Which components make up all nucleotides?

Which components make up all nucleotides?

• A. Amino acids, peptide bonds, phosphate
• B. Pentose sugar, nitrogen base, phosphate
• C. Glycerol, fatty acids, phosphate
• D. Glucose, base, phosphate

Answer: (B)

All nucleotides share three components: a pentose sugar, a nitrogenous base, and a phosphate group. The sugar is a five-carbon sugar—ribose in RNA or deoxyribose in DNA. The nitrogenous base attaches to the sugar and can be adenine, thymine, cytosine, or guanine in DNA (uracil replaces thymine in RNA). The phosphate group binds to the sugar and links nucleotides together to form the nucleic acid backbone. This trio—sugar, base, and phosphate—is the defining structure of nucleotides, including energy carriers like ATP, which have extra phosphate groups but retain the same basic components. Other listed molecules belong to different biomolecule classes (amino acids and peptide bonds for proteins; glycerol with fatty acids for lipids; glucose is a carbohydrate), so they don’t form nucleotides.

All nucleotides share three components: a pentose sugar, a nitrogenous base, and a phosphate group. The sugar is a five-carbon sugar—ribose in RNA or deoxyribose in DNA. The nitrogenous base attaches to the sugar and can be adenine, thymine, cytosine, or guanine in DNA (uracil replaces thymine in RNA). The phosphate group binds to the sugar and links nucleotides together to form the nucleic acid backbone. This trio—sugar, base, and phosphate—is the defining structure of nucleotides, including energy carriers like ATP, which have extra phosphate groups but retain the same basic components. Other listed molecules belong to different biomolecule classes (amino acids and peptide bonds for proteins; glycerol with fatty acids for lipids; glucose is a carbohydrate), so they don’t form nucleotides.