Final answer:
Protein structure comprises primary, secondary, tertiary, and quaternary levels. The primary structure is the sequence of amino acids. The secondary structure includes helices and sheets. The tertiary structure is the protein's overall shape. And the quaternary structure forms when multiple protein molecules interact.
Step-by-step explanation:
The structure of protein can be studied under four different levels of organization: primary, secondary, tertiary, and quaternary. The primary structure of a protein refers to the total number of amino acids and their sequence in that particular protein.
The secondary structure refers to configurations such as helices and sheets within polypeptide chains. The tertiary structure is a protein's overall three-dimensional shape, which controls the molecule's basic function. And finally, the quaternary structure forms when multiple protein molecules join together and function as a complex.