Lipids

1. Lipids

2. Lipids • Lipids • Molecules made up of mostly carbon and hydrogen atoms (and some oxygen atoms too) • Used for storing energy • Important part of cell membranes

3. Lipids • 4 classes • Triglycerides • 1 glycerol molecule, 3 fatty acid molecules • Energy source, insulation • Phospholipids • 1 glycerol molecule, 1 phosphate group, 2 fatty acid molecules • Cell membrane barrier • Waxes • 1 long fatty acid chain, 1 long alcohol chain • Waterproof protective coating • Steroids • 4 fused carbon rings with functional groups attached • Hormones like testosterone, cholesterol, estrogen

4. Lipids • Making a lipid: • The first key part to a lipid is a glycerol • Glycerol serves as the “backbone” of the lipid

5. Lipids Car Carbon Chain Carboxyl Group COOH • Making a lipid • The other key parts to a lipid are fatty acids • Long carbon chains

6. Lipids • Unsaturated • One or more double bonds in the carbon chain • There could be more hydrogen • Generally considered “better” for you • Liquid at room temperature • Kinked (not straight) • 2 kinds of fatty acids: • Saturated • All single bonds in the carbon chain • There are the maximum possible number of hydrogen • Generally considered “bad” for you • Solid at room temperature • Straight

7. Lipids • Making a lipid • So how do the glycerol and fatty acids come together? • Dehydration synthesis…

8. Lipids Dehydration synthesis in a triglyceride

9. Lipids Dehydration synthesis in a triglyceride

10. Lipids • Examples of lipids • Meat fat • Oil • Waxes • Butter • Grease • Mayo

11. Lipids • Tests to run: • The water solubility test • Lipids do not mix in water – non lipids do • This is because lipids are hydrophobic (as opposed to hydrophilic) • The brown paper bag test • If you put a substance on a paper bag and the bag dried well over time, the substance was a non-lipid. If the bag never looks dry and light can get through it, the substance was a lipid