1. Steroids

3. Steroid A/B and B/C Rings Resemble Decalin

5. Methyl groups at C-10 and C-13 are “angular” methyl groups Steroid B/ C, and C/D rings are trans fused

6. Cholesterol

7. Structure of Cholesterol Cholesterol has the fundamental steroid skeleton modified as shown. HO CH 3 H H H

9. Biosynthesis of Cholesterol

10. Cholesterol HO CH 3 H H H

11. Vitamin D

12. Cholesterol HO CH 3 H H H Cholesterol is the precursor to vitamin D. Enzymes dehydrogenate cholesterol to introduce a second double bond in conjugation with the existing one. The product of this reaction is called 7-dehydrocholesterol.

13. 7-Dehydrocholesterol HO CH 3 H H Sunlight converts 7-dehydrocholesterol on the skin's surface to vitamin D 3.

14. Vitamin D 3 HO H CH 3 Insufficient sunlight can lead to a deficiency of vitamin D 3, interfering with Ca 2+ transport and bone development. Rickets can result.

15. Bile Acids

16. Cholesterol HO CH 3 H H H Oxidation in the liver degrades the cholesterol side chain. Cholic acid is the most abundant of the bile acids.

17. Cholic Acid Salts of cholic acid amides (bile salts) act as emulsifying agents to aid digestion. HOHOHOHO CH 3 H H H H OHOHOHOH HOHOHOHOOOH

18. Corticosteroids

19. Cholesterol HO H H H Enzymatic degradation of the side chain and oxidation of various positions on the steroid skeleton convert cholesterol to corticosteroids.

20. Cortisone Corticosteroids are involved in maintaining electrolyte levels, in the metabolism of carbohydrates, and in mediating the allergic response. O CH 3 H H H OHOHOHOH O O OHOHOHOH

21. Sex Hormones

22. Testosterone Testosterone is the main male sex hormone. O H H H H3CH3CH3CH3C H3CH3CH3CH3COH

23. Estradiol Estradiol is a female sex hormone involved in regulating the menstrual cycle and in reproduction. HO H H H H3CH3CH3CH3C OH

24. Progesterone Supresses ovulation during pregnancy. O H H H H3CH3CH3CH3C H3CH3CH3CH3CO

25. Synthetic Steroids

26. Recognizing Lipids: Structural Differences

27. Question Which of the triglycerides below is optically active? A)1 and 3B) 2 and 3 E) none C)3 onlyD) 1, 2, and 3

28. Question Misoprostol is classified as a A)terpene.B) wax. C)steroid.D) prostaglandin.

29. Question The backbone of cephalosporin P is classified as a A)prostaglandin.B) steroid. C)cholesterol.D) sesterpene.

30. Question Farnesol is classified as a A)monoterpene. B)sesquiterpene. C)diterpene. D)triterpene.