Ch 20 Fatty Acid Metabolism

36. An important structural lipid found in nerve cell membranes, ______, is a type of ______.

sphingomyelin, phospholipid

5. LDL taken up by the liver is

taken up by the ER and used to control synthesis of HMG CoA reductase and LDL receptor synthesis.

6. Which of the following is NOT an example of a problem sometimes associated with unsaturated fatty acid breakdown?

α, β double bond.

7. Cells take up ____ by receptor mediated endocytosis.

LDL

45. Which of the following vitamins is part of the prosthetic group 5-deoxyadenosylcobalamin?

B12

25. What is the net production of ATP from complete catabolism of the following fatty acid to CO2 and H2O? 10 carbons

51-90

11. Which of the following enzymes is NOT involved in the tricarboxylate transport system? Option A: acetyl CoA and acetyl-CoA Option B: HMG-CoA and acyl-CoA Option C: acetone and betahydroxybutyrate Option D: malonyl-CoA and acyl-CoA Option E: DHAP and glycerol-3-phosphate

All are involved in the transport of acetyl-CoA into the cytosol

20. Which statement concerning phospholipid synthesis is true? A Option A: Addition of polar "head groups" to diacylglycerol usually involves CDP derivatives. B Option B: Addition of polar "head groups" to diacylglycerol usually involves UDP adducts. C Option C: Addition of fatty acyl "tails" to glycerol usually involves CDP adducts. D Option D: Addition of fatty acyl "tails" to glycerol usually involves UDP adducts. E Option E: None of the above is true.

Answer A: Addition of polar "head groups" to diacylglycerol usually involves CDP derivatives.

48. ________ is formed from ordered sequence of condensation of isoprene units.

Cholesterol

29. The glycerol backbone of triacylglycerols is catabolized to ________ .

Dihydroxyacetone phosphate

43. Triacylglycerols are synthesized by ____ during times of starvation via a process known as ____.

Dihydroxyacetone phosphate; glyceroneogenesis

14. Considering the figure below, what compound would be formed by action of acyl-CoA dehydrogenase? (Fatty Acyl-CoA)

Fatty Acyl SCoA with a double bond between a/b bonds

39. Cholesterol and other lipids are transported from tissues to the liver by ________.

HDL

40. Which of the following accurately ranks lipoproteins from highest to lowest density?

HDL > LDL > IDL > VLDL > chylomicrons

19. An enzyme that is inhibited by the statin group of drugs (e.g. Lipitor®) is

HMG CoA reductase.

28. Which enzyme catalyses the key regulatory step of cholesterol synthesis?

HMG-CoA reductase

15. Which of the following is FALSE regarding HMG-CoA reductase? A Option A: HMG-CoA reductase is highly regulated. B Option B: The active site is tightly bound by statins. C Option C: HMG-CoA reductase levels are increased as a result of high cholesterol concentrations in the endoplasmic reticulum. D Option D: HMG-CoA reductase levels are decreased as a result of high cholesterol concentrations in the endoplasmic reticulum. E Option E: HMG-CoA reductase is levels are decreased by the same factor that down regulated production of the LDL receptors.

HMG-CoA reductase levels are increased as a result of high cholesterol concentrations in the endoplasmic reticulum.

24. Which of the following could be produced by the reaction of two or more of phosphatidic acids with two or more glycerol-3-phosphates? I. phosphatidylglycerol II. cardiolipin III. phosphatidylinositol IV. gangliosides

I, II

46. Which of the following is required for entry of fatty acids into the oxidation pathway? I. priming via the enzyme acyl CoA synthetase II. conservation of free energy from ATP hydrolysis by use of a thioester linkage III. transport to the cytosol for oxidation via a carnitine carrier protein IV. hydrolysis of carnitine palmitoyl transfer protein

I, II

27. Sphinganine is an intermediate in the synthesis of which of the following? I. ceramides II. spingomyelins III. cerebrosides IV. prostaglandins

I, II, III

22. Which statement concerning fatty acid synthesis is TRUE? I. The process occurs in the cytosol. II. In eukaryotes, the process occurs on a single large protein. III. The growing acyl chain is carried on an acyl carrier protein instead of coenzyme A. IV. The process requires two NADPH per acetyl group (2 carbons) added.

