1. Lipids Greek: lipos, fat Chemical diverse set of molecules that are insoluble in water

2. Other Lipid Characteristics Not polymers Aggregation — e.g. bilayers (membranes) Greatest structural variation of major biomolecules

3. Major Classes of Lipids

4. Functions of Lipids Biological Membranes (bilayers) Energy Stores Signaling –Intracellular –Intercellular

5. Fatty Acids (Simplest Lipids) Amphiphilic/Amphipathic Usually esterified form in nature Saturated and unsaturated Usually even number of carbon atoms

6. SaturatedUnsaturated Fatty Acids

7. Some C 18 Fatty Acids (cis double bonds)

8. Omega naming 987654321ω987654321ω ω-3 fatty acidω-6 fatty acid

9. Common Biological Fatty Acids

11. Triacylglycerols Constitute ~90% of Dietary Lipid Major form of Metabolic Energy Storage in Humans Simple: all the same fatty acid Mixed: different fatty acids

12. Page 248 1-Palmitoleoyl-2-linoleoyl-3-stearoylglycerol

13. Importance of Triacylglycerols (Adipocytes and Adipose Tissue) Energy Resevoirs –Less oxidized than carbohydrates and amino acids –Anhydrous versus hydrated glycogen –6x energy yield versus glycogen –2-3 month energy supply versus <1 day for glycogen Thermal Insulation Not components of biological membranes

14. Figure 9-2 Adipocytes (Scanning Electron Microscope)

15. Glycerophospholipids ( Amphiphilic) C16 or C18 Saturated C18 or C20 UNsaturated

16. Figure 9-3a Glycerol-3-phosphate

17. C16-18 C18-20

18. Glycerophospholipids ( Amphiphilic) Non- Polar Tail Polar Head

19. Figure 9-4 1-Stearoyl-2-oleoyl- 3-phophatidyl choline Non- Polar Tail Polar Head

20. Figure 9-5 Action of Phospholipases ( Determination of Structure)

21. Figure 9-6 Model of Phospholipase A 2 and a Glycerophospholipid

22. Action of Phospholipases (Formation of Signal Molecules) Lysophosphatidic Acid Blood Platelets — Wound Repair

23. Action of Phospholipases (Formation of Signal Molecules) Diacylglycerol Signaling Cascade

24. Sphingolipids Sphingosine Head group Fatty acid

25. Glycolipids

26. Figure 9-7a A Sphingomyelin

27. Figure 9-8 Myelinated Nerve Fiber (Electron Microscopy)

28. Sphingolipids and Phospholipids have similar physiochemical properties

29. Sphingolipids (Cerebrosides) Non-ionic Membrane Lipid

30. Sphingolipids (Gangliosides)

31. Figure 9-9b Ganglioside G M2

32. Importance of Gangliosides Cell Surface Receptors –Hormones –Toxins Determinants of Cell-Cell Recognition Disorders of Ganglioside Breakdown –Tay-Sachs disease – fatal neurological breakdown

33. Page 254 Steroids (Steroid Core Structure)

34. Cholesterol

35. Figure 9-10a Cholesterol Numbering

36. Figure 9-10b Cholesterol Structure

37. Page 254 Cholesterol Ester

38. Importance of Cholesterol Major Component of Animal Plasma Membranes (and to a lesser extent organelle membranes) Precursor of Steroid Hormones

39. Page 257 Isoprenoids (Isoprenoid Precursor)

40. Page 257 Isoprenoid Example (Coenzyme Q)

41. Lipid Summary Sparingly soluble in water Not polymers – aggregates Diverse Functions –Biological membranes –Energy stores –Signaling molecules