A diagonal molecular slab from the DPPC lipid bilayer simulation1; color scheme: PO4 - green, N(CH3)3 - violet, water - blue, terminal CH3 - yellow, O - red, glycol C - brown, chain C - grey.

A lipid bilayer or bilayer lipid membrane is a membrane or zone of a membrane composed of lipid molecules (usually phospholipids). The lipid bilayer is a critical component of all biological membranes, including cell membranes, and is a prerequisite for cell-based organisms. http://helix. ... http://helix. ... It has been suggested that Net flux be merged into this article or section. ... Figure 1: Structure of a Lipid. ... Two schematic representations of a phospholipid. ... A biological membrane or biomembrane is a membrane which acts as a barrier within or around a cell. ... Drawing of a cell membrane A component of every biological cell, the selectively permeable cell membrane (or plasma membrane or plasmalemma) is a thin and structured bilayer of phospholipid and protein molecules that envelopes the cell. ... Cells in culture, stained for keratin (red) and DNA (green). ... In biology and ecology, an organism (in Greek organon = instrument) is a complex adaptive system of organs that influence each other in such a way that they function as a more or less stable whole and have properties of life. ...

Structure and function

The structure of a bilayer explains its possible function as a barrier. Lipids are fats, like oil, and are insoluble in water. There are two important regions of a lipid that provide the structure of the lipid bilayer: the hydrophilic region, also called the polar head region, and the hydrophobic, or nonpolar tail region. The hydrophilic region is attracted to aqueous water while the hydrophobic region is repelled from it. Since lipid molecules contain regions that are both polar and nonpolar, they are called amphipathic molecules. This article or section is in need of attention from an expert on the subject. ... Oil is a generic term for organic liquids that are not miscible with water. ... The adjective hydrophilic describes something that likes water (from Greek hydros = water; philos = friend). ... In chemistry, hydrophobic or lipophilic species, or hydrophobes, tend to be electrically neutral and nonpolar, and thus prefer other neutral and nonpolar solvents or molecular environments. ... An amphipathic (a. ...

The bilayer is composed of two opposing layers of lipid molecules arranged so that their hydrocarbon tails face one another and form an oily core, while their electrically charged heads face the aqueous solutions on either side of the membrane. Hydrocarbons are refined at oil refineries and processed at chemical plants In chemistry, a hydrocarbon is any chemical compound that consists only of the elements carbon (C) and hydrogen (H). ...

Because of the oily core, a pure lipid bilayer is permeable to small hydrophobic solutes, but has only a very low permeability barrier to inorganic ions and other hydrophilic molecules. In chemistry, hydrophobic or lipophilic species, or hydrophobes, tend to be electrically neutral and nonpolar, and thus prefer other neutral and nonpolar solvents or molecular environments. ... // An ion is an atom, group of atoms, or subatomic particle with a net electric charge. ... The adjective hydrophilic describes something that likes water (from Greek hydros = water; philos = friend). ...

Model lipid bilayers

Within a critical range of concentrations, certain kinds of lipids alone in a test tube of water will self-organize to form a "bilayer", often referred to as bilayer lipid membranes (BLMs). Such membranes can be used in research, for instance on their electrical behavior (using the patch clamp technique, for example). Self-organization refers to a process in which the internal organization of a system, normally an open system, increases automatically without being guided or managed by an outside source. ... Classical Patch Clamp => Electrophysiology Planar Patch Clamp Automated Patch Clamp Device ...

Model bilayers can be produced using one of three methods:

1. Over an aperture between two aqueous solutions, where it is called a black BLM. The advantage of this method is the ability to control the constituents of each side of the membrane. The disadvantage of this method is that it causes the membrane to be fairly unstable, and rupture is certain in a matter of hours.
2. Over an electrode patterned on a substrate, where it is called a supported BLM or s-BLM. This method has the advantage of producing an extremely stable membrane, which in some cases may last several days before rupture. It also allows clean and specific electrical measurements thanks to the large experimental knowledge in electrical engineering for electrode patterning. Unfortunately this method has a major drawback in that it is possible to control the solution only on the side of the membrane that is not in contact with the electrode. (Although studies show that a 1 nanometer-thick water layer forms between the membrane and the electrode, this is of insufficient volume for controlling the solution composition.)
3. Over a polymer cushion. This more recent technique allows a combination the first two methods. Electrodes are patterned over a surface and a polymer (typically a hydrogel of cellulose gel) is coated on top of these electrodess. This polymer will act as a stabilizer for the membrane and also a spacer from the solid substrate.

In optics, an aperture is something which restricts the diameter of the light path through one plane in an optical system. ... Dissolving table salt in water In chemistry, a solution is a homogeneous mixture composed of one or more substances known as solutes that are dissolved in another substance known as a solvent. ... It has been suggested that Net flux be merged into this article or section. ... It has been suggested that Net flux be merged into this article or section. ... An electrode is a conductor used to make contact with a nonmetallic part of a circuit (e. ... The word substrate can mean the following: In biochemistry, a substrate is a molecule which is acted upon by an enzyme. ... It has been suggested that Net flux be merged into this article or section. ... This article treats electronics engineering as a subfield of electrical engineering, though this is not typical use in some areas. ... A nanometre (American spelling: nanometer) is 1. ... It has been suggested that Net flux be merged into this article or section. ... An electrode is a conductor used to make contact with a nonmetallic part of a circuit (e. ... Dissolving table salt in water In chemistry, a solution is a homogeneous mixture composed of one or more substances known as solutes that are dissolved in another substance known as a solvent. ... Polymer is a generic term used to describe a very long molecule consisting of structural units and repeating units connected by covalent chemical bonds. ... An electrode is a conductor used to make contact with a nonmetallic part of a circuit (e. ... Polymer is a generic term used to describe a very long molecule consisting of structural units and repeating units connected by covalent chemical bonds. ... Hydrogel is a network of polymer chains that are water-soluble, sometimes found as a colloidal gel in which water is the dispersion medium. ... Cellulose (C6H10O5)n is a long-chain polymer polysaccharide carbohydrate, of beta-glucose. ... An electrode is a conductor used to make contact with a nonmetallic part of a circuit (e. ... Polymer is a generic term used to describe a very long molecule consisting of structural units and repeating units connected by covalent chemical bonds. ... It has been suggested that Net flux be merged into this article or section. ... The word substrate can mean the following: In biochemistry, a substrate is a molecule which is acted upon by an enzyme. ...

Other lipid structures

Lipids can assume self-organized structures other than bilayers, depending on their concentration and type: Self-organization refers to a process in which the internal organization of a system, normally an open system, increases automatically without being guided or managed by an outside source. ...

• Micelles
• Monolayers
• Vesicles

In chemistry, a micelle (also micella, plural micellae) is an aggregate of surfactant molecules, usually of globular shape, but other geomtrical shapes are possible (ellipsoid, cyllinder, vesicules, lamellae etc. ... A monolayer is a single, closely packed layer of atoms or molecules [1]. A Langmuir monolayer is a one-molecule thick insoluble layer of an organic material spread onto an aqueous subphase. ... In cell biology, a vesicle is a relatively small and enclosed compartment, separated from the cytosol by at least one lipid bilayer. ...

See also

• Biological membrane
• Extracellular matrix
• OTG
• Phospholipid