Biochemistry

Simple lipids are substances whose molecules are composed of residues of fatty acids (or aldehydes') and alcohols. These include neutral fats (triacylglycerols, other glycerols) and waxes. This group also includes vitamins A and D esters with higher fatty acids. Complex lipids, in addition to higher fatty acids and alcohols, contain derivatives of phosphoric acid (phospholipids), sugar residues (glycolipids), nitrogenous compounds (choline, colamine, serine). Important for the body are derivatives of lipids. They are similar in structure and physicochemical properties, are closely related in the structure of cells and metabolic processes. These include saturated and unsaturated fatty acids, mono- and diacylglycerols, higher alcohols, pigments (carotenes), fat-soluble vitamins, etc. 6.2 SIMPLE LIPIDS If one hydroxyl group is esterified with fatty acid in glycerol (glycerol), then monoacylglycerol is formed , if two, then diacylglycerol, if three, then triacylglycerol. CH 2 -OH CH-OH CH 2 -OH ch 2 - o - c - r 1 CH — oh CH 2 - OH C H 2 -O-C-R i z p CH-O-C-Rz CH 2 -OH CH2-O-C-R1 CH-O-C-Rj ,9 CH 2 - 0- c- R 3 Glycerol Monoacylglycerol Diacylglycerol Triacylglycerol The bulk of natural fats are triacylglycerols . They include saturated and unsaturated fatty acids (palmitic, stearic and oleic acids are most common). If triacyl glycerol contains one fatty acid , then it is called simple (for example, tristearin, tripalmitin), if acid radicals belong to different fatty acids , then mixed triglycerols are formed, their names depend on the incoming fatty acids (for example, l-palmito-2- stearino-3-olein). Waxes are esters of higher fatty acids and higher monohydric or dihydric alcohols containing from 20 to 70 carbon atoms. This group of fats serves mainly a protective role. Natural waxes (beeswax, lanolin, spermaceti), in addition to esters, include free fatty acids, alcohols, etc. They are part of the fat that covers the skin of a person. 1 26