You label cells with a radioactive isotope of sulfur (³⁵S).The only molecules that would be radioactively labeled in these cells are:

Question

Quizplus · Accepted Answer

Proteins contain the sulfur-containing amino acid cysteine, which would be labeled with the radioactive sulfur isotope. Lipids and carbohydrates do not typically contain sulfur, and while nucleic acids do contain sulfur-containing molecules, they do not contain cysteine and would not be labeled with this specific isotope.

You Label Cells with a Radioactive Isotope of Sulfur (35S)

You Label Cells with a Radioactive Isotope of Sulfur (³⁵S)