Phospholipid
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2008-06-25T23:44:12Z
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Date the maintenance tags or general fixes
{{Expand|date=June 2008}}
[[Image:Phospholipid.svg|thumb|185px|Phospholipid]]
[[Image:phospholipid_structure.png|thumb|185px|Twoad group of the molecule, highlighted in red.<BR>The '''U''' indicates the uncharged hydrophobic portion of the molecule, highlighted in blue.]]
[[Image:Phosphatidyl-Choline.svg|thumb|185px|[[Phosphatidyl choline]] is the major component of [[lecithin]]. It is also a source for [[choline]] in the synthesis of acetylcholine in cholinergic neurons.]]
'''Phospholipids''' are a class of [[lipids]], and a major component of all [[biological membrane]]s, along with [[glycolipid]]s, [[cholesterol]] and [[proteins]]. Understanding of the aggregation properties of these molecules is known as [[lipid polymorphism]] and forms part of current academic research.
==Amphipathic character==
Due to its polar nature, the head of a phospholipid is [[hydrophilic]] (attracted to [[water]]); the [[lipophilic]] (or often known as hydrophobic) tails are not attracted to water. When placed in water, phospholipids form one of a number of [[lipid phases]]. In biological systems this is restricted to [[bilayer]]s, in which the lipophilic tails line up against one another, forming a membrane with hydrophilic heads on both sides facing the water. This allows it to form [[liposomes]] spontaneously, or small lipid [[vesicle (biology)|vesicles]], which can then be used to transport materials into living organisms and study diffusion rates into or out of a cell membrane.
This membrane is partially permeable, capable of elastic movement, and has [[fluid]] properties, in which embedded proteins (integral or peripheral proteins) and phospholipid molecules are able to move laterally. Such movement can be described by the [[Fluid Mosaic Model]], that describes the membrane as a mosaic of lipid molecules that act as a solvent for all the substances and proteins within it, so proteins and lipid molecules are then free to diffuse laterally through the lipid matrix and migrate over the membrane. [[Cholesterol]] contributes to membrane fluidity by hindering the packing together of phospholipids. However, this model has now been superseded, as through the study of [[lipid polymorphism]] it is now known that the behaviour of lipids under physiological (and other) conditions is not simple.
== See also ==
*[[Alkylphosphocholines]]
* [[Antiphospholipid syndrome]]
* [[Biochemistry]]
* [[Lipid]]
* [[Lipid bilayer]] (e.g., [[Cell membrane]])
* [[Polymorphism (biophysics)]]
==References==
# J.M.Berg, J.L. Tymoczko, and L. Stryer, ''Biochemistry''. 5th ed. 2002, New York: W.H. Freeman. xxxviii, 974, [976] (various pages)
{{Membrane lipids}}
{{Phospholipids}}
[[Category:Phospholipids|*]]
[[bg:Фосфолипид]]
[[ca:Fosfolípid]]
[[cs:Fosfolipid]]
[[da:Fosfolipid]]
[[de:Phospholipide]]
[[et:Fosfolipiidid]]
[[es:Fosfolípido]]
[[fr:Phosphoacylglycérol]]
[[ko:인지질]]
[[hr:Fosfolipidi]]
[[id:Fosfolipid]]
[[is:Fosfólípið]]
[[it:Fosfolipide]]
[[he:פוספוליפיד]]
[[lb:Phospholipid]]
[[lt:Fosfolipidai]]
[[mk:Фосфолипид]]
[[nl:Fosfolipide]]
[[ja:リン脂質]]
[[pl:Fosfolipidy]]
[[pt:Fosfolípido]]
[[ru:Фосфолипиды]]
[[sl:Fosfolipid]]
[[fi:Fosfolipidi]]
[[sv:Fosfolipid]]
[[th:ฟอสโฟลิพิด]]
[[tr:Fosfolipit]]