1. Commonly called “Fats”
Lipids
Commonly called “Fats”

2. Lipids
Lipids are oils, fats, waxes, cholesterol, and similar molecules that do not dissolve in water
Composed of glycerol and fatty acids

3. Glycerol
Always has 3 carbon atoms and 3 hydroxyl (OH)groups

4. Fatty Acids Many different kinds
They range in size from having 4 Carbons to 24 Carbons
On one end of the fatty acid is a Carboxyl group (COOH or COO-, acts as an acid….recall amino acids)
The rest of the fatty acid is pure hydrocarbon (C & H only…recall that these are non-polar)

5. Fatty Acids Can be saturated (all single bonds) or unsaturated
Carboxyl group
Puts a kink in the fatty acid

6. Triglyceride (tri-gliss-er-ide)
Consists of a molecule of glycerol joined to 3(tri) fatty acids
Joined by the same dehydration condensation reaction as we saw in Amino acids and carbohydrates

7. Triglyceride
Dehydration condensation – joining of glycerol and 3 fatty acid to make a triglyceride

8. Triglyceride ***Overall, fats are not attracted to water
Slightly polar near oxygens
NON POLAR
Since hydrocarbons are non-polar, ENTIRE molecule is non-polar except for the slightly polar area around the oxygen
***Overall, fats are not attracted to water

9. Phospholipid Much like triglycerides except…
In place of a 3rd fatty acid there is a phosphate group and some other polar group
This results in a molecule with a dual nature!!!

10. Phospholipid This results in a molecule with a dual nature!!!
Hydrophobic the hydrocarbons of the fatty acid are nonpolar
Hydrophilic (polar- phosphate and other group)

11. Dual nature of phospholipid
It is this dual nature of the phospholipid molecule that allows it to form cell membranes…
We will simplify this molecule and draw it like this:
POLAR

12. Phospholipid Bilayer (membrane of Cell)

13. Steroid Nucleus – another lipid
Consists of Four interlocking rings of carbon atoms with numerous hydrogen atoms attached
Steroid Nucleus is the core of a wide variety of molecules, including hormones

14. Waxes
Provide protective coatings for various plants and animal tissues and for bees to make honeycombs
Formed by dehydration condensation of a long chain alcohol (hydrocarbon + OH) joined to a long chain fatty acid