Final answer:
Protein structure is organized into four levels: primary, secondary, tertiary, and quaternary. Each level contributes to the overall function of the protein.
Step-by-step explanation:
The structure of proteins is described as having four levels of organization: primary, secondary, tertiary, and quaternary. The primary structure refers to the sequence of amino acids in a protein's polypeptide chain. The secondary structure is the folding or coiling of the polypeptide chain, such as alpha helices or beta sheets. The tertiary structure refers to the three-dimensional shape of the protein, determined by interactions between amino acid side chains. The quaternary structure is the arrangement of multiple protein subunits into a functional complex.