Question

Predict the experimental outcome if Hershey and Chase had used a bacterial cell instead of a bacteriophage in the procedure.

1) Radioactivity would be detected in the supernatant but not in the pellet.
2) Radioactivity would be detected in the pellet but not in the supernatant.
3) Radioactivity would be detected in both the supernatant and pellet.
4) Radioactivity would be detected in neither the supernatant nor the pellet.

Answer 1

Using bacterial cells instead of a bacteriophage for the Hershey and Chase experiment would lead to radioactivity being detected in both the supernatant and the pellet, as bacterial cells contain both labeled DNA and proteins.

Step-by-step explanation:

If Hershey and Chase had used a bacterial cell in their experiment instead of a bacteriophage, and followed the same procedure, the experimental outcome would differ significantly. Let's assume that the bacterial cell is labeled with radioactive isotopes in the same manner - DNA with ³²P and proteins with ³⁵S. Since bacterial cells contain both DNA and proteins, after the centrifugation both the supernatant and the pellet would display radioactivity.

This is because both DNA and proteins are integral parts of bacterial cells, and during centrifugation, the entire bacterial cell (containing both labeled DNA and proteins) would sediment in the pellet. Therefore, unlike the original Hershey and Chase experiment which concluded that DNA is the carrier of genetic information into the cells, using bacterial cells would not lead to this conclusion since both components would co-sediment.

Thus, the expected outcome would be option 3) Radioactivity would be detected in both the supernatant and pellet, as cellular debris and some non-sedimented components could remain in the supernatant.