the Lipid (of Greek λίπος, lípos, „the fat “) is a collective term of natural substances, which differ in their chemical structure partly substantially, but due to its small polarity, i.e. the electrical charge is even in the moleculedistributed, in water (hydrophob) are insoluble. The materials separate however well in other organic solvents without Teilladungen (apolar) like gasoline, benzene, ether or chloroform (Lipophilie).
Lipide are divided in three groups:
- Fatty acids, triglycerides (again lower partable into fats and greases oils) and waxes, which have fatty acids (more exactly said hydrophilic fatty acid esters) as essential structure,
- Membranlipide (Phospholipide and Sphingolipide), are amphiphile fatty acid esters (that is, they have a polarand) and form a nonpolar part therefore in polar solvents thin skins (diaphragms) and
- Terpenoide, exact Steroide (derivatives of the Steran) and Carotinoide (derivatives of the Isopren).
Dependent on their ability to the soaping (by caustic solutions)the Lipide are classified also in soapable and unverseifbar. Soaping bar are accordingly the fatty acids, triglycerides, waxes and Membranlipide, unverseifbar the Terpenoide. A closer classification calls only triglycerides (fats and oils) Lipide, all different than Lipoide.
The biological functionsthe Lipide are just as various as their chemical structure. During fatty acids, triglycerides and waxes mainly as energy stores and building material, are Membranlipide serve, like the name already say, the basic modules of bio diaphragms. Terpenoide however serve for example as hormones,Plant dyes or antenna pigments (e.g. Chlorophyll). Many Lipide can be synthesized by the human body, but some must be taken up with the food. These are then called essential Lipide.
Table of contents
fatty acids, waxes, fats and greasesOil
this group of the Lipide are an important component of the food, since they are very high-energy (1 g fat contains 39 kJ = 9 kcal energy, of 1 g sugar only 4 kcal). Triglycerides are the most important storing off of the body forEnergy (sugars against it are stored in much smaller quantity in the form of Glykogen in the liver), it are a good insulation for cold in the skin, and there they protect also against injuries, since they have a pad function. All important organsby a fat coat are protected. In the nervous system they play an outstanding role in form of the myelin. As a function of the Myelinisierungsgrad the mammal brain up to the half of the dry weight (ten per cent of the fresh mass) from Lipiden exists, about which almost thirty per cent on thatMyelin been void (see also Dystrophie).
Satisfied fatty acids become, in which no double bonds occur, and insatiated fatty acids, which differentiated between one or more double bonds, which occurred always in cis - position and from each other isolated.An example of satisfied fatty acids is the butter acid, it is at the same time the shortest and contains four carbon atoms. Important representatives of the insatiated fatty acids are oleic acid (simply insatiated) and Arachidonsäure (several times insatiated). The contains more double bonds a fatty acid, the lowertheir melting point lies. Insatiated fatty acids can be synthesized by the animal organism only under restriction. One designation therefore all those fatty acids, those with the food to be taken up must as “essential fatty acids” (see below).
of triglycerides represent the largest group of the Lipide with a portion of 80% - 90%. Both fats and oils are three-fold ester (ester are Connections according to the pattern R 1 - CO-O-R 2, more in addition see there) the Glycerols and than triglycerides are designated. If triglycerides are isolated with the help of soaping a process specified, Glycerol develop and the appropriate salts of the fatty acids.
There are twoKinds mixed by triglycerides, simple and. With simple triglycerides the Seitenketten (thus the contained fatty acids) are identical, with mixed are different them. The cause for it that fat is liquid firmly and oil, lies in the substantially higher portion of insatiated fatty acidsin the oils.
If the Seitenketten R are different ¹ and R ³ in a molecule, then Chiralität step (that is, one would reflect the molecule, then a new molecule comes off, which by turn with the original to coincide are not set) and thus optical activity ( that is, that a solution incident polarized light turns ) can up.
of waxes are single esters of fatty acids, and differ as such from fats andOils, which are three-fold esters. Both the acid and the alcohol part of waxes have fatty acid remainders satisfied for a long time. Contrary to triglycerides are less „oilily “, in addition harder and more porous waxes.
Another definition (German society for fat science) sees waxesas material class, which is defined exclusively over its mechanical-physical characteristics. According to this definition are not kneadable, firmly to fragilly hard waxes with 20 °C, they exhibit a rough to fine-crystalline structure, coloured are translucent them to opak (obscurely), butglasslike, over 40 °C they melt few without decomposition, above the melting point are them easily liquid (a little viscously), exhibit a strongly temperature-dependent consistency and solubility and are polishingable under light pressure.
diaphragm screen end of Lipide
diaphragm screen end of Lipideare Lipide, which possess a hydrophilic and a hydrophoben part. The hydrophilic part arranges itself always to polar solvents such as water, the hydrophobe part arranges itself always away from them. Thus they know Mizellen (aggregates from amphiphilen molecules, itselfin a dispersion medium (usually water) spontaneously together-store) or Doppellipidschichten form. From this Doppellipidschichten all bio diaphragms are developed, which diaphragm screen end of Lipide one the Grundvorraussetzungen of all life makes.
