Question

32P can be used to make any nucleotide (A, C, G, or T) radioactive. Which of the following explains why this is true?

A.All nitrogenous bases have a phosphorus atom that can be replaced with 32P.
B.All nucleotides have a phosphorus atom that can be replaced with 32P.
C.All sugar molecules have a phosphorus atom that can be replaced with 32P.
D.All isotopes of phosphorus have 15 protons and are unstable.

Answer 1

B. The answer is: All nucleotides have a phosphorus atom that can be replaced with 32P.

Nucleotides contain a nitrogenous base, a five-carbon sugar, and, at least, one phosphate group. Exactly that phosphate group in the nucleotide has the phosphorus atom. Therefore, the phosphorus atom in the nucleotide can be replaced with radioactive phosphorus-32 (32P).