Lipids are membrane constituents and function as carbon stores

Lipids are membrane constituents and function as carbon stores

Lipids subdivide into glycerolipids, shingolipids, and steroids. Glycerolipids are fatty acid esters of glycerol (Fig. 15.1).Triacylglycerols (also called trig-lycerides) consist of a glycerol molecule that is esterified with three fatty acids. Whereas in animals triacylglycerols serve primarily as an energy store, they function in plants mainly as a carbon store in seeds, which are used by humans as vegetable oils. In polar glycerolipids, the glycerol is esterified with only two fatty acids, and a hydrophilic group is linked to the third -OH group. These polar lipids are the main constituents of membranes.