What are the building blocks of proteins?

Amino acids are the building blocks of proteins because they are the fundamental units that link together through peptide bonds to form polypeptides and ultimately create the complex structures of proteins. Each amino acid consists of a central carbon atom, an amino group, a carboxyl group, and a distinctive side chain or R group that determines the specific properties and identity of the amino acid.

In biological systems, the sequence of amino acids in a protein determines its unique structure and function. For example, enzymes, hormones, and structural components within cells are all proteins that perform diverse roles, which are dictated by their amino acid composition and arrangement.

The other options, while representing important biological macromolecules, do not serve as the building blocks of proteins. Fatty acids are the building blocks of lipids; nucleotides are the building blocks of nucleic acids such as DNA and RNA; and carbohydrates consist of sugar molecules, which serve as energy sources and structural components in cells. Understanding the role of amino acids helps clarify the foundation of protein synthesis and its significance in biology.