Proteins are made from composite elements such as oxygen, hydrogen, carbon and nitrogen, and more commonly called quaternary. Each protein is constituted by the union of many smaller molecules that are called amino acids. The amino acids that make up proteins are twenty-six (26) of which some of these are called essential because they must be introduced in the diet. The structure of the proteins can be compared to a chain whose links are twenty amino acids, and can have a different length, doing so gives rise to many varieties of proteins.
