※<19> 1. Choose the correct path taken by a pair of electrons as it travels down the electron transport chain: A?????????? NADH?→?complex I?→?complex II?→?Co Q?→?complex III?→?Cyt C?→?complex IV?→?O2 B?????????? FADH2 →complex I →Co Q?→?complex III?→?Cyt C?→?complex IV?→?O2 C?????????? NADH →complex II →Cyt C?→?complex III?→?Co Q?→?complex IV?→?O2 D????????? NADH →complex I?→?Co Q?→?complex III?→?Cyt C?→?complex IV?→?O2  2. In the binding-change mechanism for ATP synthase, A????????? every proton that is translocated causes the formation of 1 ATP B????????? ADP and Pi bind to the ?-??protomer in the L conformation. C????????? ATP binds to the ?-??protomer in the O conformation D????????? All three ?-??protomers cycle through the same conformation at the same time  3. Which of the electron transport complexes are responsible for translocating protons into the intermembrane space? A????????? Complex I, II, III, and IV. B????????? Complex I, III, and IV. C????????? Complex II and cytochrome c D????????? Complex I, III, IV and V E????????? Complex I and IV.  4. Which of the following is not correct concerning the uncoupling of electron transport from oxidative phosphorylation: A????????? uncoupling slows all aerobic metabolic activities. B????????? uncoupling slows the citric acid cycle C????????? stops electron transport D????????? stops ATP synthesis.  5. Which of the following is not a redox center in the electron transport chain? A????????? FMN B????????? Fe-S clusters C????????? Co Q D????????? cytochromes E????????? hemoglobin  6. The pH in the mitochondrial matrix is ___ than the pH in the intermembrane space. 1)?????? lower 2) higher  7. The mitochondrial matrix A??????????? Is a dilute solution of protein (about 50% protein) B??????????? Is basic relative to the cytoplasm of the cell C??????????? Is the location of the enzymes of fatty acid biosynthesis D?????????? Is separated from the cytoplasm by two membranes  8. The electron transport chain A??????? Has components with mostly more positive electrode potentials going from NADH to O2 B?????? Has both 2 and 1 electron carriers C?????? Is a strictly linear, unbranched pathway (remember succinate dehydrogenase)  9. The bc1 complex (complex III) A?????????? Has a flavin B?????????? Sends the two electrons from reduced quinone on separate pathways C?????????? Oxidizes quinol on one side of the membrane and reduces it on the other D?????????? Is an important part of all bacterial electron transport chains  10. Coupling between electron transport and ATP synthesis A?????? Provides the control by which oxidation rates are governed by ATP utilization B?????? Is eliminated by uncouplers which inhibit the ATP synthase (Is eliminated, but uncouplers don’t inhibit ATP synthase) C?????? Is always tight in animal mitochondria under physiological conditions (remember brown fat and thermogenesis) D?????? Is eliminated by lipid-soluble weak acids  11. Mitochondrial electron transport A?????? Is accomplished by both electron and hydride movements B?????? Proceeds in the absence of ATP synthesis C?????? Is accompanied by movements of protons across the membrane D?????? Can start with a variety of substrates, such as lactate, formate, glycerol-3P, succinate and NADH  12.Uncoupling of mitochondrial oxidative phosphorylation: A?????? halts all mitochondrial metabolism. B?????? slows down the citric acid cycle. C?????? allows continued mitochondrial ATP formation, but halts O2 consumption. D?????? halts mitochondrial ATP formation, but allows continued O2 consumption. E??????? none of the above.  13. Which of the following statements about the chemiosmotic theory is correct? A?????? Electron transfer in mitochondria is accompanied by a release of protons on one side of the inner mitochondrial membrane. B?????? The effect of uncoupling reagents is a consequence of their ability to carry electrons through membranes. C?????? Although energy transductions in mitochondria and in chloroplasts are superficially similar, they have fundamentally different mechanisms. D?????? The membrane ATPsynthase, which plays an important role in other hypotheses for energy coupling, has no significant role in the chemiosmotic theory. E??????? All of the above statements are correct.  14. The rate of flow of electrons through the electron-transport chain is regulated by A?????? the ATP:ADP ratio. B?????? the concentration of acetyl CoA. C?????? the rate of oxidative phosphorylation. D?????? feedback inhibition by H2O. E??????? the catalytic rate of cytochrome oxidase.  