Question

Choose the correct analogy with respect to the radioisotopes used in the Hershey-Chase experiment.

• A. ${}^{32}P$: DNA:: ${}^{35}S$: protein
• B. ${}^{32}P$: Protein:: ${}^{32}S$: DNA
• C. ${}^{35}P$: Protein:: ${}^{35}S$ : DNA
• D. ${}^{35}P$ : DNA:: ${}^{32}S$: protein

Answer 1

The correct option is A ${}^{32}P$: DNA:: ${}^{35}S$: protein

Radioactive isotopes of phosphorus and sulphur, ${}^{32}P$ and ${}^{35}S$, were used in Hershey and Chase’s experiment. Phosphorus forms an important constituent of DNA while sulphur is present in certain amino acids like methionine which are constituents of proteins. Therefore, ${}^{32}P$ gets incorporated into DNA and ${}^{35}S$ into the protein(capsid) of bacteriophage.