What is an example of a macromolecule composed of amino acid monomers?

Proteins are macromolecules that are specifically composed of amino acid monomers. These amino acids are linked together through peptide bonds to form polypeptide chains, which then fold into specific three-dimensional structures that define the function of the protein. Proteins play a crucial role in nearly every biological process, including catalysis (as enzymes), transport, structural roles, and signaling.

In contrast, carbohydrates consist of sugar molecules (monosaccharides) rather than amino acids. Lipids are made up of fatty acids and glycerol or other structures, while nucleic acids (such as DNA and RNA) are constructed from nucleotide monomers. Therefore, proteins stand out as the only macromolecule in the options that are directly formed from amino acids.