What are the basic units of the DNA molecule, composed of a sugar, a phosphate, and one of four DNA bases?

What are the basic units of the DNA molecule, composed of a sugar, a phosphate, and one of four DNA bases?

• A. Amino acids
• B. Bases
• C. Nucleotides
• D. Nucleosides

Answer: (C)

DNA is built from nucleotides, each carrying a deoxyribose sugar, a phosphate group, and a nitrogenous base. This combination is the fundamental unit that links through phosphodiester bonds to form the long DNA polymer. The sequence of these bases along the chain stores genetic information, with base pairing between strands helping to stabilize the double helix. Amino acids are the building blocks of proteins, not DNA units. A base is only one component of a nucleotide. A nucleoside is sugar plus base without the phosphate group, so it lacks the backbone linkage that nucleotides provide.

DNA is built from nucleotides, each carrying a deoxyribose sugar, a phosphate group, and a nitrogenous base. This combination is the fundamental unit that links through phosphodiester bonds to form the long DNA polymer. The sequence of these bases along the chain stores genetic information, with base pairing between strands helping to stabilize the double helix.

Amino acids are the building blocks of proteins, not DNA units. A base is only one component of a nucleotide. A nucleoside is sugar plus base without the phosphate group, so it lacks the backbone linkage that nucleotides provide.