Question

What was observed in the supernatant when Set A (³²P-labeled DNA) phages infected E. coli bacteria?

Options

• Highly radioactive

• Mostly not radioactive

• Completely radioactive

• Radioactivity increases over time

Answer 1

In Set A, the supernatant was mostly not radioactive, indicating that the ³²P-labeled DNA remained inside the bacterial cells and did not remain in the solution outside. This contrasted sharply with Set B results and provided evidence that DNA entered the cells while protein remained outside.