Elaborate Proteins?

Proteins:  Proteins are the primary constituents of most living cells. Proteins are important components of cell membranes, and they form structures such as hair, fingernails, muscle tissue, cartilage, ligaments, tendons, hemoglobin, antibodies, and enzymes. Enzymes control most of the metabolic processes in a cell. Proteins contain carbon, hydrogen, oxygen, and nitrogen, and lesser quantities of other elements. Their basic structure consists of monomers (single subunits) called amino acids, named after the amino group, or NH2 in each molecule, and the carboxyl group, COOH, that forms the negatively charged acid part of the molecule.