How did the Hershey and Chase experiment prove that DNA, not protein, functioned in controlling genetic inheritance?
By tagging the DNA of the infecting bacteriophage with radioactive sulfur, the infected bacterial cell became radioactive as DNA entered and took over control.
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.
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.
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.