15. Which of the following experimental observations would not support the chemiosmotic model of oxidative phosphorylation? A?????? If mitochondrial membranes are ruptured, oxidative phosphorylation cannot occur. B?????? Raising the pH of the fluid in the intermembrane space results in ATP synthesis in the matrix. C?????? Transfer of electrons through the respiratory chain results in formation of a proton gradient across the inner mitochondrial membrane. D?????? The orientation of the enzyme complexes of the electron transfer chain results in a unidirectional flow of H+. E??????? Radioactively labeled inorganic phosphate is incorporated into cytosolic ATP only in the presence of an H+ gradient across the inner mitochondrial membrane.  16.Indicate whether each of the following statements about the mitochondrial electron transfer chain and oxidative phosphorylation is true (T) or false (F). A?????? NADH dehydrogenase complex, cytochrome bc1 complex, and cytochrome oxidase all are transmembrane proteins. B?????? Synthesized ATP must be transported into the intermembrane space before it can enter the cytosol. C?????? Cytochrome c and the F1 part of ATPase are peripheral membrane protein. D?????? Complexes I, II, III, and IV all are proton pumps. E??????? Ubiquinone is a hydrophilic molecule. F??????? Ubiquinone and the Fo part of ATP synthase are both peripheral membrane proteins. G?????? The final electron acceptor is H2O.  17. In order to examine the citric acid cycle you have obtained a pure preparation of isolated, intact mitochondria. You add some succinyl-CoA to the suspension of mitochondria. How many moles of ATP would you expect to be generated in one turn of the citric acid cycle from each mole of succinyl-CoA added to the test tube? 1) 3 2) 4 3) 5 4) 5.5 5) No ATP would form under these conditions.  5 ※<20> ? 1. A patient has sporadic bouts of fainting that are found to correlate with hypoglycemic episodes. The hypoglycemia is easily cured by ingestion of food. There is a history of this ailment in the patient's family. The most likely explanation is a defect in A????????? GLUT4 transporter B????????? insulin receptor C????????? liver glycogen synthase D???????? muscle glycogen phosphorylase(e) muscle 6-phosphofructo-1-kinase  2. Glucose uptake by skeletal muscle is increased by exercise because of an increase in the intracellular concentration of A????????? AMP B????????? ADP C????????? ATP D???????? creatine phosphate E????????? NADH  3. Relative to the well-fed state, which of the following is increased in the liver in the starved state? A????????? AMP concentration B????????? Fructose-2,6-bisphosphatase activity C????????? Pyruvate dehydrogenase activity D???????? Pyruvate kinase activity  4. The synthesis of glycogen, starch and lactose A.????? uses glucose-1-phosphate as the only substrate. B.????? uses a sugar nucleotide as a substrate. C.????? only takes place in the liver of mammals. D.????? involves the addition of a sugar residue at the reducing end of the a growing polymer.  5. An enzyme used in both glycolysis and gluconeogensis is: A. hexokinase B. glucose-6-phosphatase C. phosphoglycerate kinase D. pyruvate carboxylase E.????? phosphofructokinase  6. One cycle of the citric acid cycle produces ______ moles of NADH, _____ moles of FADH2 and _____ moles of GTP : A. 3; 2; 0 B. 4; 2; 1 C. 3; 1; 1 D. 2; 2; 2  7. Which list of intermediates is in the correct order for the part of citric acid cycle that includes these intermediates? A. succinyl-CoA, succinate, ?-ketoglutarate, fumarate, malate B. ?-ketoglutarate, succinyl-CoA, succinate, fumarate, malate C. succinate, succinyl-CoA, fumarate, ?-ketoglutarate, malate D. ?-ketoglutarate, succinyl-CoA, succinate, malate, fumarate E. ?-ketoglutarate, malate, fumarate, succinyl-CoA, succinate  8. In glycolysis, substrate level phosphorylation is catalyzed by: A. hexokinase B. glyceraldehyde 3-phosphate dehydrogenase C. phosphofructokinase D. phosphoglycerate kinase  9. The first step of gluconeogensis is catalyzed by: A. hexokinase B. pyruvate carboxylase C. PEP carboxykinase D. pyruvate kinase  10.The reaction catalyzed by the pyruvate dehydrogenase complex can be divided all of the following stages except: A. Decarboxylation B. Oxidation C. Activation D. regeneration of cofactors E. all are stages in the reaction  11. Which of the following statements is correct about lactate A. it is the dead end product of anaerobic respiration in the muscle and liver B. it is transported from the muscle to the liver where it enters glycolysis C. it is transported from the liver to the muscle where it enters the citric acid cycle D. it is transported from the muscle to the liver where it is converted to glucose via gluconeogenesis  12. Animals can’t catalyze the net conversion of acetyl CoA into carbohydrates because A. synthesis pathways occur in the cytosol while the degradation pathways that occur in the mitochondria B. there is a net lose of two molecules of CO2 in the citric acid cycle C. acetyl CoA can not be converted to oxaloacetate D. there are no metabolic pathways that connect pathways that form acetyl CoA with those that form carbohydrates.  