How are proteins structured?

Proteins are structured as polymers composed of amino acids linked together by peptide bonds. Each amino acid contains a central carbon atom, an amino group, a carboxyl group, a hydrogen atom, and a unique side chain known as the R-group. The sequence of these amino acids determines the protein's unique structure and function. When amino acids are linked by peptide bonds, they form long chains known as polypeptides, which fold into distinct three-dimensional shapes critical for their biological activity.

The nature of this structure is pivotal for protein function, as variations in the sequence and composition of amino acids can lead to different protein types with varying roles, such as enzymes, hormones, or structural components in cells. Understanding that proteins arise from amino acids highlights their essential role in biological systems, differentiating them from other macromolecules like nucleic acids, lipids, and carbohydrates.