1. Figure: 26.2
Title:
Table Approximate percentage of fatty acids in some common fats and oils.
Caption:
Fats are triacylglycerols that are solids or semisolids at room temperature. Oils are triacylglycerols that are liquid at room temperature.

2. Figure: UN
Title:
Glycerol, fatty acids, and a triacylglycerol.
Caption:
Triacylglycerols are compounds in which each of the three OH groups of glycerol has formed an ester with a fatty acid.

3. Figure: UN
Title:
A fat.
Caption:
Space-filling model of a triacylglycerol fat.

4. Figure: UN
Title:
An oil.
Caption:
Space-filling model of a triacylglycerol oil.

5. Figure: 26-00CO
Title:
Stick models embedded in electrostatic potential maps of stearic acid and linoleic acid.
Caption:
Stearic acid is a saturated fatty acid. Linoleic acid is an unsaturated fatty acid.

6. Figure: 26.1
Title:
Figure Anatomy of a lipid bilayer.
Caption:
Phosphoacylglycerols form membranes by arranging themselves in a lipid bilayer.

7. Figure: UN
Title:
The steroid ring system.
Caption:
All steroids contain a tetracyclic ring system.

8. The Catabolism of Fats

9. A kinase is an enzyme that puts a phosphoryl group on its substrate.
A dehydrogenase is an enzyme that oxidizes its substrate.
Dihydroxyacetone phosphate enters the glycolytic
pathway and is broken down further.

10. Mechanism for the conversion of glycerol-3-phosphate to dihydroxyacetone phosphate:

11. A fatty acid has to be activated before it can be metabolized:

12. acyl-CoA dehydrogenase enoyl-CoA hydratase
The fatty acyl-CoA is converted to acetyl-CoA via
b-oxidation:
acyl-CoA dehydrogenase
enoyl-CoA hydratase
3-L-hydroxyacyl-CoA dehydrogenase
b-ketoacyl-CoA thiolase

13. Figure: UN
Title:
Angular methyl groups on steroids.
Caption:
Substituents on the same side of the steroid ring system are b-substituents. Substituents on opposite sides of the steroid ring system are a-substituents.

14. Reaction mechanisms
Conjugate addition of water:
A retro-Claisen condensation:

15. Figure: UN
Title:
Cholesterol.
Caption:
Cholesterol is biosynthesized from squalene and is an important component of cell membranes.

16. Figure: UN
Title:
Cortisone and aldosterone.
Caption:
Cortisone is a glucocorticoid. Aldosterone is a mineralocorticoid.

17. Figure: UN
Title:
5a-Dihydrotestosterone and testosterone.
Caption:
5a-Dihydrotestosterone and testosterone are male sex hormones, known as androgens, and secreted by the testes.

18. Figure: UN
Title:
Estradiol, estrone, and progesterone.
Caption:
Estradiol and estrone are female sex hormones known as estrogens. Progesterone is the most important of a group of hormones called progestins.

19. Figure: UN
Title:
Cholic acid and chenodeoxycholic acid.
Caption:
Cholic acid and chenodeoxycholic acid are bile acids.

20. Figure: UN
Title:
Biosynthesis of lanosterol and cholesterol from squalene, I.
Caption:
The 2,3-double bond of squalene is epoxidized. Acid-catalyzed opening of the epoxide initiates a series of cyclizations resulting in the protosterol cation. Elimination of a C-9 proton from the cation initiates a series of 1,2-hydride and 1,2-methyl shifts, resulting in lanosterol.

21. Figure: UN
Title:
Biosynthesis of lanosterol and cholesterol from squalene, II.
Caption:
Converting lanosterol to cholesterol takes nineteen steps.

22. Figure: UN
Title:
Norethindrone and RU 486.
Caption:
Norethindrone and RU 486 are synthetic steroids used as oral contraceptives.