Which statement correctly describes a nucleotide's composition?

Which statement correctly describes a nucleotide's composition?

• A. Has three parts: a sugar, a base, and a phosphate group.
• B. Has two parts: a sugar and a base
• C. Is composed only of a sugar
• D. Contains a lipid moiety

Answer: (A)

Nucleotides are three-part units: a five-carbon sugar, a nitrogenous base, and a phosphate group. The sugar is deoxyribose in DNA or ribose in RNA; the base is one of the four options (adenine, thymine or uracil, cytosine, or guanine); and the phosphate group attaches to the sugar and enables joining with other nucleotides to form the sugar-phosphate backbone of nucleic acids. The lipid moiety is not part of a nucleotide, and if you had only sugar and base, that would be a nucleoside, lacking the phosphate necessary to link into a polymer.

Nucleotides are three-part units: a five-carbon sugar, a nitrogenous base, and a phosphate group. The sugar is deoxyribose in DNA or ribose in RNA; the base is one of the four options (adenine, thymine or uracil, cytosine, or guanine); and the phosphate group attaches to the sugar and enables joining with other nucleotides to form the sugar-phosphate backbone of nucleic acids. The lipid moiety is not part of a nucleotide, and if you had only sugar and base, that would be a nucleoside, lacking the phosphate necessary to link into a polymer.