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CH 343 - CHAPTER 19 STUDY GUIDE
1. Be able to draw the structures of individual fatty acids given their short hand notation (16:0,18:1 “del”9, for example), including omega-three fatty acids, and also for triglycerides given thefatty acyl composition.
2. Know the initial phases of digestion/metabolism of fats from intestine to storage in adipocytes(roles of bile salts or acids, intestinal or pancreatic lipase, chylomicrons, chylomicron remnants,VLDL, lipoprotein lipase). Also functions of LDL and HDL and their roles in cholesteroltransport. You should also know the very short heart disease connection between oxidized LDL,atherosclerotic plaque, the scavenger receptor on macrophages, etc. as we went over this in class(if only to get you to stop or never smoke). This receptor is not subject to down regulation,unlike the normal LDL receptor (Fig 19-8)3. Mobilization of stored triglycerides in adipocytes via hormone-sensitive lipase, and thehormonal connection to carbohydrate metabolism. How are fatty acids transported to musclecells? Recall that muscle cells store glycogen in small amounts; during exertion the preferredfuel of muscle cells is carbohydrate. However, during times of rest, the preferred fuels are fattyacids from adipocytes (and to some extent, ketone bodies from the liver). 4. How are fatty acids activated (or “primed”) prior to their catabolism via beta-oxidation, andwhat cellular compartments do these processes occur in? What is the role of carnitine?5. What is the similarity between the reactions of beta-oxidation and reactions in the citric acidcycle? Be able to draw these structural similarities. 6. Be able to determine the ATP yield from a saturated acid such as 16:0 and also for theirstorage forms, triglycerides. Keep in mind that this requires that you know the ATP count forglycerol, which is a product of fat hydrolysis.
7. Know only that unsaturated fatty acids require two auxiliary enzymes (isomerase andreductase in Figure 19-15) in addition to the enzymes of beta-oxidation. Know why theseauxiliary enzymes are required but not structural details. You should also know how thepresence of both single and multiple double bonds affects the ATP yield.
8. In what way does catabolism of odd-chain fatty acids differ from catabolism of even-chainfatty acids (Figure 19-16)? Specifically, how is the final three-carbon product of beta oxidationcatabolized? What two additional coenzyme requirements are there, and why are theynecessary? Be able to determine ATP yield. Why isn’t the succinyl CoA, a citric acid cycleintermediate which is produced during odd-chain fatty acid catabolism, consumed by the citricacid cycle? How, then, is it catabolized (see p. 648)? What is the importance of malic enzymein this regard, and also, later on, in the catabolism of glucogenic amino acids? Note that this willaffect the ATP count.
9. What are ketone bodies, why and how are they formed, know their structures, what they’reused for. Which of the ketone bodies is exportable by the liver as a form of fuel, and how is itcatabolized?10. As far as section 4 material is concerned, you’re responsible for very little of this material(only that covered in in class). For example, where biosynthesis occurs as opposed tobreakdown, the role of malonyl CoA in both activating, as it were, acetyl CoA and also its role inregulation (see #11). The material not covered in class but in my notes will not be on the exam11. Regulation of fatty acid metabolism as we discussed it in class - refer to Figure 19-32.
12. Skip all of sections 6. 13. Know cholesterol biosynthesis as far as HMG-CoA (reactions similar to those of ketone body formation) How do statins such as Crestor work?14. Problems: 1, 2, 3, 5, 6, 7

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