13. Germinating plant seeds can covert acetyl CoA into carbohydrates, whereas animals are incapable of converting fatty acids into glucose. This difference is because: A. animals have glycogen and don’t need to make glucose from fatty acids. B. plants use the glyoxylate cycle to convert two moles of acetyl Co A into L-malate which is converted into a precursor for gluconeogenesis. Animals do not have the glyoxylate cycle. C. plants can carry out photosynthesis which make the conversion of acetyl Co A into gluconeogensis precursors possible D. Both plants and animals have the glyoxylate cycle, but animals do not have a mechanism to convert L-malate into the precursors for gluconeogensis  14. Which of the following enzymes found in the citric acid cycle is a membrane bound protein? A. Aconitase B. Succinate dehydrogenase C. Succinyl CoA Synthetase D. Malate dehydrogenase  15. Which of the following is not correct concerning the isomerization of citrate to isocitrate: A. the enzyme contains a unique Fe-S cluster. B. converts a tertiary alcohol ( which can not be oxidized) to a secondary alcohol that can be oxidized C. it is a major control step in the citric acid cycle D. all are correct  16. The two main purposes of the citric acid cycle are: A. synthesis of citrate and gluconeogenesis B. degradation of acetyl Co A to produce energy and supply of precursors for biomolecules C. degradation of pyruvate to produce energy and supply of precursors for biomolecules D. degradation of acetyl Co A to produce energy and gluconeogenesis  17. Gluconeogenesis takes place predominantly in the A. muscles B. brain C. heart D. pancrease E. liver  18. Biotin functions as a: A. carrier of activated aldehydes B. carrier of activated carbon dioxide C. carrier of activated electrons D. carrier of activated acyl groups  19. What are the most important products that cells generate by means of the pentose phosphate pathway? A. lactate and ATP B. ribose-5-phosphate and NADPH C. NADP+ and ribose-5-phosphate D. NADPH and UDP-ribose E. ribulose-1,5-bisphosphate and NADPH  20. Which combination of cofactors is involved in the conversion of pyruvate to acetyl-CoA? A. NAD+, biotin, and TPP, and Co A B. TPP, Co A, lipoic acid, NAD+ and FAD C. pyridoxal phosphate, FAD and lipoic acid, D. biotin, FAD, and TPP E. biotin, NAD+, and FAD  21. In a eukaryotic cell, the enzymes of glycolysis are located in the ____ and the enzymes of the TCA cycle are located in the ____: A???????? plasma membrane, cytosol. B???????? cytosol, mitochondrial matrix. C???????? cytosol, mitochondrial matrix and membrane. D???????? nucleus, cytosol.  22. Which of the following compound is responsible for coordinated regulation of glycolysis and gluconeogenesis? A???????? NADH B???????? acetyl-CoA C???????? fructose 2,6 bis phosphate D???????? fructose 1,6 bis phosphate  23.A lack of phosphoglucomutase activity is most likely to produce a deficiency of A. pyruvate B. ribose 5-phosphate C. NADP D. NADH E. glycogen  24. Approximately 10% of the glucose derived from glycogen and released from the liver during fasting is produced directly (not generated via the action of glucose-6-phosphatase) by which of the following enzymes? A. Glycogen phosphorylase B. Debranching enzyme C. Branching enzyme D. Glycogen synthase E. UTP/glucose 1-phosphate pyrophosphorylase  25. Which if the following enzymes forms alpha-1, 6 linkages in glycogen? A. glycogen phosphorylase B. glycogen branching enzyme C. amylo-(1,6) glucosidase D. phosphorylase kinase E. glucose 6-phosphatase  26. Which enzyme is present in the liver but NOT in the muscle? A. hexokinase B. glucose 6-phosphatase C. lactate dehydrogenase D. pyruvate dehydrogenase E. glycogen phosphorylase  27. Gluconeogenesis from lactate does not require activity of A. aldolase B. phosphofructokinase C. glyceraldehyde 3-phosphate dehydrogenase D triose phosphate isomerase E. phosphoglycerate kinase  28. Which compound does NOT contribute to the net formation of glucose during gluconeogenesis in humans? A. propionate B. glycerol C. acetyl-CoA D. lactate E. alanine  29. Which of the following describes the mechanism by which NADH generated in the cytoplasm donates electrons to oxygen via the mitochondrial electron transport system? A. A