LIPIDS Lipids are a family of organic compounds These lipids are found in cheese butter oil whole milk fried foods and also in some red meats etc It is synthesized in the liver of the human body It is mostly insoluble in water Composed of fats and oils lipids are molecules that yield high energy and have a chemical composition mainly of carbon hydrogen and oxygen which a is framework for the function and structure of living cells is called lipids The three main types of lipids are triacylglycerols phospholipids and sterols Lipids Definition Lipids are organic compounds that contain hydrogen carbon and oxygen atoms which form the framework for the structure and function of living cells Functions of lipids They help with moving and storing energy absorbing vitamins and making hormones Storing and providing energy Chemical messengers Cholesterol formation Regulating body temperature Formation of Prostaglandin and its role in inflammation Membrane lipid layer formation Properties of Lipids Lipids are oily or greasy nonpolar molecules stored in the adipose tissue of the body Lipids are a heterogeneous group of compounds mainly composed of hydrocarbon chains Lipids are energy rich organic molecules which provide energy for different life processes Lipids are a class of compounds characterised by their solubility in nonpolar solvents and insolubility in water Lipids are significant in biological systems as they form a mechanical barrier dividing a cell from the external environment known as the cell membrane 1 Simple Lipids Esters of fatty acids with various alcohols Fats Esters of fatty acids with glycerol Oils are fats in the liquid state Waxes Esters of fatty acids with higher molecular weight monohydric alcohols 2 Complex Lipids Esters of fatty acids containing groups in addition to alcohol and fatty acid 1 Phospholipids 2 Glycolipids glycosphingolipids 3 lipoproteins 4 Other complex lipids 1 Glycerophospholipids Alcohol present in these lipids is glycerol The diester of glycerophosphoric acid is the most abundant one in which phosphoric acid is also ester linked to nitrogenous and non nitrogenous alcohol Examples Phosphatidic acid Lecithin Cephalins Plasmalogens 2 Sphingophospholipids These include sphingomyelins which contain the alcohol called sphingosine a fatty acid phosphoric acid and a nitrogenous base Sphingomyelins are the only lipids that contain both sphingosine and H3PO4 1 Phospholipids These are lipids containing in addition to fatty acids and alcohol phosphate group nitrogen containing bases other substituents It is subdivided into two groups 1 glycerophospholipids the alcohol is glycerol 2 sphingophospholipids the alcohol is sphingosine 2 Glycolipids glycosphingolipids Lipids containing a fatty acid sphingosine and carbohydrate 3 lipoproteins Lipoproteins are round particles made of fat lipids and proteins that travel in your bloodstream to cells throughout your body Cholesterol and triglycerides are two types of lipids found in lipoproteins 4 Other complex lipids Lipids such as sulfolipids and amino lipids Lipoproteins may also be placed in this category 3 Derived Lipids The derivatives of simple and conjugated lipids is called derived lipids These include fatty acids glycerol steroids other alcohols fatty aldehydes and ketone bodies hydrocarbons lipid soluble vitamins and hormones Because they are uncharged acylglycerols glycerides cholesterol and cholesteryl esters are termed neutral lipids 4 miscellaneous lipids The large number of compounds possessing the charcteristics of lipids Example squalene terpenes hydrocarbons carotenoids