Which statement best describes a nucleotide?

Which statement best describes a nucleotide?

• A. Nitrogenous base
• B. Monomer of nucleic acids made up of a five-carbon sugar, a phosphate group, and a nitrogenous base
• C. A polymer of amino acids
• D. A type of lipid

Answer: (B)

Nucleotides are the building blocks of nucleic acids, and a nucleotide is defined by three parts: a five-carbon sugar, a phosphate group, and a nitrogenous base. The sugar (ribose in RNA or deoxyribose in DNA) provides the molecular backbone, the phosphate group links sugars together to form the polymer chain, and the nitrogenous base stores the genetic information that encodes instructions for organisms. The combination of these three components makes a nucleotide a true monomer of DNA and RNA, whereas a nitrogenous base by itself lacks the sugar and phosphate to form a nucleotide. A polymer of amino acids describes proteins, and a lipid refers to a distinct class of fats and related molecules, not nucleotides.

Nucleotides are the building blocks of nucleic acids, and a nucleotide is defined by three parts: a five-carbon sugar, a phosphate group, and a nitrogenous base. The sugar (ribose in RNA or deoxyribose in DNA) provides the molecular backbone, the phosphate group links sugars together to form the polymer chain, and the nitrogenous base stores the genetic information that encodes instructions for organisms. The combination of these three components makes a nucleotide a true monomer of DNA and RNA, whereas a nitrogenous base by itself lacks the sugar and phosphate to form a nucleotide. A polymer of amino acids describes proteins, and a lipid refers to a distinct class of fats and related molecules, not nucleotides.