specific transport system enables NADH to pass through the mitochondrial membrane. B. NADH reduces cytoplasmic FAD to FADH2, which passes through the mitochondrial membrane. C. NADH reduces cytoplasmic dihyroxyacetone phosphate to glycerol phosphate, which is reoxidized by an enzyme associated with the mitochondrial electron transport system. D. NADH reduces cytoplasmic NADP to NADPH, which can enter the mitochondria. E. None of the above mechanism is used.  30. Mammals cannot achieve a NET synthesis of glucose from fatty acids due to the inability to convert A. acetyl-CoA to acetoacetate. B. acetyl-CoA to pyruvate. C. oxaloacetate to pyruvate. D. acetyl-CoA to malonyl CoA. E. methylmalonyl-CoA to succinyl-CoA.  31. The immediate products of oxidation of one mole of glucose 6-phosphate through the oxidative portion of the pentose phosphate pathway are: A. one mole of ribulose 5-phosphate, one mole of CO2 and two moles of NAD. B. one mole of ribulose 5-phosphate, one mole of CO2 and two moles of NADPH. C. one mole of xylulose 5-phosphate, one mole of CO2 and two moles of NADPH. D. one mole of ribose 5-phosphate, one mole of CO2 and two moles of NADPH. F.????? one mole of fructose 6-phosphate and two moles of NADP. 32. The enzyme transketolase is a component of A. the TCA cycle. B. the pentose pathway. C. fatty acid synthase. D. the pyruvate dehydrogenase complex. E. none of the above  33. Glycolysis A.???? Takes place in the mitochondrion B.???? Is the major provider of ATP to muscle during heavy exercise C.???? Is controlled by levels of fructose-2,6 bis phosphate D.???? Is the only pathway known from glucose to pyruvate  34. Glycogen phosphorylase A.???? Responds oppositely to epinephrine in liver and muscle B.???? Is phosphorylated by protein kinase A C.???? Has an R and T form that are stabilized by AMP and ATP, respectively D.???? Is phosphorylated in response to cyclic AMP and Ca2+  35. The citric acid cycle A.???? Oxidizes acetate to CO2 and water B.???? Provides intermediates for amino acid, porphyrin and carbohydrate biosynthesis C.???? Can accomplish net synthesis of succinate from acetylCoA D.???? Can be replenished by carboxylation of PEP  36. Which one of the following statements about gluconeogenesis in animal cells is true? A?????? the conversion of glucose-6-phosphate to glucose is catalyzed by hexokinase. B?????? the conversion of phosphoenolpyruvate to 2-phosphoglycerate occurs in two steps, including a carboxylation. C?????? the conversion of fructose-1,6-bisphosphate to fructose-6-phosphate is not catalyzed by phosphofructokinase, the enzyme involved in glycolysis. D?????? an animal fed a large excess of fat in the diet will convert any fat not needed for energy E??????? production into glycogen for later use. F??????? gluconeogenesis helps to reduce blood glucose after a carbohydrate-rich meal.  37. Which of the following is true of glucagon (in liver) and epinephrine (in muscle)? A???????? they both activate glycogen phosphorylase and inactivate glycogen synthase. B???????? they both inhibit glycogen synthesis and activate glycogen breakdown. C???????? they act by raising the concentration of cAMP. D???????? they oppose the effects of insulin on these tissues. E????????? all of the above.  38. Phosphorylation activates all of the following except: A???????? glycogen phosphorylase B???????? phosphoprotein phosphatase inhibitor C???????? phosphoprotein phosphatase D???????? triacylglycerol lipase E????????? phosphorylase kinase  39. A common moiety for NADP, NAD, FMN, FAD, and coenzyme A is: A.????? A pyrimidine ring; B.????? A three ring structure; C.????? An ADP; D.???? A pyranose ring; E.????? A triphosphate group.  40. If the C-1 carbon of glucose were labeled with 14C, which of the carbon atoms in pyruvate would be labeled after glycolysis? A.????? The carboxylate carbon; B.????? The carbonyl carbon; C.????? The methyl carbon.  41. Which of the following are metabolic products of pyruvate in higher organisms? A.????? Glycerol B.????? Lactic acid C.????? Acetone D.???? Acetyl-CoA E.????? Ethanol  42. Indicate whether each of the following statements about the pentose phosphate pathway is true A.????? It generates NADH for reductive biosyntheses. B.????? The reactions occur in the cytosol. C.????? Transketolase and transaldolase link this pathway to gluconeogenesis. D.???? It is more active in muscle cells than in fat-storage cells. E.????? It interconverts trioses, tetroses, pentoses, hexoses, and heptoses.  