1. LEHNINGER PRINCIPLES OF BIOCHEMISTRY Sixth Edition David L. Nelson and Michael M. Cox © 2013 W. H. Freeman and Company CHAPTER 17 Fatty Acid Catabolism

2. Triacylglycerols (fats or triglycerides) Three fatty acids ester-linked to a glycerol molecule Used as energy storage molecules in eukaryotes Stored in adipocytes

3. Advantages of using triacylglycerols for energy storage Disadvantages of triacylglycerols as energy storage 1. Fats are highly reduced hydrocarbons with a large energy of oxidation. 2. Fats are insoluble molecules that aggregate into droplets. They are unsolvated and no storage mass is water. 3. Fats are chemically inert. They can be stored without fear of unfavorable reactions. 1. Fats must be emulsified before enzymes can digest them. 2. Fats are insoluble in the blood and must be carried in the blood as protein complexes.

4. Extraction of energy from fatty acids Step 1. Oxidation of fatty acids to acetyl-CoA. This generates NADH and FADH 2. Step 2. Oxidation of acetyl-CoA to CO 2 in the citric acid cycle. This generates NADH, FADH 2 and GTP (ATP). Step 3. Transfer of electrons from NADH and FADH 2 to O 2. This results in the synthesis of ATP.

6. Lipoproteins Lipoproteins are large complexes of lipids and proteins designed to transport lipids in the blood. The lipoproteins are classified by particle density. 1. Chylomicrons (transport dietary cholesterol to tissues) 2. Very low density lipoprotein (VLDL)transport cholesterol 3. Intermediate density lipoprotein (IDL)produced by the liver to 4. Low density lipoprotein (LDL)tissues 5. High density lipoprotein (HDL) (transport cholesterol from tissues to liver)

8. Molecular Structure of a Chylomicron

9. Utilization of stored triacylglycerols

10. Metabolic fate of the glycerol backbone of triacylglycerols

11. Fatty acyl-CoA synthetases

12. Fatty acid entry into mitochondria

16. Beta oxidation of oleate 18:1Δ 9

17. Beta oxidation of linoleate 18:2Δ 9,12

18. b-oxidation of fatty acids with an odd number of carbons produces propionyl-CoA. Propionyl-CoA is converted to succinyl-CoA for entry into the citric acid cycle.

19. Ketone bodies can be formed from acetyl-CoA resulting from  -oxidation of fatty acids. Ketone bodies are exported from the liver to other tissues to be used as fuel.

20. Starvation increases synthesis of ketone bodies