Waxes

Waxes are esters formed between a long-chain alcohol and a saturated fatty acid - chemically similar in principle to a triglyceride's ester bonds, but built from just one fatty acid and one long-chain alcohol rather than glycerol and three fatty acids. Because of their strongly hydrophobic character, waxes are used biologically as waterproof coatings: fur, feathers, fruit surfaces, leaves, skin and the exoskeletons of insects are all naturally waterproofed with a layer of wax. Lecithin, a related lipid, is widely used commercially as a food additive and dietary supplement. Certain waxes also have direct medical relevance - for example, wax D, found in the cell w …