The Precursor of Each New Nucleotide in a Strand of DNA

Question

The precursor of each new nucleotide in a strand of DNA is a
A) deoxynucleoside 5ʹ-diphosphate.
B) deoxynucleoside 3ʹ-diphosphate.
C) deoxynucleoside 5ʹ-triphosphate.
D) deoxynucleoside 3ʹ-triphosphate.

Accepted Answer

The precursor of each new nucleotide in a strand of DNA is a deoxynucleoside 5ʹ-triphosphate, which contains the base, deoxyribose sugar, and three phosphate groups. During DNA synthesis, the two outer phosphate groups are cleaved, releasing energy and forming a phosphodiester bond between adjacent nucleotides in the growing strand. Choice C is the only option that includes "5ʹ-triphosphate," making it the correct answer.