Fats Also known as lipids

Fats and oils are made up of triglycerides

Synthesis Saturated fatty acid Glycerol Unsaturated fatty acid Fats with multiple double C=C bonds are called polyunsaturated fats

Triglyceride synthesis Glycerol + The synthesis of a triglyceride produces 3 water molecules

Shown step by step . . . . H2O monoglyceride OH O Fatty acid 1 HO O OH ycero l OH O Fatty acid 1 HO Gl ycero l O OH Fatty acid 1 Fatty acid 2 HO H2O diglyceride O O OH O OH Gl ycero l diglyceride HO Fatty acid 3 H2O triglyceride This process is reversed in digestion with the help of bile & lipase

Triglycerides are held together by ESTER LINKAGES

Saturated and unsaturated fatty acids If every carbon in the chain has all the hydrogen atoms it can bond to, then the fatty acid is said to be saturated. The middle fatty acid has two carbons that are one hydrogen short. That's because there's a double bond between those carbons. This fatty acid is said to be monounsaturated. The bottom fatty acid have two places where carbons don't have all the hydrogen atoms. This is polyunsaturated. The polyunsaturated fatty acids are said to be healthier.

Unsaturated fatty acids are bent Extras There are greater Van der Waals forces between straight chain fatty acids (and longer fatty acid chains) so they tend to be fats rather than oils. You do not need to know the names of different fatty acids but you should be able to distinguish between saturated and unsaturated chains. Unsaturated fatty acids are bent Fats provide insulation, buoyancy and can be a source of water e.g. camels

Difficulty drawing triglycerides? NB These do not show where the water molecules come from or the ester linkages

State three functions of lipids. Lipids can be used for energy storage in the form of fat in humans and oil in plants. Lipids can be used as heat insulation as fat under the skin reduces heat loss.  Lipids allow buoyancy as they are less dense than water and so animals can float in water.