Question

Deoxyribonucleotides lack a

a) nitrogenous base.
b) 5′ phosphate group.
c) 3′ hydroxyl group.
d) 2′ hydroxyl group.
e) pentose sugar.

Answer 1

Deoxyribonucleotides lack the 2′ hydroxyl group, which is found in ribonucleotides.

Step-by-step explanation:

The correct answer is d) 2' hydroxyl group.

The pentose sugar in DNA is deoxyribose, which has a hydrogen atom attached to the 2' carbon. This is in contrast to ribose, the pentose sugar in RNA, which has a hydroxyl group attached to the 2' carbon. Deoxyribonucleotides are the building blocks of DNA, and each one is composed of three main components: a nitrogenous base, a pentose sugar called deoxyribose, and one or more phosphate groups. Specifically, the deoxyribose sugar is distinguished from ribose (found in RNA) by the lack of an oxygen atom at the 2' carbon—it has a hydrogen atom instead. Therefore, the part that deoxyribonucleotides lack when compared to ribonucleotides is the 2′ hydroxyl group.