utilized T2 bacteriophage and Escherichia coli.