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1. Pages: 668Lipoprotein lipase acts in: A) hydrolysis of triacylglycerols of plasma lipoproteins to supply fatty acids to various tissues. B) intestinal uptake of dietary fat. C) intracellular lipid breakdown of lipoproteins. D) lipoprotein breakdown to supply needed amino acids. E) none of the above. 2. Pages: 669Free fatty acids in the bloodstream are: A) bound to hemoglobin. B) carried by the protein serum albumin. C) freely soluble in the aqueous phase of the blood. D) nonexistent; the blood does not contain free fatty acids. E) present at levels that are independent of epinephrine. 3. Pages: 669The role of hormone-sensitive triacylglycerol lipase is to: A) hydrolyze lipids stored in the liver. B) hydrolyze membrane phospholipids in hormone-producing cells. C) hydrolyze triacylglycerols stored in adipose tissue. D) synthesize lipids in adipose tissue. E) synthesize triacylglycerols in the liver. 4. Page: 674If the 16-carbon saturated fatty acid palmitate is oxidized completely to carbon dioxide and water (via the β-oxidation pathway and the citric acid cycle), and all of the energy-conserving products are used to drive ATP synthesis in the mitochondrion, the net yield of ATP per molecule of palmitate is: A) 3. B) 10. C) 25. D) 108. E) 1000.

Which of the following is not an intermediate of the citric acid cycle? A) Acetyl-coA B) Citrate C) Oxaloacetate D) Succinyl-coA E) α-Ketoglutarate Page: 644The reaction of the citric acid cycle that is most similar to the pyruvate dehydrogenase complexcatalyzed conversion of pyruvate to acetyl-CoA is the conversion of: A) citrate to isocitrate. B) fumarate to malate. C) malate to oxaloacetate. D) succinyl-CoA to succinate. E) α-ketoglutarate to succinyl-CoA. Page: 740– Which of the following is not a feature of complex IV? A) Cytochrome c is a one-electron donor. B) Oxygen is a substrate. C) Copper is an essential metal for the reaction. D) For every electron passed to complex IV, two protons are consumed from the matrix (N) side. E) In order to generate two water molecules, complex IV must go through the catalytic cycle two times. Page: 654Citrate synthase and the NAD+ -specific isocitrate dehydrogenase are two key regulatory enzymes of the citric acid cycle. These enzymes are inhibited by: A) acetyl-CoA and fructose 6-phosphate. B) AMP and/or NAD+ . C) AMP and/or NADH. D) ATP and/or NAD+

. E) ATP and/or NADH Page: 732Almost all of the oxygen (O2) one consumes in breathing is converted to: 1. Acetyl-CoA. 2. Carbon dioxide (CO2). 3. Carbon monoxide and then to carbon dioxide. 4. None of the above. 5. Water. Page: 739Cyanide, oligomycin, and 2,4-dinitrophenol (DNP) are inhibitors of mitochondrial aerobic phosphorylation. Which of the following statements correctly describes the mode of action of the three inhibitors? A) Cyanide and 2,4-dinitrophenol inhibit the respiratory chain, and oligomycin inhibits the synthesis of ATP. B) Cyanide inhibits the respiratory chain, whereas oligomycin and 2,4-dinitrophenol inhibit the synthesis of ATP. C) Cyanide, oligomycin, and 2,4-dinitrophenol compete with O2 for cytochrome oxidase (Complex IV). D) Oligomycin and cyanide inhibit synthesis of ATP; 2,4-dinitrophenol inhibits the respiratory chain. E) Oligomycin inhibits the respiratory chain, whereas cyanide and 2,4-dinitrophenol prevent the synthesis of ATP. Pages: 722-723 Which of the following statements about the chemiosmotic theory is correct? A) Electron transfer in mitochondria is accompanied by an asymmetric release of protons on one side of the inner mitochondrial membrane. B) It predicts that oxidative phosphorylation can occur even in the absence of an intact inner mitochondrial membrance. C) The effect of uncoupling reagents is a consequence of their ability to carry electrons through membranes. D) The membrane ATP synthase has no significant role in the chemiosmotic theory.

E) All of the above are correct. Page: 750Which of the following is correct concerning the mitochondrial ATP synthase? A) It can synthesize ATP after it is extracted from broken mitochondria. B) It catalyzes the formation of ATP even though the reaction has a large positive ∆G'°. C) It consists of F0 and F1 subunits, which are transmembrane (integral) polypeptides. D) It is actually an ATPase and only catalyzes the hydrolysis of ATP. E) When it catalyzes the ATP synthesis reaction, the ∆G'° is actually close to zero. Page: 763Mammals produce heat by using the endogenous uncoupling agent: A) the small molecule 2-4-Dinitrophenol synthesized by the cell. B) the protein thermogenin. C) the protein thioredoxin. D) the protein cytochrome c. E) a modified form of the FoF1 ATPase. Short Answer Questions 10. Page: 735 Consider a liver cell carrying out the oxidation of glucose under aerobic conditions. Suppose that we added a very potent and specific inhibitor of the mitochondrial ATP synthase, completely inhibiting this enzyme. Indicate whether each of the following statements about the effect of this inhibitor is true or false; if false, explain in a sentence or two why it is false. ____ (a) ATP production in the cell will quickly drop to zero. ____ (b) The rate of glucose consumption by this cell will decrease sharply. ____ (c) The rate of oxygen consumption will increase. ____ (d) The citric acid cycle will speed up to compensate. ____ (e) The cell will switch to fatty acid oxidation as an alternative to glucose oxidation, and the inhibitor will therefore have no effect on ATP production. a. False. Mitochondrial ATP synthesis will cease, but to compensate, cells will accelerate the production of ATP by glycolysis, preventing ATP levels from dropping to zero.

