Editing Biological membrane (section)

=== Oligosaccharides ===
[[Oligosaccharide]]s are sugar containing polymers. In the membrane, they can be covalently bound to lipids to form [[glycolipid]]s or covalently bound to proteins to form [[glycoprotein]]s. Membranes contain sugar-containing lipid molecules known as glycolipids. In the bilayer, the sugar groups of glycolipids are exposed at the cell surface, where they can form hydrogen bonds.<ref name=":7">{{Cite journal|title = Protein transport across membranes: Comparison between lysine and guanidinium-rich carriers|journal = Biochimica et Biophysica Acta (BBA) - Biomembranes|date = 2015-11-01|pages = 2980–2984|volume = 1848|issue = 11, Part A|doi = 10.1016/j.bbamem.2015.09.004|pmid = 26342679|pmc = 4704449|first1 = Max|last1 = Lein|first2 = Brittany M.|last2 = deRonde|first3 = Federica|last3 = Sgolastra|first4 = Gregory N.|last4 = Tew|first5 = Matthew A.|last5 = Holden}}</ref> Glycolipids provide the most extreme example of asymmetry in the lipid bilayer.<ref name=":1" /> Glycolipids perform a vast number of functions in the biological membrane that are mainly communicative, including cell recognition and cell-cell adhesion. Glycoproteins are integral proteins.<ref name=":2" /> They play an important role in the immune response and protection.<ref>{{Cite journal|title = General N-and O-Linked Glycosylation of Lipoproteins in Mycoplasmas and Role of Exogenous Oligosaccharide|journal = PLOS ONE|date = 2015-11-23|pmc = 4657876|pmid = 26599081|pages = e0143362|volume = 10|issue = 11|doi = 10.1371/journal.pone.0143362|first1 = James M.|last1 = Daubenspeck|first2 = David S.|last2 = Jordan|first3 = Warren|last3 = Simmons|first4 = Matthew B.|last4 = Renfrow|first5 = Kevin|last5 = Dybvig|bibcode = 2015PLoSO..1043362D|doi-access = free}}</ref>