Monomer is a small molecule that makes up the polymer, the bigger molecule. However, its existence is not just to help make polymers. In Greek, the word ‘monomer’ means ‘one’ (mono) and ‘part’ (mer), or one part. The monomer molecule typically has 4 to 10 atoms. The molecule bonds with another monomer through polymerization, the bond being a covalent bond.
Vinyl chloride, glucose, and amino acids are monomers. Glucose is a common natural monomer, which forms glycosidic bonds during polymerization. A glucose monomer can polymerize and form into glycogen, cellulose or starch. Plants conserve energy as starch; animals, on the other hand, store energy as glycogen.
Amino acids can polymerize into proteins, peptides, and polypeptides. Similarly, fatty acids and glycerol are monomers that polymerize to form lipids. Nucleotides polymerize into nucleic acids – for instance, DNA. Monosaccharides or simple sugars can polymerize to form carbohydrates. Vinyl chlorides, which are man-made monomers, polymerize into polyvinyl chloride (PVC) – an abundantly used plastic material.
As aforementioned, a monomer can bond with other molecules. The total number of molecules that a monomer can bond with is ascertained by the total number of active locations where the monomer has to form covalent bond(s). When a monomer bonds with one or two monomer, the resulting structure is linear, or like a long chain. However, if a monomer bonds with more than two monomers simultaneously, the resulting structure looks like a stacked group of monomers.