Lipids are a class of biological molecules defined by low solubility in water and high solubility in nonpolar solvents. As molecules that are largely hydrocarbon in nature, lipids represent highly reduced forms of carbon and, upon oxidation in metabolism, yield large amounts of energy. Lipids are thus the molecules of choice for metabolic energy storage. What are the structure, chemistry, and biological function of lipids? | Chapter 8 Lipids to accompany Biochemistry, 2/e by Reginald Garrett and Charles Grisham All rights reserved. Requests for permission to make copies of any part of the work should be mailed to: Permissions Department, Harcourt Brace & Company, 6277 Sea Harbor Drive, Orlando, Florida 32887-6777 Outline Fatty Acids Triacylglycerols Glycerophospholipids Sphingolipids Waxes Terpenes Steroids Classes of Lipids All biological lipids are amphipathic Fatty acids Triacylglycerols Glycerophospholipids Sphingolipids Waxes Isoprene-based lipids (including steroids) Fatty acids Know the common names and structures for fatty acids up to 20 carbons long Saturated Lauric acid (12 C) Myristic acid (14 C) Palmitic acid (16 C) Stearic acid (18 C) Arachidic acid (20 C) Fatty acids - II Unsaturated fatty acids Palmitoleic acid (16:1) Oleic acid (18:1) Linoleic acid (18:2) -Linolenic acid (18:3) -Linolenic acid (18:3) Arachidonic acid (20:4) Fatty acids - III Structural consequences of unsaturation Saturated chains pack tightly and form more rigid, organized aggregates (., membranes) Unsaturated chains bend and pack in a less ordered way, with greater potential for motion Triacylglycerols Also called triglycerides A major energy source for many organisms Why? Most reduced form of carbon in nature No solvation needed Efficient packing Triacylglycerols - II Other advantages accrue to users of triacylglycerols Insulation Energy without nitrogen Metabolic water Glycerophospholipids Glycerophospholipids are phospholipids but not necessarily vice versa Know the names and structures in Figure Understand the prochirality of glycerol Remember that, if phospholipid contains unsaturation, it is at the 2-position Ether Glycerophospholipids An ether instead of an acyl group at C-1 See Figure Plasmalogens are ether glycerophospholipids in which the alkyl chain is unsaturated Ether Glycerophospholipids Platelet activating factor (PAF) is an ether . | Chapter 8 Lipids to accompany Biochemistry, 2/e by Reginald Garrett and Charles Grisham All rights reserved. Requests for permission to make copies of any part of the work should be mailed to: Permissions Department, Harcourt Brace & Company, 6277 Sea Harbor Drive, Orlando, Florida 32887-6777 Outline Fatty Acids Triacylglycerols Glycerophospholipids Sphingolipids Waxes Terpenes Steroids Classes of Lipids All biological lipids are amphipathic Fatty acids Triacylglycerols Glycerophospholipids Sphingolipids Waxes Isoprene-based lipids (including steroids) Fatty acids Know the common names and structures for fatty acids up to 20 carbons long Saturated Lauric acid (12 C) Myristic acid (14 C) Palmitic acid (16 C) Stearic acid (18 C) Arachidic acid (20 C) Fatty acids - II Unsaturated fatty acids Palmitoleic acid (16:1) Oleic acid (18:1) Linoleic acid (18:2) -Linolenic acid (18:3) -Linolenic acid (18:3) Arachidonic acid (20:4) Fatty acids - III Structural .
