Question

How did the Hershey and Chase experiment prove that DNA, not protein, functioned in controlling genetic inheritance?

• A. By tagging the DNA of the infecting bacteriophage with radioactive sulfur, the infected bacterial cell became radioactive as DNA entered and took over control.
• B. The protein coat of the bacteriophage was tagged with both radioactive phosphorus and sulfur and would go undetected within the infected bacterial cell since only the DNA molecule enters.
• C. Radioactive carbon was used to tag both DNA and the protein coat of the infecting bacteriophage which would be detected within the infected bacterial cell as both molecules enter.
• D. Phosphate was used to tag DNA because DNA contains phosphorus within its structure (specifically the backbone), while proteins do not, and would make the bacterial cell radioactive as DNA entered and took over control.

Answer 1

The correct option is D Phosphate was used to tag DNA because DNA contains phosphorus within its structure (specifically the backbone), while proteins do not, and would make the bacterial cell radioactive as DNA entered and took over control.

In 1952, scientist Alfred Hershey and Martha Chase did a series of experiments to help confirm that DNA is the genetic material. Before this experiment, many scientists still used to think that proteins are the genetic material. So, to prove this they used bacteriophages they took the sulphur labelled protein capsuled bacteriophage and phosphorus labelled DNA. The main reason for taking the Radioactive isotope of the normal sulphur and phosphate was because it is easier to differentiate so after the series of experiments of infecting the bacteriophages in the cell and then removing the genetic material with the help of centrifugation it was found that the DNA of the cell contain radioactively label Phosphorus but not sulphur it went on to prove that genetic material is the DNA and not proteins.

So, the correct option is 'Phosphate was used to tag DNA because DNA contains phosphorus within its structure (specifically the backbone), while proteins do not, and would make the bacterial cell radioactive as DNA entered and took over control.'