of Phospholipide are beside proteins the main part of bio diaphragms. One differentiates it with respect to Phosphoglyzeride and Sphingomyeline. The structure of the Phosphogylzeride is similar from triglycerides, with the difference,that one of the groups is replaced by a phosphate alcohol. Sphingomyeline however differ from these by its Sphingosin - basic structure. The phosphorylierte alcohol of all Phospholipide is hydrophilic and „head “is called. The two fatty acids of the Phosphatidylgruppe (fatty acids, glycerinand phosphate) „tail “are called and are hydrophob. This opposite character leads to the formation of Doppellipidschichten, with which the hydrophobe part inward and the hydrophilic part outward show. The most important at the structurefrom bio diaphragms took part Phospholipide are the Phosphoglyzeride Phosphatidylcholin (also Lecithin), Phosphatidylethanolamin, Phosphatidylserin and in addition Sphingomyeline. Phosphatidylethanolamin and Phosphatidylserin are called also Kephaline. Particularly a group that important in the intrazellulären forwarding extrazelluärer signals (signal transduction)Phosphoglyzeride are the Phosphatidylinositole arising in different phosphorylation stages. As group of heads they possess a Phosphoinositol.
Sphingolipide are likewise components of cell membranes. Their basic structure consists of a fatty acid and a Sphingosin. It distinctive into the groups of the cerium amides, the Sphingomyeline and Glycolipide. Sphingolipide are in the nerve tissue, them play oneimportant role in the signal transmission and the interaction of individual cells.
Glycolipide are Sphingolipide with glykosidisch a coal hydrate bound to the 1-Hydroxyl-Gruppe of the Sphingosin - portion. They form frequently the exterior of biological diaphragms, whereby their coal hydrate portion upone presents to the cell membrane. It is assumed that these play a role in communication and interaction between individual cells. Glycolipide are differentiated with respect to Cerebroside , Ganglioside and Sulfatide.
Terpenoide are called connections, up Isopreneinheiten develop. To the Lipiden counting connections are the Steroide and the Carotinoide. Naturally occurring Steroide belongs to the Triterpenoid derivatives (Triterpenoid means it consists of 30 carbon atoms), since they all are biosynthesized on the basis of Squalen. Carotinoide become the Tetraterpenoid derivatives(40 carbon atoms) counted, they are derived from Lycopen .
Steroide all Steroide as essential structure a system from four, usually trans - connected carbon rings, three hexagonal and an five-angular. The most well-known representativethe Steroide is the Cholesterin ranking among the Sterinen. It is among other things also an essential component of all cell membranes with exception of the interior diaphragm of the Mitochondrien.
Bile acids, which are involved in the fat digesting, possess a hydrophoben and a hydrophilicPart, thus fats can encase and facilitate thus their absorption in the digestive tract. Sexualhormone are in the ovaries and the testicles produced Steroide, which steers the reproduction and the training of the secondary sex characteristics. The female sex hormones are Progesteron and OS troughs,male androgens (e.g. Testosteron and Androsteron).
Carotinoide are polymerization products of Isopren, which are manufactured exclusively in plants and as yellow to reddish coloring materials to function there. They consist usually of insatiated hydrocarbon chains and their oxidation products, and are composed of 8 Isopren units. They are differentiated with respect to Carotine and Xanthophylle. Thatmost well-known and most frequently occurring Carotinoid is well-known the β-carotin, also as Provitamin A. It is converted in the body into Retinol (Vitamin A), which plays an important role for the Sehvorgang.
during some Lipideby the human body in the fat metabolism to be manufactured can be taken up, must others with the food. One calls these essential Lipide. In addition the essential fatty acids and the fat-soluble Vitamine A, D, E and K belong.
cannot manufacture essential fatty acids double bonds in the hydrocarbon chain of a fatty acid, which are distant from the group of carboxyls more than 9 C-atoms, independently. These are however of important importance and must therefore over the food be taken up. Thereforethey are called essential. Among the representatives of the essential Omega-3-Fettsäuren rank the Linolensäure, Eicosapentaensäure and Docosahexaensäure. Essential Omega-6-Fettsäuren is the Linolsäure and the Arachidonsäure, from that the Eikosanoide, the important Gewebshormone and Mediatoren in the bodyare, to be synthesized.Omega-9-Fettsäuren are not essential, since they can be synthesized from Omega-3 and Omega-6-Fettsäuren. Possible sources of food for Omega-3 and Omega-6-fettsäuren are fish, flax seeds, Sojaöl, Hanföl, cure until cores or Walnüsse.
Essential fatty acids play an important role during many metabolic processes, andthere are references that lack or unequal weights are in the admission of the essential fatty acids a cause of numerous diseases.
the fat-soluble Vitamine are
- Vitamin A, a Terpen, an important role on the one hand with the Sehvorgang,on the other hand for growth, function and structure of skin and mucous membranes , Vitamin
- D, responsibly for the regulation of the calcium and phosphorus concentrations in the blood and thus for the bone stability of crucial importance Vitamin
- E, plays a Terpenoid with anti-more oxidativeEffect and
- Vitamin K, a Terpenoid, which participates in the blood clotting.
- George Löffler, Petro E. Petrides: Biochemistry and Pathobiochemie. Springer, Berlin 2003, ISBN 3540422951
- Florian horn, Isabelle Moc, Nadine cutter: Biochemistry of humans.Thieme, Stuttgart2005, ISBN 3131308834
- Charles E. Mortimer, Ulrich Mueller: Chemistry. Thieme, Stuttgart 2003, ISBN 3134843080
- Technology OF of Lipids
- Genomics OF Lipid Associated Disorders the Web on the left of http://www.medizinfo.de/kardio/lipide/blutfette.htm animation on
- English European Federation for - outstanding side of the technical ones University of Graz, and. A. with an abundance of Lipid metabolic pathways
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