43. Which of the following statements are correct? The citric acid cycle A.????? does not exist as such in plants and bacteria, because its functions are performed by the glyoxylate cycle. B.????? oxidizes acetyl CoA derived from fatty acid degradation. C.????? produces most of the CO2 in anaerobic organisms. D.???? provides succinyl CoA for the synthesis of carbohydrates. E.????? provides precursors for the synthesis of glutamic and aspartic acids.  44.Indicate whether each of the following statements about the glyoxylate cycle is true A. It allows the products of fatty acid oxidation to be converted, eventually, to glucose. B. It provides intermediates for the citric acid cycle during periods when amino acids are being synthesized. C. It depletes cellular stores of oxaloacetate. D. It occurs instead of the citric acid cycle in plants.  45.Which statement is NOT true of phosphofructokinase-1? A.???? It is inhibited by fructose-2,6-bisphosphate. B.???? It is activated by AMP. C.???? It is inhibited by citrate. D.???? It is inhibited by ATP. E.????? ATP increases its K0.5 for fructose 6-phosphate.  46.All of the following statements describe glycolysis EXCEPT: A.???? It produces a net of 2 ATP molecules for each molecule of glucose. B.???? Its rate is mainly regulated by hexokinase. C.???? The glycolytic enzymes are found in the cytosol. D.???? Two molecules of glyceraldehydes 3-phosphate are produced for each glucose molecule. E.????? Its overall rate is regulated by the energy level of the cell.  47. A lack of phosphoglucomutase activity is most likely to produce a deficiency of A. pyruvate B. ribose 5-phosphate C. NADP D. NADH E. glycogen  48.Which of the following statements is not correct about the reactions catalyzed by pyruvate dehydrogenase? A. It is a multienzyme complex that catalyzes 5 reactions using 3 enzymes and 5 cofactors. B. TPP , lipoamide and FAD are tightly associated with the enzyme complexes C. The purpose of reactions 4 and 5 is to recycle the cofactors D. The extended side chain of the prosthetic group lipoamide moves between the various active sites allowing the transfer of intermediates between the three enzymes. F.All of the statements are correct concerning pyruvate dehydrogenase  49.Which of the following statements is TRUE of muscle glycogen phosphorylase? A. It degrades glycogen to form glucose-1-phosphate. B. It removes glucose residues from the non-reducing ends of glycogen chains. C. It catalyzes phosphorolysis of ?(1?6) bonds of glycogen. D. All of the above are correct concerning muscle glycogen phosphorylase E. None of the above are correct concerning muscle glycogen phosphorylase  50. Gluconeogenesis is the synthesis of: A. glucose from non-carbohydrate precursors B. glycogen from glucose C. pyruvate from glucose D. fatty acids from glucose  51. Which of the following enzymes catalyzes a REVERSIBLE reaction in vivo? A. hexokinse B. pyruvate kinase C. phosphoglycerate kinase D. phosphofructokinase E. None of these enzymes catalyze a reversible reaction in vivo.  52. The glycogen synthase uses _____ as the substrate for glycogen synthesis, A. glucose-1-phosphate B. UDP-glucose C. glucose-6-phosphate D. glucose  53. The primary regulatory enzyme for glycolysis is: A. glycogen phosphorylase B. hexokinase C. phosphofructokinase D. phosphoglucomutase  54. Which of the following statements about NAD+ and FAD is correct? A. Each can accept 2 electrons, 1 electron at a time. B. Each can accepts electrons only in 2 electron transfers C. NAD+ accepts only 2 electrons at a time while FAD can accept 1 electron at a time. D. FAD accepts only 2 electrons at a time while NAD+ can accept 1 electron at a time. E. None of the statements are correct.  55. Which of the following is the central intermediate that links several carbohydrate metabolic pathways? A. glucose B. glucose 1-phosphate C. glucose 6-phosphate D. UDP-glucose E.glucose 1, 6 bisphosphate  5 ※<21> Chloroplasts A????????? Contain a variety of pigments to be able to intercept most of the photons in visible light B????????? Have one more internal compartment than mitochondria (the thylakoid) C????????? Contain as many reaction centers as chlorophyll molecules D???????? Have the chlorophyll mainly in the outer membrane (grana membranes)  2. Photosynthetic reaction centers A????????? Contain only chlorophyll and protein B????????? Have a series of electron carriers to remove the excited electron from the special pair before the energy can be lost by fluorescence C????????? Move the electron from the excited chlorophyll from one side of the membrane to the other D???????? Are uniformly distributed in the grana stacks and grana lamellae  3. The Calvin cycle A????????? Converts 3 CO2 to glyceraldehyde-3P B????????? Uses transketolase and transaldolase in the same way as the pentose