What are the basic structural units of proteins?

The basic structural units of proteins are amino acids. These organic compounds consist of an amino group, a carboxyl group, and a unique side chain, which distinguishes one amino acid from another. When amino acids link together through peptide bonds, they form polypeptides, which then fold into specific shapes to become functional proteins. Proteins play crucial roles in the body, serving as enzymes, hormones, structural components, and more, all of which are determined by the sequence and composition of the amino acids.

Carbohydrates are primarily involved in energy storage and supply, while fatty acids are the building blocks of lipids and have roles in energy storage and cellular structure. Nucleotides, on the other hand, are the structural units of nucleic acids such as DNA and RNA, which are essential for genetic information storage and transfer. Each of these options serves important functions within biological systems but does not serve as the fundamental building blocks of proteins.