Which components make up a DNA nucleotide?

• A. Ribose sugar, a phosphate group, and a nitrogenous base
• B. Deoxyribose sugar, a phosphate group, and a nitrogenous base
• C. A nitrogenous base with no sugar
• D. Only a sugar and a phosphate

Answer: (B)

DNA nucleotides consist of three components: a deoxyribose sugar, a phosphate group, and a nitrogenous base. The sugar is deoxyribose, which distinguishes DNA from RNA (RNA uses ribose). The phosphate group links to the sugar to form the backbone of the strand, while the nitrogenous base attaches to the 1' carbon of the sugar and provides the information content through base pairing (A with T, C with G). The correct option includes all three parts, whereas a molecule with only ribose would be an RNA nucleotide, a base without sugar isn’t a nucleotide, and a sugar–phosphate pair lacks the information-carrying base.