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 Phospholipids Waxes Steroids
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 Making a lipid The other key parts to a lipid are fatty acids
Long carbon chains
Car
Carbon Chain
Carboxyl
Group
COOH

6. Lipids 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
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)

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