This document provides information on the basics of protein structure and function. It discusses the definition of proteins as polymers made from 20 different amino acids. The primary, secondary, tertiary, and quaternary structures of proteins are described. The primary structure refers to the amino acid sequence, secondary structure involves twisting into alpha helices or beta pleated sheets, tertiary structure is the 3D folding of these structures, and quaternary structure involves multiple protein subunits. The document also covers protein function and the role of proteins in carrying out the activities of cells.