What are the basic building blocks of nucleic acids?

• A. Nucleotides
• B. Amino acids
• C. Sugars
• D. Lipids

Answer: (A)

Nucleic acids are polymers built from nucleotides. Each nucleotide has three parts: a five‑carbon sugar (deoxyribose in DNA or ribose in RNA), a phosphate group, and a nitrogenous base. Nucleotides connect via phosphodiester bonds to create a sugar–phosphate backbone, with the bases protruding to store genetic information. The sequence of those bases determines the instructions cells use to make proteins and regulate activities. So nucleotides are the fundamental building blocks of nucleic acids. Other biomolecules have different monomers—amino acids for proteins, monosaccharides for carbohydrates, and lipids (built from fatty acids and glycerol) that don’t form long nucleotide-based polymers.