1. Midterm is 7 November in class Lectures 1-6 inclusive-50 multiple choice-50 points One short answer question-10 points Lecture 5- 10 October 2013 Most of this lecture taken from Chapters 5,7 of Rolfes et al(Understanding Normal and Clinical Nutrition(Nutrition 2104/2106 text)

2. Outline of lecture 5 Lipids classified -fatty acids -saturation -triglycerides -phospholipids -sterols

3. Outline of lecture 5 Lipids -digestion -absorption -transport

4. Outline of lecture 5 Lipids in the body -roles of triglycerides -essential fatty acids

5. Outline of lecture 5 Preview of lipid metabolism

6. Outline of lecture 5 Lipid Metabolism -fatty acid catabolism -fatty acid anabolism -triglyceride catabolism -triglyceride anabolism -cholesterol catabolism -cholesterol anabolism -phospholipid catabolism -phospholipid anabolism -regulation

7. More detailed comments

8. Lipids defined a diverse group of compounds found in all living cells, insoluble in water but soluble in organic solvents such as ether, acetone and chloroform, and which include fats, oils, triacylglycerols, fatty acids, glycolipids, phospholipids and steroids, some lipids being essential components of biological membranes, others acting as energy stores and fuel molecules for cells.

9. Lipids classified -fatty acids -straight hydrocarbon chain terminating with a carboxylic acid group

10. Lipids classified -fatty acids -saturation -saturated-no double bonds between carbons in a fatty acid chain

11. Lipids classified -fatty acids -diagram and partial list of saturated fatty acids -myristic acid 14:0 -palmitic acid 16:0 -stearic acid 18:0

13. Lipids classified -fatty acids monounsaturated-one double bond between carbons in a fatty acid chain -diagram and partial list of mono-unsaturated fatty acids -palmitoleic acid 16:1n-7 -oleic acid 18:1n-9

15. Lipids classified -fatty acids -polyunsaturated- more than one double bond between carbons in a fatty acid chain

16. - diagram and partial list of polyunsaturated fatty acids

18. -diagram of omega 3 vs omega 6 fatty acids

20. Lipids classified Polyunsaturated – a partial list Omega 6 -linoleic acid 18:2 -gamma-linolenic acid 18:3 -dihomogammalinolenic acid 20:3 -arachidonic acid 20:4 Omega 3 -alpha-linolenic acid 18:3 -eicosapentaenoic acid 20:5 -docosahexaenoic acid 22:6

22. Lipids classified -cis and trans configurations -diagram

24. Lipids classified -triglycerides -three fatty acids attached to a glycerol backbone -diagram

25. Lipids classified

26. Lipids classified -phospholipids example-choline containing phospholipids 2 fatty acids and a choline head group attached to glycerol -diagram

28. Lipids classified -phospholipids -ethanolamine containing phospholipids -2 fatty acids and an ethanolamine head group attached to glycerol -phosphatidylinositol -2 fatty acids and an inositol head group attached to glycerol

29. Lipids classified -phospholipids -phosphatidylserine -2 fatty acids and a serine head group attached to glycerol -sphingomyelin -one fatty acid and 2 other groups attached to glycerol

30. Lipids classified -sterols -cholesterol -various hormones (eg estrogen, testosterone) made from cholesterol

31. Diag chol

32. Lipids -digestion -mouth -lingual lipase -adults-minor role -infants- major role in digesting short and medium chain fatty acids

33. Lipids -digestion -stomach-no digestion -small intestine- pancreatic lipase-digests fatty acids from triglycerides -role of bile (figure 5-14, Rolfes)

35. Lipids -absorption -glycerol, short and medium chain fatty acids go directly into blood -monoglycerides and long chain fatty acids are formed into micelles which are moved into intestinal cells in intestinal cells ultimately get phospholipids and triglycerides formed into chylomicrons which are moved into lymph - from lymph go into blood

36. Lipids -transport lipoproteins -fat protein particles-protein required to give water solubility to lipids -chylomicrons -very low density lipoprotein -low density lipoprotein -lipoprotein (a) -high density lipoprotein -albumin -lipoprotein density affected by ratio of lipid to protein in a lipoprotein

37. Lipids in the body -roles of triglycerides -primarily energy -fat stores -participates in carbohydrate metabolism -protein sparing

38. Lipids in the body -essential fatty acids -linoleic -alpha-linolenic

39. Preview of lipid metabolism -fat is made into fat -carbohydrate and protein can make fat

40. Lipid Metabolism -fatty acid catabolism -fatty acids made into acetyl CoA -acetyl CoA follows TCA cycle -ATP is made

41. Lipid Metabolism -fatty acid anabolism -acetyl CoA can be made into fatty acids -omega 6 and omega 3 pathways -ATP is used

42. Lipid Metabolism -triglyceride catabolism -to glycerol and fatty acids -triglyceride anabolism -fatty acids and glycerol make triglycerides

43. Lipid Metabolism -cholesterol catabolism -largely made into bile -cholesterol anabolism -acetyl CoA made into cholesterol

44. Lipid Metabolism -phospholipid catabolism -made into glycerol, fatty acids and head group (eg choline) -phospholipid anabolism -made from glycerol, fatty acids and head group (eg choline)

45. Lipid Metabolism -regulation-closely linked to carbohydrate availability -lots of carbohydrate-favours fatty acid synthesis-due to lots of malonyl CoA which inhibits carnitine acyl transferase I that allows for transfer of fatty acids to carnitine for transport into mitochondria for oxidation to acetyl CoA- also if not enough carbohydrate for fatty acid synthesis but not so little that there is sufficient OAA-fatty acids are metabolised through the Krebs cycle (acetyl CoA from fatty acids joins with OAA to make citrate) -little carbohydrate-favours fatty acid catabolism to ketones (acetyl CoA is converted to ketone as OAA is converted to glucose)