What is the primary structure of proteins composed of?

The primary structure of proteins is composed of amino acids linked together by peptide bonds. This sequence of amino acids, which is unique for each protein, defines its specific characteristics and function. The arrangement and types of amino acids in the chain are crucial as they determine how the protein will fold and ultimately how it will function in a biological context. Peptide bonds are formed through a dehydration reaction between the carboxyl group of one amino acid and the amino group of another, resulting in a covalent bond that helps maintain the integrity of the protein's structure. This aspect of protein structure is foundational, as modifications or changes in this sequence can lead to varying biological activities and phenotypes.