Question

Which of the following best describes the results from Hershey and Chase’s experiment using bacterial viruses with; S-labeled proteins or; P-labeled DNA that are consistent with protein being the molecule responsible for hereditary?

a) Radioactive protein entered the bacterial cells
b) Radioactive DNA entered the bacterial cells
c) Radioactive protein remained outside the bacterial cells
d) Radioactive DNA remained outside the bacterial cells

Answer 1

Hershey and Chase's experiment demonstrated that DNA is the molecule responsible for heredity, as radioactive phosphorus (32P) labeled DNA was found in the bacterial cells after infection, while radioactive sulfur (35S) labeled protein remained outside.

Step-by-step explanation:

The Hershey and Chase experiment was a pivotal study in molecular biology that provided clear evidence that DNA, not protein, is the hereditary material in organisms. In this experiment, Hershey and Chase used radioactive sulfur (35S) to label proteins and radioactive phosphorus (32P) to label DNA in bacteriophages, which are viruses that infect bacteria. They then allowed these labeled phages to infect E. coli bacteria. After the process of infection, they used a blender to separate the phage protein coats from the bacteria and centrifuged the mixture. This resulted in a pellet of bacterial cells and a supernatant containing the remnants of the phage coats.

Based on their results, radioactive DNA (32P) was found inside the bacterial cells while the radioactive protein (35S) remained outside in the supernatant. This indicated that it was the DNA that entered the cells and carried the genetic information for producing more phages, not the protein. Therefore, the option consistent with the results that indicate protein as the hereditary molecule is incorrect. Hershey and Chase's actual findings confirmed that DNA was the molecule responsible for hereditary, not protein.