Lipids are essential components of all living organisms. They are water insoluble organic compounds.
Compounds that are not degraded by alkaline or acid hydrolysis or that upon hydrolysis yield only derived lipids, i.e., substances soluble in fat solvents, or derived lipids plus glycerol are all considered simple lipids.
Simple Lipids or homolipids classifications:
*Fatty acids
*Neutral fats (mono-, di- and triacyl glycerols)
*Wax (Sterol ester, Nonsterol ester)
Neutral lipids can be surrounded by a hydrophilic shell composed of phospholipids or serum lipoproteins, they can be encompassed by detergents and phospholipids (intestinal micelles), or they can be bound to amphipathic proteins (transfer proteins).
Fatty acids are stored as neutral lipids called triaclyglycerols (TGs). Triaclyglycerols are composed of 3 fatty acyl residues esterified to a glycerol (3- carbon sugar alcohol). Triaclyglycerols are very hydrophobic, and are stored in cells in an anhydrous form (e.g in fat droplets).
The neutral fat polymer is called a triglyceride. Dehydration synthesis bonds 3 fatty acid chains to the glycerol molecule and removes 3 water molecules. Just like the other classes of organic compounds, triglycerides are reduced to glycerols and fatty acids again through hydrolysis.
Neutral fats
