Lipids: Fats Oils

1. Lipids: Fats & Oils

2. 2006-2007 Lipids

3. Lipids Lipids are composed of C, H, O are esters of long-chain fatty acids and alcohols Diverse group fats Fixed oils Waxes

4. Fat and Fixed oil Structure: glycerol (3C alcohol) + fatty acid Note functional group = carboxyl Note functional group = carboxyl

5. Building Fats Triacylglycerol 3 fatty acids linked to glycerol ester linkage = between OH & COOH

6. Dehydration synthesis

7. Structure of Fatty Acids The �tail� of a fatty acid is a long hydrocarbon chain, making it hydrophobic. The �head� of the molecule is a carboxyl group which is hydrophilic. Fatty acids are the main component of soap, where their tails are soluble in oily dirt and their heads are soluble in water to emulsify and wash away the oily dirt. However, when the head end is attached to glycerol to form a fat, that whole molecule is hydrophobic.

8. Saturated fats All C bonded to H No C=C double bonds long, straight chain most animal fats solid at room temp. contributes to cardiovascular disease (atherosclerosis) = plaque deposits

9. Unsaturated fats C=C double bonds in the fatty acids plant & fish fats vegetable oils liquid at room temperature the kinks made by doublebonded C prevent the molecules from packing tightly together

10. Saturated vs. unsaturated

11. In unsaturated fatty acids, there are two ways the pieces of the hydrocarbon tail can be arranged around a C=C double bond (cis and trans). In cis bonds, the two pieces of the carbon chain on either side of the double bond are either both �up� or both �down,� such that both are on the same side of the molecule. In trans bonds, the two pieces of the molecule are on opposite sides of the double bond, that is, one �up� and one �down� across from each other.