1 / 29

LIPIDS

LIPIDS . Digestion .. Absorption .. Transportation .. Metabolism. Dina Trabzuni. Lipids consist of two parts Glycerol Fatty Acids a. Saturated fatty acids b. Unsaturated fatty acids . Monounsaturated . Polyunsaturated. Figure 3 : Formation of TG. Table 1 : Saturated fatty acids .

medwin
Download Presentation

LIPIDS

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. LIPIDS Digestion .. Absorption .. Transportation .. Metabolism Dina Trabzuni

  2. Lipids consist of two parts • Glycerol • Fatty Acids • a. Saturated fatty acids • b. Unsaturated fatty acids.Monounsaturated .Polyunsaturated Figure 3 : Formation of TG

  3. Table 1 :Saturated fatty acids

  4. Table 2 :Unsaturated fatty acids

  5. Lipids are classified as simple or complex • Simple lipid • a.Fatty acids • b. neutral fats (monoglyceride, • diglycerde, and triglyceride) • c. waxes • Complex lipids • a. Phospholipids • b. Glycolipids • c. Lipoproteins • 3. Derived lipids Figure 1 : Triglyceride Figure 2 : Phosphatidic acid

  6. Omega Fatty acid

  7. Cis- Trans Fatty acid

  8. Function of Fat . Energy . Essential nutrient . Flavor and Satisfaction . Adipose Tissue .Cell membrane Structure Fat in Food Fat in Body

  9. Food Sources of Fat . Meat Fat (bacon, sausage….) . Dairy Fats and products (cream, butter, cheese..) . Egg yolk . Monounsaturated , polyunsaturated Fatty acid .Vegetable oil (safflower, corn, soybean, cottonseed, olive oil) Animal Fats Plant Fat

  10. Characteristics Of Food Fat Sources . Butter, margarin, salad oils and dressing,shirteninig fat meat . Chees, cream portion of homogenised milk, egg yolk, nuts, seeds, olives….. Visible Fat Invisible Fat

  11. Digestion of lipids • In mouth • mechanical digestion Lingual Lipase • In stomach • mechanical digestion • Gastric lipase

  12. In small intestine • Bile acid, Pancreatic Lipase, Cholesterol esterase, Phospholipase Pancreatic lipase Triglycerides Triglycerides 2 fatty acids + Mono glycerides 1 fatty acids + Diglycerides Pancreatic lipase Triglycerides 3 fatty acids + glycerol

  13. Absorption of lipids Figure 4 : Absorption of fat.

  14. Transportation of lipids Table 3Lipids are transported in the plasma as lipoproteins.

  15. Lipids Metabolism . Liver and Adipose tissue play a central role in lipid metabolism. . Adipose tissue is the main store of triglyceride in the body. . Lipid metabolism either lipolysis or lipogenesis. . Fatty acids are both oxidized to acetyl CoA and synthesized from acetyl CoA.

  16. Lipolysis . Complete hydorlysis of triglyceride yeild gelycerol and 3 fatty acids. . Fatty acids oxidiation take place in the mitochonderia. . Fatty acids are activated before being catabolized (oxidized). Fatty acid + ATP + CoA Acyl CoA + AMP + PPi acyl CoA synthetase

  17. Long chain fatty acids penetrate the inner -Mitochinderial membrane as carnitine derivatives. Figure 5 : Role of carnitine in the transport of long chain fatty acids.

  18. β - oxidation pathway of fatty acids . Many tissues are capable of oxidizing fatty acids in the mitochondria by β - oxidation pathway. . The chain is broken between the α (2) and β (3) carbon atoms. Figure 6 : Overview of β - oxidation pathway of fatty acids

  19. β - oxidation of fatty acids (Figure 7)

  20. The products of oxidation of fatty acids Oxidation of fatty acids produces a large quantity of ATP, .example : Palmitic acid (C:16 ) 7 cycles from 7 NADH + 7 FADH2 (7 x5 = 35 ATP) 7 cycles from 8 Acetyl CoA (8 x 12 = 96 ATP) 2 ATP for the initial activation of fatty acid ( 35 +96 – 2 = 129 molecule of ATP) Figure 8 : acetyl CoA product

  21. Oxidation of unsaturated fatty acids occurs by amodified β - oxidation pathway (figure9)

  22. Ketone bodies Ketogenesis occurs when there is a high rate of fatty acid oxidation in the Liver (figure 10). Acetyl CoA Acetyl CoA CoA Aceto acetyl CoA CoA Acetoacetate β -hydroxy butyrate Acetone

  23. Lipogenesis . The body is capable of synthesizing fatty acids in the cytoplast of the cell from starter ( acetyl CoA + malonyl CoA). . Malonyl CoA is formed from Acetyl CoA Figure 11 : Biosynthesis of Malonyl CoA

  24. . Acetyl CoA transfer to the cytoplast across the mitochondrial membrane in the form of citrate Figure 12 : Conversion the citrate to Oxaloacetate and Acetyl CoA. . The enzymes involved in fatty acid synthesis are arranged in a complex called the fatty acid synthase system.

  25. The steps in the synthesis of fatty acid ( Figure 13)

  26. Cholesterol . Cholesterol is not an energy producing nutrient. • . It is an essential structural • component of membrane of the outer layer of plasma lipoprotien. • Bile acids and steriod hormones are formed from cholesterol. • . Cholesteryl ester is a storage form of cholesterol which is found in most tissues. Figure 14 : Cholesterol

  27. Acetyl CoA CoA Acetyl CoA CoA Inhibition HMG-CoA reductase Cyclization Acetyl CoA is the source of all carbon atoms in cholesterol Acetoacetyl CoA β -hydroxy- β- methylglutaryl CoA Mevalonate Squalene Farmesyl pyrophosphate

  28. References Brene, R., Levy, M., Koeppen, B., Stanton, B., (2004) Physiology, Fifth edition. Mosby. Fox, S., (2004) Human Physiology, Eighth edition. Mc Graw Hill. Hunt, S., Groff, J., (1997) Advanced Nutrition and Human Metabolism, West Puplishing Company. Lehninger, A., Nelson, D., Cox, M.,(1993) Principles of Biochemistry, 2nd edtion. Worth Puplishers. Murray, R., Granner, D., Mayes, P., Rodwell, V., (1996) Haper’s Biochemistry, 24th edition, Prentic-Hall International, Inc. Seeley, R., Stephens, T., Tate, P., (1992) Anatomy and Physiology,Mosby Yearbook.

  29. Thank you

More Related