Monomer: Difference between revisions
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A '''monomer''' (from [[Greek language|Greek]] ''mono'' "one" and ''meros'' "part") is a small [[molecule]] that may |
A '''monomer''' (from [[Greek language|Greek]] ''mono'' "one" and ''meros'' "part") is an [[atom]] or a small [[molecule]] that may [[chemical bonding|bind]] chemically to other monomers (as building blocks) and form a [[polymer]] or a [[monomer clusters|cluster]].<ref>''Introduction to Polymers'' 1987 R.J. Young Chapman & Hall ISBN 0-412-22170-5</ref> In the organic chemistry of the animal metabolism, the most common natural monomer is [[glucose]], which is linked by [[glycosidic bonds]] into polymers such as [[cellulose]] and [[starch]], and is over 76% of the weight of all plant matter.<ref>Cellulose. (2008). In ''[[Encyclopædia Britannica]]''. Retrieved March 22, 2009, from Encyclopædia Britannica Online.</ref> |
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==Natural monomers== |
==Natural monomers== |
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Revision as of 14:32, 22 May 2010
A monomer (from Greek mono "one" and meros "part") is an atom or a small molecule that may bind chemically to other monomers (as building blocks) and form a polymer or a cluster.[1] In the organic chemistry of the animal metabolism, the most common natural monomer is glucose, which is linked by glycosidic bonds into polymers such as cellulose and starch, and is over 76% of the weight of all plant matter.[2]
Natural monomers
Amino acids are natural monomers that polymerize at ribosomes to form proteins. Nucleotides, monomers found in the cell nucleus, polymerize to form nucleic acids – DNA and RNA. Glucose monomers can polymerize to form starches, glycogen or cellulose; xylose monomers can polymerise to form xylan. In all these cases the a hydrogen atom and a hydroxyl (-OH) group are lost to form H2O, and an oxygen atom links each monomer unit. Due to the formation of water as one of the products, these reactions are known as dehydration or condensation reactions.
Isoprene is a natural monomer and polymerizes to form natural rubber, most often cis-1,4-polyisoprene, but also trans-1,4-polyisoprene.
Molecular weight
The lower molecular weight compounds built from monomers are also referred to as dimers, trimers, tetramers, pentamers, octamers, 20-mers, etc. if they have 2, 3, 4, 5, 8, or 20 monomer units, respectively. [3] Any number of these monomer units may be indicated by the appropriate Greek prefix; eg a decamer is formed from 10 monomers. Larger numbers are often stated in English instead of Greek. Molecules made of a small number of momomer units, up to a few dozen, are called oligomers.
See also
Notes
- ^ Introduction to Polymers 1987 R.J. Young Chapman & Hall ISBN 0-412-22170-5
- ^ Cellulose. (2008). In Encyclopædia Britannica. Retrieved March 22, 2009, from Encyclopædia Britannica Online.
- ^ Campbell, Neil A. (2006). Biology: Exploring Life. Boston, Massachusetts: Pearson Prentice Hall. ISBN 0-13-250882-6.
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