Editing Monomer (section)

==Natural monomers==
Some of the main [[biopolymer]]s are listed below:

===Amino acids===
For ''proteins'', the monomers are [[amino acid]]s. Polymerization occurs at [[ribosome]]s. Usually about 20 types of amino acid monomers are used to produce proteins. Hence proteins are not homopolymers.

===Nucleotides ===
For polynucleic acids ([[DNA]]/[[RNA]]), the monomers are [[nucleotide]]s, each of which is made of a [[pentose]] sugar, a nitrogenous base and a phosphate group.  Nucleotide monomers are found in the [[cell nucleus]].  Four types of nucleotide monomers are precursors to DNA and four different nucleotide monomers are precursors to RNA.

===Glucose and related sugars===
For carbohydrates, the monomers are monosaccharides. The most abundant natural monomer is [[glucose]], which is linked by [[glycosidic bonds]] into the polymers [[cellulose]], [[starch]], and [[glycogen]].<ref>{{Cite journal|url = https://www.academia.edu/5082714|title = Biomolecules: Classification and structural properties of carbohydrates|website = Academia.edu|last = Ebuengan|first = Kaye}}</ref>

===Isoprene===
[[Isoprene]] is a natural monomer that polymerizes to form a [[natural rubber]], most often ''cis-''1,4-polyisoprene, but also ''trans-''1,4-polymer.  [[Synthetic rubber]]s are often based on [[butadiene]], which is structurally related to isoprene.