Question

Radioisotopes are frequently used to label molecules in a cell. The fate of atoms and molecules in a 18) ce'll can then be followed. Assume Saccharomyces cerevisiae is grown in a nutrient medium containing the radioisotope 3% After a 48-hour incubatir, the 35S would most likely be found in the S. cerevisiae's:____________.

A) nucleic acids.
B) proteins
C) carbohydrates
D) water
E) lipids

Answer 1

B) Proteins

Step-by-step explanation:

[³⁵S] is usually supplied as [³⁵S]methionine and [³⁵S]cysteine. These amino acids are incorporated into proteins.

A is wrong. Nucleic acids do not have sulfur in their molecules.

C and E wrong. The carbohydrates and lipids in S. cerevisiae have no sulfur.

D is wrong. Water has only H and O in its molecules.