phosphate pathway to convert glyceraldehyde-3P back to ribulose-5P (no transaldolase) C????????? Is controlled by, among other things, the redox level of the chloroplast D???????? Is inhibited by the high pH that results when photophosphorylation leads to proton pumping, so the dark reactions only occur in the dark  5. The Calvin cycle of photosynthetic carbon fixation A????????? Carboxylates the 5 carbon ribulose bis phosphate to the 6 carbon fructose bis phosphate B????????? Regenerates the ribulose bis phosphate with a series of transketolase and aldolase reactions C????????? Has two sugar bis phosphatase reactions with large negative G values D???????? Has to take place in different cells from the light reactions of photosynthesis2.  6. Which of the following statements about the light reactions in photosynthetic plants is false? A????????? There are two distinct photosystems, linked together by an electron transport chain. B????????? A membrane-bound ATPsynthase couples ATP synthesis to electron transport. C????????? The ultimate source of electrons for the process is H2O. D???????? The ultimate electron acceptor is O2 . E????????? No CO2 is fixed in the light reactions.  7.Carbon fixation involves a condensation reaction between CO2 and: A????????? 3-phosphoglycerate. B????????? Phosphoglycolate. C????????? Ribulose 1,5-bisphosphate. D???????? Fructose 6-phosphate. E????????? Ribose 5-phosphate.  8.Which of the following statements about photosystem II is correct. A????????? It is located in the inner mitochondrial membrane. B????????? It contains the electron carrier with the most negative E`o in the entire photosynthetic system.. C????????? It contains an Mn-containing complex that splits water. D???????? Its final electron acceptor is NADP+. E????????? H2O is the only electron donor capable of regenerating P680 from P680*.  5 ※<22> 1. Hepatic fatty acid oxidation is suppressed in the well-fed state because A????????? carnitine levels are too low B????????? fatty acids are converted poorly to their CoA esters C????????? fatty acid synthase activity is high D???????? malonyl-CoA levels are high E????????? NAD+ concentrations are limiting  2. The conversion of palmitoyl-CoA to stearyl-CoA requires A????????? △9 desaturase B????????? fatty acid synthase C????????? malonyl-ACP (acyl carrier protein) D???????? NAD+ E????????? NADPH  5. The common metabolic intermediate that is shared by both metabolism of glucose and fatty acids is: A???????? oxaloacetate. B???????? lactic acid. C???????? ethanol. D???????? acetyl-CoA  6. Fatty acid synthesis A???????? Occurs in the mitochondria B???????? Uses a 3-carbon precursor to put in two carbons (malonyl CoA) C???????? In eukaryotes takes place on a multienzyme complex D???????? Is a simple reversal of ?-oxidation  7. Odd chain fatty acids A???????? Undergo the same -oxidation process as even-chain fatty acids B???????? Are glycogenic C???????? Require B12 for their complete oxidation D???????? Are transported into the mitochondrion as CoA esters  8. The following fatty acid, in which the indicated carbon is labeled with 14C, is fed to an animal:14CH3(CH2)9COOH.After allowing 30 min for fatty acid oxidation only to occur, the label would most likely be recovered in: A???????? acetyl-CoA B???????? propionyl-CoA C???????? palmitoyl-CoA D???????? carnitine E????????? CO2  9. Matching the role in fatty acid oxidation and/or mobilization to the appropriate component listed below. A.????? Bile salt: B.????? Serum albumin: C.????? ApoC-II: D.???? Apolipoprotein: E.????? Carnitine: 1). Acts as a “carrier” of fatty acids across the inner mitochondrial membrane. 2). Acts as a biological detergent, disrupting fat globules into small mixed micelles. 3). Binds and transports triacylglycerols, phospholipids, and cholesterol between organs. 4). Activates lipoprotein lipase, which cleaves triacylglycerols into their components. 5). Binds some fatty acids molibized from adipocytes and transports them in the blood to heart and skeletal muscle.  10. Which of the following are common features of the syntheses of mevalonate (an intermediate of cholesterol biosynthesis) and ketone bodies? A????????? Both involve 3-hydroxyl-3-methylglutaryl CoA (HMG-CoA). B????????? Both require NADPH. C????????? Both require the HMG-CoA cleavage enzyme. D???????? Both occur in the mitochondria. E????????? Both occur in liver cells.  11.A sample of malonyl-CoA synthesized from radioactive (14C-labeled) HCO3- and unlabeled acetyl-CoA is used in fatty acid synthesis. In which carbon(s) will the final fatty acid be labeled? (Recall that the carboxyl carbon of the fatty acid is C-1) A???????? Every carbon. B???????? Every odd-numbered carbon. C???????? Every even-numbered carbon. D???????? Only the carbon farthest from C-1. E????????? No part of the molecule will be labeled.  