What term describes the five-carbon sugar present in nucleotides?

• A. Nitrogen base
• B. Amino acid
• C. Mutation
• D. 5-carbon sugar

Answer: (D)

The main idea here is that nucleotides are built from three parts: a sugar, a phosphate group, and a nitrogenous base. The sugar part is a five-carbon ring, which makes it a pentose. This five-carbon sugar is what forms the backbone of nucleic acids when linked by phosphate groups, and it exists in two forms: ribose in RNA and deoxyribose in DNA. The term describing this component is the 5-carbon sugar (pentose). The other terms listed—nitrogen base, amino acid, and mutation—refer to other, unrelated aspects of biology and do not describe the sugar component of nucleotides.