Biopolymer

Biopolymers are natural polymers produced by the cells of living organisms, made of monomeric units covalently bonded into chains to form larger molecules. There are three main classes: polynucleotides such as RNA and DNA; polypeptides, including proteins and shorter amino-acid polymers such as collagen, actin and fibrin; and polysaccharides, linear or branched chains of sugar carbohydrates such as starch, cellulose and alginate. Other biopolymers include natural rubbers, suberin and lignin, cutin and cutan, melanin, and polyhydroxyalkanoates. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/