12.Which of the following statements about cholesterol synthesis is not true? A???????? Reduction of HMG-CoA to mevalonate catalyzed by HMG-CoA reductase is the committed step. B???????? Acetyl-CoA is the ultimate source of all 27 carbon atoms of cholesterol. C???????? It is inhibited by elevated levels of intracellular cholesterol. D???????? It is hormonally inactivated by glucagons and activated by insulin. E????????? It occurs in the mitochondrial matrix  13.All of the following enzymes are linked to the reduction of NADH except: A???????? Isocitrate dehydrogenase. B???????? Lactate dehydrogenase. C???????? Succinate dehydrogenase. D???????? Pyruvate dehydrogenase. E????????? ?-ketoglutarate drhydrogenase.  14.Place the following steps in lipid oxidation in their proper sequence. (Note: this is not a complete list of steps.) A???????? Thiolysis. B???????? Reaction of fatty acyl-CoA with carnitine. C???????? Oxidation requiring NAD+. D???????? Hydrolysis of triacylglycerol by lipase. E????????? Activation of fatty acid by joining to CoA. F????????? Hydration.  5 ※<23> 1.Elevated plasma concentrations of the α-ketoacids produced by transamination of leucine, isoleucine, and valine could result from A????????? defect in dihydrobiopterin reductase B????????? defect in the aminotransferase for leucine, isoleucine, and valine C????????? defect in the branched-chain α-ketoacid dehydrogenase complex D???????? deficiency of pyridoxal phosphate E????????? overproduction of these ketoacids from fatty acids  2. Which of the following answers complete the sentence correctly? Surplus dietary amino acids may be converted into A????????? proteins. B????????? Fats. C????????? ketone bodies. D???????? glucose. E????????? a variety of biomolecules for which they are precursors.  3. Nitrogen fixation A???????? Is the only significant source of nitrogen in forms that can be used by organisms B???????? Requires iron and molybdenum C???????? Proceeds with the production of H2 D???????? Involves various phosphorylated derivatives of nitrogen  4. Glutamine synthetase in E. coli A???????? Is controlled by covalent modification B???????? Is only required to make the glutamine needed for protein synthesis C???????? Is almost completely inhibited by carbamoyl phosphate D???????? Is modified by an enzyme whose activity is controlled by modification 5. The aspartate family of amino acids (lysine, methionine and threonine) A???????? Are synthesized by mammals B???????? Have transamination as the final step in their synthesis C???????? Use three different aspartokinases, each controlled by a different final product D???????? Go through aspartic semialdehyde  6. Amino acid degradation A???????? Usually starts with transamination B???????? Can lead to carbohydrate synthesis C???????? In mammals, uses the urea cycle to dispose of excess ammonia D???????? Uses the same reactions as synthesis, but in reverse  7. Porphyrins A???????? Are synthesized from glycine and succinylCoA in animals B???????? Are formed by spontaneous cyclization of the linear tetrapyrrole precursor, to give the symmetric product C???????? Are major constituents of heme, chlorophyll and B12 D???????? Are degraded in mammals to CO2 and NH3  8. Which of the following compounds serves as an acceptor for the amino groups of many amino acids during metabolism? A????????? Glutamine B????????? Asparagine. C????????? ?-ketoglutarate. D???????? Oxaloacetate E????????? Glutamate  9. Match the functions for the coenzymes that are involved in amino acid metabolism. A.????? Pyridoxal phosphate: B.????? Coenzyme B12: C.????? Tetrahydrobiopterin: D.???? NAD+: E.????? Biotin 1). Carries electrons 2). Provides free radicals 3). Carries amino groups 4). Carries CO2.  10. S-adenosylmethionine is involved directly in which of the following reactions. A????????? Methyl transfer to phosphatidyl ethanolamine. B????????? Synthesis of glycine from serine. C????????? Synthesis of polyamines. D???????? Conversion of homocysteine to methionine. E????????? Generation of the 5` cap of the eukaryotic mRNAs. 11.Which of the following does not provide a carbon skeleton for the synthesis of amino acids? A????????? succinate. B????????? ?-ketoglutarate C????????? Pyruvate. D???????? Oxaloacetate. E????????? Ribose-5-phosphate.  12. Biosynthetic pathways that require NADPH include which of the following? A????????? Gluconeogenesis. B????????? Fatty acid biosynthesis. C????????? Ketone body formation. D???????? Cholesterol biosynthesis. E????????? Tyrosine biosynthesis.  