1. Lipids

2. Lipids Biological compound soluble in non-polar solvent
Chemically heterogeneous: Simple or Complex
Simple Lipid: alcohol + one or more fatty acids
Complex lipid: alcohol + fatty acid + something else

3. Classification of Lipids

4. Fatty Acids Linear Molecules 10-20 carbons in length
Even number of carbons
No other functional groups but carboxyl
Sometimes alkene groups C=C
Saturated vs. unsaturated

6. Water Solubility
Hydrophobic part of molecule dominates: very insoluble in water
Forms micelles in water

7. * * * * * * * *

8. saturated Fatty Acids Fatty Acid # of Carbons # of C=C lauric 12
myristic 14
palmitic 16
stearic 18

9. Unsaturated Fatty Acids
# of Carbons
# of C=C
oleic 18 1
linoleic 2
linolenic 3
arachadonic 20 4

10. Properties of Fats and Oils
Triacylglycerols in natural fats and oils are nonpolar, hydrophobic molecules with no ionic charges.
Oil: A mixture of triacylglycerols that is liquid because it contains a high proportion of unsaturated fatty acids.
Fat: A mixture of triacylglycerols that is solid because it contains a high proportion of saturated fatty acids.

11. The hydrocarbon chains in saturated acids are flexible and uniform in shape, allowing them to nestle together. By contrast, the carbon chains in unsaturated acids have rigid kinks wherever they contain cis double bonds. The kinks make it difficult for such chains to fit next to each other in the orderly fashion necessary to form a solid.

12. Melting Points Increases with size (lesser effect)
Decreases with unsaturation (greater effect)

13. Cis vs Trans Fatty Acids
Cis fatty acids occur naturally
Trans fatty acids occur during hydrogenation reactions

14. Alternate View of Fatty Acids

15. Triglycerides: Fats and Oils
Glycerol + 3 Fatty Acids
Connected by ester bonds

16. Triglyceride

17. Fat or Oil
Depends on melting point- solid or liquid at room temperature
Depends mostly on degree of unsaturation
Animal Fats more saturated, plant oils more unsaturated

18. Dietary Fatty Acids Saturated fats associated with Heart Disease
Promotes higher levels of blood cholesterol
Animal fats also contain cholesterol, plants have no cholesterol

19. Chemical Properties of Triglycerides
1. Reaction with I2
Used to quantitate unsaturation in fats
Product is colorless, I2 is colored
Iodine number = grams I2 reacting with 100 g fat

20. 2. Hydrolysis of Ester: catalyzed by acid or enzyme

21. 3. Saponification with NaOH

22. Saponification Reaction produces Soaps
Hydrophilic and hydrophobic regions
Hydrophobic dissolved in oils
Hydrophilic stays on the surface
Insoluble salts form with hard water
Sodium stearate
Sodium dodecyl sulfate

23. 4. Hydrogenation Reacts with alkene Partial or complete hydrogenation
Produces more saturated fat
Changes plant oil to margarine

24. Review of Chemical Reactions

25. Artificial Fats Simpless: micro-particles of proteins
Smooth cream texture
Not heat stable
1.3 Cal/gram vs. 9 Cal/gram for fats
Olestra: polymer of sucrose and fatty acids
Not digestable
Taste and texture of fats
Causes loss of fat soluble vitamins and other side effects

26. Waxes Long chain fatty acid + long chain fatty alcohol
Myristyl palmitate

27. Wax Block Diagram

28. Phosphoglycerides Glycerol, 2 fatty acids, phosphate + another alcohol

29. Phosphatidic acid

30. Alcohols used in phosphoglycerides
choline
serine
ethanolamine

31. Phosphatidyl Choline (lecithin)
Lectithin used as emulsifier
Dipalmitoyl phosphatidyl choline formed as surfactant in lung cells

32. Phosphatidyl serine: a cephalin found in cell memranes

33. Sphinglipids: Sphingosine + fatty acid + something else

34. Ceramide: sphingosine + fatty acid

35. Sphingomyelin: sphingosine, fatty acid, phosphate and choline
Sphingomyelins found in myelin sheath around neurons

36. Sphingomyelin
Fatty acid
choline
phosphate

37. Glycolipid: Lipid + Carbohydrate Cerebroside: Sphingosine + fatty acid + carbohydrate

38. Lipid Storage Diseases

39. About 60% lipid and 40% protein
Biological Membranes
Separates cell interior from exterior, or cellular organelles from cytoplasml
About 60% lipid and 40% protein
Lipid mostly phosphoglyceride, sphingomyelin and cholesterol
Found as Lipid Bilayer

40. Lipid Bilayer

42. Blood Type Antigens Glc = glucose Gal = galactose GalNAc =
N-acetylgalactosamine
Fuc = fucose

43. Steroids Non-saponifiable lipids derived from cholesterol
Steroid Ring System

44. Cholesterol Found in Diet (animal fats)
Endogenous synthesized in liver

45. Cholesterol Essential component of cell membranes
Used as raw material for sex hormones and adrenocorticoid hormones
Used to make bile salts
High blood levels also associated with heart disease, atherosclerosis, arterial plaques

46. Cholesterol transported as Lipoprotein complex (LDL)

47. Lipoproteins classified by Density
HDL: High-density Lipoprotein
LDL: Low-density Lipoprotein
VLDV: Very low-density Lipoprotein
Triglycerides and cholesterol
Chylomicron
Mostly triglycerides

48. Biological flow of Cholesterol

49. Bile Salts: Glycocholate
Act as emulsifying agents to digest fats
Method for excreting cholesterol- bile is emulsion of cholesterol and bile salts
Gall stones form when cholesterol gets too concentrated

50. Adrenocorticoid hormones
Glucocorticoids:
regulate blood glucose levels
Cortisol and Cortisone
Also regulate inflammation, used to treat inflammatory diseases
Mineralcorticoids:
influences blood Na+ and Cl- levels
Aldosterone most important

51. cortisol
cortisone
aldosterone

52. Anabolic Steroids (fake testosterone)
Male Sex Hormones
Testosterone
Produced by testes
Male genitals and secondary sex characteristics
Muscle growth
Anabolic Steroids (fake testosterone)
Intended to prevent muscle atrophy
Used by athletes, widely banned
Bad side effects

53. Estrogen(estradiol, estrone) and progersterone
Female Sex Hormones
Estrogen(estradiol, estrone) and progersterone
Produced by ovaries
Reproductive cycle and secondary female characteristics
Mimicked by birth control pills

54. Prostaglandins Hormone like action
Regulates fever, contractions, inflammation
Induces labor, and asthma
Made from arachadonic acid
Synthesis inhibited by aspirin and cyclooxygenase inhibitors

55. Classification of Lipids