Phospholipid

Phospholipid
The left image shows a phospholipid, and the right image shows the chemical makeup.
Phosphatidylcholine is the major component of lecithin. It is also a source for choline in the synthesis of acetylcholine in cholinergic neurons.
Cell membranes consist of phospholipid bilayers

Phospholipids are a class of lipids that are a major component of all cell membranes. They can form lipid bilayers because of their amphiphilic characteristic. The structure of the phospholipid molecule generally consists of two hydrophobic fatty acid "tails" and a hydrophilic "head" consisting of a phosphate group. The two components are joined together by a glycerol molecule. The phosphate groups can be modified with simple organic molecules such as choline, ethanolamine or serine.

The first phospholipid identified in 1847 as such in biological tissues was lecithin, or phosphatidylcholine, in the egg yolk of chickens by the French chemist and pharmacist, Theodore Nicolas Gobley. Biological membranes in eukaryotes also contain another class of lipid, sterol, interspersed among the phospholipids and together they provide membrane fluidity and mechanical strength. Purified phospholipids are produced commercially and have found applications in nanotechnology and materials science.[1]

Amphiphilic character

An amphiphile (from the Greek αμφις, amphis: both and φιλíα, philia: love, friendship) is a term describing a chemical compound possessing both hydrophilic (water-loving, polar) and lipophilic (fat-loving, non-polar) properties. The phospholipid head contains a negatively charged phosphate group and glycerol; it is hydrophilic. The phospholipid tails usually consist of 2 long fatty acid chains; they are hydrophobic and avoid interactions with water. When placed in aqueous solutions, phospholipids are driven by hydrophobic interactions that result in the fatty acid tails aggregating to minimize interactions with water molecules. These specific properties allow phospholipids to play an important role in the phospholipid bilayer. In biological systems, the phospholipids often occur with other molecules (e.g., proteins, glycolipids, sterols) in a bilayer such as a cell membrane.[2] Lipid bilayers occur when hydrophobic tails line up against one another, forming a membrane of hydrophilic heads on both sides facing the water.

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. Sterols contribute 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.[citation needed]

Diacylglyceride structures

See: Glycerophospholipid

Phosphosphingolipids

See Sphingolipid

  • Ceramide phosphorylcholine (Sphingomyelin) (SPH)
  • Ceramide phosphorylethanolamine (Sphingomyelin) (Cer-PE)
  • Ceramide phosphoryllipid
Other Languages
العربية: دهن فسفوري
български: Фосфолипид
bosanski: Fosfolipid
català: Fosfolípid
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dansk: Fosfolipid
Deutsch: Phospholipide
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español: Fosfolípido
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فارسی: فسفولیپید
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日本語: リン脂質
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Simple English: Phospholipid
slovenčina: Fosfolipid
slovenščina: Fosfolipid
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українська: Фосфоліпіди
Tiếng Việt: Phospholipid
中文: 磷脂