b. False. The acceleration of glycolysis noted above will actually increase the rate of glucose consumption. c. False. Because electron transfer through the respiratory chain is tightly coupled to ATP synthesis, blocking ATP synthase blocks electron flow and oxygen consumption. d. False. The citric acid cycle is an oxidative pathway, producing NADH. When electron flow from NADH to O2 is blocked, NADH accumulates, NAD+ is depleted, and the citric acid cycle slows for lack of an electron acceptor (NAD+). e. False. Oxidation of fats produces NADH, FADH2, and acetyl-CoA, which is further oxidized via the citric acid cycle. For the reasons noted above, blocking electron flow through the respiratory chain prevents ATP synthesis with energy from fatty acid oxidation

Which of the following statements about metabolism in the mammalian liver is false? A) Most plasma lipoproteins are synthesized in the liver. B) The enzymatic complement of liver tissue changes in response to changes in the diet. C) The liver synthesizes most of the urea produced in the body. D) The presence of glucose 6-phosphatase makes liver uniquely able to release glucose into the bloodstream. E) Under certain conditions, most of the functions of the liver can be performed by other organs. 2. Page: 949Which one of the following statements is true?

A) The brain prefers glucose as an energy source, but can use ketone bodies. B) Muscle cannot use fatty acids as an energy source. C) In a well-fed human, about equal amounts of energy are stored as glycogen and as triacylglycerol. D) Fatty acids cannot be used as an energy source in humans because humans lack the enzymes of the glyoxylate cycle. E) Amino acids are a preferable energy source over fatty acids. 3. Pages: 951An elevated insulin level in the blood:

A) inhibits glucose uptake by the liver. B) inhibits glycogen synthesis in the liver and muscle. C) results from a below-normal blood glucose level. D) stimulates glycogen breakdown in liver. E) stimulates synthesis of fatty acids and triacylglycerols in the liver. 4. Pages: 956The largest energy store in a well-nourished human is: A) ATP in all tissues. B) blood glucose. C) liver glycogen. D) muscle glycogen. E) triacylglycerols in adipose tissue. Epinephrine triggers an increased rate of glycolysis in muscle by: A) activation of hexokinase. B) activation of phosphofructokinase-1. C) conversion of glycogen phosphorylase a to glycogen phosphorylase b. D) inhibition of the Cori Cycle E) the Pasteur effect. Short Answer Questions 6. Page: 933Some hormones trigger very rapid responses, whereas for others the response takes much longer to develop. What generalization about the mechanisms of action of these two types of hormones can explain the differences in response times? Fast-acting hormones affect the activity of preexisting cellular enzymes. Slow-acting hormones alter gene expression thereby changing the levels of active cellular components. 7. Page: 940Describe five possible fates for glucose 6-phosphate in the liver. (1) conversion to liver glycogen; (2) dephosphorylation and release of glucose into bloodstream; (3) oxidation via the pentose phosphate pathway;

(4) oxidation via glycolysis and the citric acid cycle; (5) oxidation to acetyl-CoA, which then serves as precursor for synthesis of triacylglycerols, phospholipids, and cholesterol. 8. Pages: 941Describe five possible fates of amino acids arriving in the liver after intestinal uptake. (1) synthesis of nucleotides; (2) synthesis of hormones; (3) synthesis of other nitrogenous products such as porphyrins; (4) deamination, followed by oxidation of carbon skeleton for energy; (5) synthesis of proteins for export to plasma; (6) synthesis of proteins for liver; (7) export of free amino acids to other tissues 9. Pagse: 942Describe five possible fates for fatty acids in the liver. (1) conversion to triacylglycerol or cholesterol esters for export in plasma lipoproteins; (2) conversion into hepatocyte phospholipids; (3) oxidation and conversion to ketone bodies for export to other tissues; (4)  oxidation to acetyl-CoA, and further oxidation via citric acid cycle for ATP production; (5)  oxidation to acetyl-CoA, followed by synthesis of cholesterol from acetyl-CoA; (6) binding to serum albumin for transport to heart and skeleton. 10. Pages: 951Compare in general terms the effects of epinephrine, glucagon, and insulin on glucose metabolism. Epinephrine and glucagon cause an increase in the blood glucose level. Epinephrine acts when a higher than normal level of glucose is required; glucagon acts when the level is unusually low. Both stimulate gluconeogenesis and glycogen breakdown and decrease glycolysis and glycogen synthesis. Insulin causes a decrease in blood glucose levels; it acts by increasing glycogen synthesis, glycolysis, and glucose uptake by cells as well as by decreasing...