Common Biological Fatty Acids Number of Carbons Common Name Systematic Name Symbol Structure Satrated fatty acids 12 Lauric acid Dodecanoic acid 120 CH(CH2)COOH 14 Myristic acid Tetradecanoic acid 140 CH3(CH2)COOH 16 Palmitic acid Hexadecanoic acid 160 CH:(CH2)COOH 18 Stearic acid Octadecanoic acid 180 CH3(CH2)COOH 20 Arachidic acid Eicosanoic acid 20:0 CH(CH2)COOH 2 Bchenic acid Docosanoic acid 220 CH3(CH2)2COOH 24 Lignoceric acid Tetracosanoic acid 240 CH(CH2)COOH Unsaturated fatty acids (all double bonds are cs) 16 Palmitolcic acid 9-Hexadecenoic acid 161 CH(CH)CH-=CH(CH)-COOH 18 Oleic acid 9-Octadecenoic acid 18:1 CH(CH )CH-CH(CH)-COOH 18 Linoleic acid 9.12-Octadecadienoic acid 18:2 CH:(CH2)(CH=CHCH2)2(CH2)COOH 18 a-Linolenic acid 9.12.15-Octadecatrienoic acid 18:3 CHCH(CH=CHCH)(CH2).COOH 18 y-Linolenic acid 6.9.12-Octadecatrienoic add 18:3 CH(CH2)a(CH=CHCH)(CH2)COOH 20 Arachidonic acid 5,8.11,14-Eioosatetracnoic acid 20:4 CH:(CH2)(CH=CHCH2)(CH2)2COOH 24 Nervonic acid 15-Tetracosenoic acid 2尘1 CH(CH)CH=CH(CH2)COOH