Biochemistry 2280A Lecture Notes - Lecture 6: Caveolae, Integrin, Bacteriorhodopsin
Document Summary
All cells are enclosed by a membrane composed of lipids, proteins and carbohydrates. Eukaryotic cells also have internal membranes that divide the cell into different compartments (fig 11-3, p. 360). Biological membranes are based on certain types of lipid molecules. Lipids are biological molecules that have little or no solubility in water, but are soluble in organic solvents. In addition to being structural components of biological membranes, lipids also function as energy storage molecules (see topic 12), enzyme cofactors, signalling molecules, and pigments. Structurally, lipids may be divided into several different classes, some of which are described below (see panel 2-4, p. 72-73). Fatty acids are hydrocarbon chains ending in a carboxylic acid group (movie 2. 2). Fatty acids usually contain an even number of carbon atoms, and range in length from 4 to 36 carbons. If the hydrocarbon chain has no double bonds, it is called saturated. If it has one double bond, it is called monounsaturated.