ABSTRACT
Fatty acids have a long hydrocarbon chain with a terminal carboxylic acid group. Most fatty acids have an even number of carbon atoms in an unbranched chain. Saturated fatty acids have no double bonds between the carbon atoms, whereas mono- and polyunsaturated fatty acids have one or more double bonds. A fatty acid consists of a hydrocarbon chain and a terminal carboxylic acid group. Most fatty acids found in biology have an even number of carbon atoms arranged in an unbranched chain. The properties of fatty acids depend on their chain length and the number of double bonds. Shorter chain length fatty acids have lower melting temperatures than those with longer chains. Prostaglandins, and the structurally related molecules prostacyclins, thromboxanes and leukotrienes, are called eicosanoids because they contain 20 carbon atoms. These hormones are relatively short-lived and hence act locally near to their site of synthesis in the body.
