Editing Metabolism (section)

===Lipids===
{{Main|Biolipid}}
Lipids are the most diverse group of biochemicals. Their main structural uses are as part of internal and external [[biological membrane]]s, such as the [[cell membrane]].<ref name="Nelson-2005"/> Their [[chemical energy]] can also be used. Lipids contain a long, non-polar [[Aliphatic compound|hydrocarbon chain]] with a small polar region containing oxygen. Lipids are usually defined as [[hydrophobe|hydrophobic]] or [[amphiphiles|amphipathic]] biological molecules but will dissolve in [[organic solvent]]s such as [[ethanol]], [[benzene]] or [[chloroform]].<ref>{{cite journal | vauthors = Fahy E, Subramaniam S, Brown HA, Glass CK, Merrill AH, Murphy RC, Raetz CR, Russell DW, Seyama Y, Shaw W, Shimizu T, Spener F, van Meer G, VanNieuwenhze MS, White SH, Witztum JL, Dennis EA | display-authors = 6 | title = A comprehensive classification system for lipids | journal = Journal of Lipid Research | volume = 46 | issue = 5 | pages = 839–61 | date = May 2005 | pmid = 15722563 | doi = 10.1194/jlr.E400004-JLR200 | doi-access = free }}</ref> The [[fat]]s are a large group of compounds that contain [[fatty acid]]s and [[glycerol]]; a glycerol molecule attached to three fatty acids by [[ester]] linkages is called a [[triglyceride|triacylglyceride]].<ref>{{cite web|title=Lipid nomenclature Lip-1 & Lip-2|url=https://www.qmul.ac.uk/sbcs/iupac/lipid/lip1n2.html#p11|access-date=2020-06-06|website=qmul.ac.uk|archive-date=6 June 2020|archive-url=https://web.archive.org/web/20200606140055/https://www.qmul.ac.uk/sbcs/iupac/lipid/lip1n2.html#p11|url-status=live}}</ref> Several variations of the basic structure exist, including backbones such as [[sphingosine]] in [[sphingomyelin]], and [[hydrophile|hydrophilic]] groups such as [[phosphate]] in [[phospholipid]]s. [[Steroid]]s such as [[sterol]] are another major class of lipids.<ref>{{cite book|edition=8|title=Biochemistry|location=New York|isbn=978-1-4641-2610-9|oclc=913469736 | vauthors = Berg JM, Tymoczko JL, Gatto Jr GJ, Stryer L |date=8 April 2015|publisher=W. H. Freeman|pages=362}}</ref>