What is the structure of a nucleotide?

What is the structure of a nucleotide?

• A. A nucleotide consists of a nitrogenous base, a sugar, and a phosphate
• B. A nucleotide is composed of amino acids
• C. A nucleotide contains a triglyceride and a phosphate
• D. A nucleotide is a sugar molecule with a base

Answer: (A)

The structure being tested is what makes up a nucleotide. A nucleotide is built from three parts: a nitrogenous base, a five‑carbon sugar (deoxyribose in DNA or ribose in RNA), and a phosphate group. The base attaches to the sugar, and the phosphate group attaches to the sugar as well, enabling nucleotides to link together into the nucleic acid backbone through phosphodiester bonds. This combination is essential for both the information-carrying capacity and the polymerization of DNA and RNA. The other ideas describe different biomolecules or an incomplete nucleotide. Amino acids form proteins, triglycerides are fats, and saying a nucleotide is just a sugar with a base omits the phosphate group that is crucial for nucleotide identity and for linking units in nucleic acids.

The structure being tested is what makes up a nucleotide. A nucleotide is built from three parts: a nitrogenous base, a five‑carbon sugar (deoxyribose in DNA or ribose in RNA), and a phosphate group. The base attaches to the sugar, and the phosphate group attaches to the sugar as well, enabling nucleotides to link together into the nucleic acid backbone through phosphodiester bonds. This combination is essential for both the information-carrying capacity and the polymerization of DNA and RNA.

The other ideas describe different biomolecules or an incomplete nucleotide. Amino acids form proteins, triglycerides are fats, and saying a nucleotide is just a sugar with a base omits the phosphate group that is crucial for nucleotide identity and for linking units in nucleic acids.