1. Lipids!

2. Examples Examples fats oils waxes hormones sex hormones
testosterone (male)
estrogen (female)

3. Lipids: the concentrated energy molecule
Function:
1. energy storage (in C-H bond)
very concentrated
twice the energy as carbohydrates
2. cell membrane
3. cushions organs
4. insulates body
think whale blubber

4. A little more on lipids…
Structure: composed of C, H, O
long hydrocarbon chains (H-C)
“Family groups”
fats
phospholipids
steroids
Lipids ≠ Polymers
BIG molecules of smaller subunits; NOT a continuing chain

5. 1. Fats
Structure: glycerol (3C alcohol) + fatty acid **fatty acid = long HC “tail” & carboxyl (COOH) “head”**
enzyme
H2O

6. Triglycerides – 3 fatty acids + glycerol Example: Triacylglycerol
Building Fats
Triglycerides – 3 fatty acids + glycerol
Example: Triacylglycerol
C – O – C bond = Ester Linkage via dehydration synthesis

7. ALL carbons bonded to 4 atoms Carbons NOT bonded 4 atoms
Saturated vs. Unsaturated Fats
Saturated
ALL carbons bonded to 4 atoms
Unsaturated
Carbons NOT bonded 4 atoms
Single bonds
Double bonds
Straight chain
Kinks

8. Saturated
Unsaturated 

9. Amphipathic - fats with polar and nonpolar regions
2. Phospholipids
Structure: glycerol + 2 fatty acids + PO4
** PO4 = negatively charged **
Review: tail – polar/nonpolar?
PO4 – polar/nonpolar?
Amphipathic - fats with polar and nonpolar regions
“attracted to water”
“repelled by water”

10. Significance of phospholipids
In water:
can self-assemble into “bubbles” (micelles)
form phospholipid bilayer
cell evolution!
creates barrier → form cell membranes!

11. 3. Steroids Structure: 4 fused C rings + functional groups
** different structure = ? **
Examples: cholesterol, sex hormones
cholesterol

12. Role of Cholesterol Component in animal cell membranes
Precursor to other steroids (Ex: sex hormones)