lipids definition of lipids in the Free Online Encyclopedia.

lipids, a broad class of organic products found in living systems. Most are insoluble in water but soluble in nonpolar solvents. The definition excludes the mineral oils and other petroleum products obtained from fossil material. Major classes of lipids include the fatty acids fatty acid, any of the organic carboxylic acids present in fats and oils as esters of glycerol . Molecular weights of fatty acids vary over a wide range. The carbon skeleton of any fatty acid is unbranched. Some fatty acids are saturated, i.e.
..... Click the link for more information. , the glycerol-derived lipids (including the fats and oils fats and oils, group of organic substances that form an important part of the diet and also are useful in many industries. The fats are usually solid, the oils generally liquid at ordinary room temperatures.
..... Click the link for more information. and the phospholipids phospholipid (fŏs'fōlĭp`ĭd)
..... Click the link for more information. ), the sphingosine-derived lipids (including the ceramides, cerebrosides, gangliosides, and sphingomyelins), the steroids steroids, class of lipids having a particular molecular ring structure called the cyclopentanoperhydro-phenanthrene ring system. Steroids differ from one another in the structure of various side chains and additional rings.
..... Click the link for more information. and their derivatives, the terpenes and their derivatives, certain aromatic compounds, and long-chain alcohols and waxes wax, substance secreted by glands on the abdomen of the bee and known commonly as beeswax; also various substances resembling beeswax. Waxes are mixtures comprising chiefly esters of monohydroxy alcohols, besides other esters and free fatty acids, free alcohols, and
..... Click the link for more information. . In living organisms lipids serve as the basis of cell cell, in biology, the unit of structure and function of which all plants and animals are composed. The cell is the smallest unit in the living organism that is capable of integrating the essential life processes. There are many unicellular organisms, e.g.
..... Click the link for more information. membranes and as a form of fuel storage. Often lipids are found conjugated with proteins or carbohydrates, and the resulting substances are known as lipoproteins lipoprotein (lĭp'əprō`tēn)
..... Click the link for more information. and lipopolysaccharides. The fat-soluble vitamins vitamin, group of organic substances that are required in the diet of humans and animals for normal growth, maintenance of life, and normal reproduction. Vitamins act as catalysts; very often either the vitamins themselves are coenzymes , or they form integral parts
..... Click the link for more information. can be classified as lipids. Liposomes liposome (lī`pəsōm', lĭp`ə–)
..... Click the link for more information. are spherical vesicles formed by mixing lipids with water or water solutions. They have found applications in the oral administration of some drugs (e.g., insulin and some cancer drugs), since they retain their integrity until they are broken down by the lipases lipase (lī`pās), any enzyme capable of degrading lipid molecules.
..... Click the link for more information. in the stomach and small intestine.