A.1.6 Outline the variation in the molecular structure of fatty acids

Fatty acids have 3 parts to their structure: '-COOH' carboxyl group, '-CH3' methyl group (or omega group) and the hydrocarbon chain in the middle. Saturated Vs Unsaturated: A saturated fatty acid means that every carbon in the hydrocarbon chain is attached to as many hydrogens as possible whereas in contrast in an unsaturated fatty acid there is one or more double bonds in the hydrocarbon chain because some carbons are not attached to the maximum number of hydrogens possible. Monounsaturated Vs Polyunsaturated: A monounsaturated fatty acid is one which contains only one double bond, whereas a polyunsaturated fatty acid contains two or more double bonds Cis Vs Trans unsaturated: In a Cis unsaturated fatty acid the hydrogens (attached to the carbons either side of the double bond) are on the 'same side' so far as the diagram goes. In a Trans unsaturated fatty acid the hydrogens (attached to the carbons either side of the double bond) are on 'opposite sides' so far as the diagram goes. An Omega-3 fatty acid is an example of a Cis-polyunsaturated fatty acid that the IB wants you to be familiar with. It is named as such because the first double bond is on the third carbon if you count from the omega group (methyl group)