I, II, III, IV

38. Which of the following statements about apolipoproteins (with the possible exception of apoB-100) is TRUE? I. The apolipoproteins are water-soluble and loosely associate with the lipoproteins. II. The apolipoproteins contain helices with hydrophobic and hydrophilic groups on opposite sides of the helical cylinder. III. The apolipoproteins are synthesized in the intestinal tissues. IV. The apolipoproteins appear to float on the surface of phospholipids.

I, II, IV

26. Which of the following is TRUE regarding the enzyme acetyl-CoA carboxylase? I. It catalyzes the first committed step in fatty acid oxidation. II. It requires S-adenosylmethionine. III. It produces malonyl CoA. IV. It uses acetyl CoA.

III, IV

34. Cholesterol is a precursor to I. prostaglandins II. vitamin K III. steroid hormones such as androgens IV. bile acids

III, IV

32. Which of the following compounds are required to make sphingosine? I. palmitoyl-CoA II. serine III. acetyl-CoA IV. isoprene V. arachidonic acid

Option D: I, II

37. Which of the following statements about peroxisomes is FALSE? Option A: β oxidation in peroxisomes can shorten very long fatty acids. Option B: Mammalian peroxisomes can synthesize some lipids, including bile salts. Option C: In plants, peroxisomes and glyoxysomes serve as the site of β oxidation. Option D: Long chain fatty acids are transported into the peroxisome via a carnitine carrier protein where they are activated for oxidation. Option E: β oxidation in peroxisomes varies slightly from the mitochondrial process.

Option D: Long chain fatty acids are transported into the peroxisome via a carnitine carrier protein where they are activated for oxidation.

33. Which of the following best describes arachidonic acid?

a 20-carbon fatty acid used for synthesis of prostaglandins

16. Which of the following is the starting metabolite in ketone body biosynthesis?

acetyl CoA

10. Which of the following components would be condensed to form acetoacetate?

acetyl CoA and acetyl-CoA

49. Digestion of triacylglycerols is aided by the cholesterol derivatives synthesized by the liver known as

acids

18. Free fatty acids bind to ________ for circulation in the bloodstream.

albumin

12. PGH2 is synthesized from ______ and triggers pain and ________.

arachidonate; inflammation

13. Which of the following drugs acts by acetylating a serine residue preventing adequate enzyme activity?

aspirin

42. Two phosphatidylglycerol molecules condense to form the molecule ______, and glycerol is eliminated as the side product.

cardiolipin

50. Lipoproteins formed in the intestinal mucosal cells are called ________.

chylomicrons

23. The mechanism of the condensing enzyme (KS) of fatty acid synthase is best described as

covalent catalysis using a cys residue in the active site

30. In which cellular compartment does the following reaction take place? HMG-CoA + 2 NADPH → mevalonate + 2 NADP+ + Acetyl-CoA

cytosol of liver cells

9. Which of the following is the correct sequence of events in cholesterol synthesis? (Note: not all events in the sequence are included)

dimethylallyl pyrophosphate > geranyl pyrophosphate > farnesyl pyrophosphate > squalene

21. Which of the following diets would most likely promote the formation of ketone bodies?

high fat, high protein, low carbohydrate

47. Which of the following would result in a net increase in uptake of LDL by the liver?

high levels of cholesterol synthesis

41. The activity of lipases is controlled in part by a process known as ____ which functions effectively due to the ____ where lipases are active.

interfacial activation; lipid-water interface

3. The molecules acetoacetate, acetone, and D-β-hydroxybutyrate are metabolic fuels termed ________.

ketone bodies

44. ______, a condition in which acetoacetate production exceeds it metabolism and results in a sweet breath odor due to nonenzymatic ___ of acetoacetate to _____.

ketosis; decarboxylation; acetone

8. Which of the following compounds is produced by the multistep cyclization of squalene?

lanosterol

17. Which of the following is the source of the two carbon fragments in fatty acids biosynthesis?

malonyl CoA

1. Fatty acid synthesis requires both acetyl-CoA and ________ as initiator molecules.

malonyl-CoA

31. In which location listed below does the following reaction take place? HMG-CoA → acetoacetate + Acetyl-CoA

mitochondria of liver cells

2. Acyl carrier protein (ACP) contains a ________ prosthetic group.

phosphopantetheine

4. The β oxidation of odd-numbered fatty acids results in ________ as a final product.

propionyl-CoA

35. Pain and inflammation are triggered by ___ which are synthesized by an enzyme inhibited by ____.

prostaglandins; aspirin