13.Which of the following is not true of nitrogen fixation by the nitrogenase complex? A???????? This enzyme complex is inactivated by exposure to oxygen. B???????? ATP binding causes a change in the conformation of the reductase moiety. C???????? The primary role of ATP is to drive nitrogen fixation through the hydrolysis of PPi. D???????? Nitrogen fixation occurs only in prokaryotes. E????????? The final electron acceptor in this process in N2.  14.Which of the following is a characteristic of many aminotransferase reactions? A???????? They have a large, negative (G`o. B???????? The amino group is transferred to an ?-keto acid (such as ?-ketoglutarate) to form the corresponding amino acid. C???????? The amino group is transferred from an ammonia molecule. D???????? They are catalyzed by the same enzyme. E????????? They require the cofactor  15.S-adenosylmethionine Early in its life, a tadpole lives in an aqueous environment and excretes much of its excess nitrogen as ammonia. Once it matures into an adult, the frog spends more time on dry land and becomes ureotelic. Which of the following enzyme activities would be most likely to increase drastically in the adult frog? A???????? Carbamoyl phosphate synthetase I. B???????? Glutamine synthetase. C???????? glutaminase. D???????? carboxypeptidase. ?-ketoglutarate dehydrogenase  5 ※<24> 1. Which statement is FALSE concerning therapeutics used for treatment of metabolic disorders? A.???? Vitamin D analogues are used to prevent rickets in children. B.???? Allopurinol inhibits hypoxanthine:guanosine phosphoribosyl transferase and is used in the treatment of gout C.???? Pernicious anemia can be caused by a lack of “intrinsic factor”, which then requires intravenous treatment with Vitamin B12. D.???? Megaloblastic anemia results from deficiencies in some folic acid reaction and is thus treated with folate analogues that are substrates after the enzyme reaction block. E.????? Severe Combined Immunodeficiency Disease (SCID) is frequently caused by an error in adenosine deaminase, which is usually treated by gene therapy.  2. Purine nucleotides A.???? Are built up on phosphoribosyl pyrophopsphate B.???? Are synthesized through inosine C.???? Acquire methyl groups from S-adenosyl methionine D.???? Must be converted to triphosphates before inosine can be made into guanine  3. Which of the following compounds directly provide atoms to form the purine ring? A.???? Aspartate. B.???? Carbamoyl phosphate. C.???? Glutamine. D.???? Glycine. E.????? CO2. F.????? N5,N10-methylenetetrahydrofolate. G.???? N10-formyltetrahydrofolate. H.???? NH4+.  4. Which of the following statements about ribonucleotide reductase are true? (2 points) A.???? It converts ribonucleoside diphosphates into 2`-deoxyribonucleoside diphosphates in humans. B.???? It contains coenzyme B12, which generates free radicals needed for the catalysis. C.???? It accepts electrons directly from FADH2. D.???? It receives electrons directly from either thioredoxin or glutaredoxin. E.????? It contains two kinds of allosteric regulatory sites: one for controlling the overall activityand the other for controlling the substrate specificity.  5.In nucleotide metabolism, all of the following are true except: A.???? The committed step in purine biosynthesis is the transfer of an amino group to PRPP. B.???? Both purine and pyrimidine biosynthesis are regulated by end-product inhibition. C.???? Nucleotide can be synthesized in a single reaction via salvage pathways. D.???? De novo pyrimidine synthesis begins with a molecule of PRPP. E.????? Orotidylate is the common precursor in the biosynthesis of pyrimidines, and inosinate is the common precursor in the biosynthesis of the purines ATP and GTP.  5 ※<25> 1. DNA replication is a highly coordinated event that requires many protein factors. A???????? DNA gyrase introduces negative supercoils during prokaryotic DNA replication. B???????? DNA polymerase I is responsible for lagging strand DNA synthesis, whereas DNA polymerase III holoenzyme is mainly needed for leading strand DNA synthesis. C???????? Two ??subunits of the bacterial DNA polymerase III holoenzyme are required to form a DNA clamp on each DNA strand. D???????? The ??subunit of DNA polymerase III holoenzyme has the proofreading activity. E????????? Primase is required to remove the RNA primers made during DNA replication.  2. DNA repair is essential for correcting the damage occurring on DNA molecules. A???????? ?a. DNA photolyase can bind and also cleave thymine dimers induced by UV light. B???????? A 14-nucleotide DNA fragment is released by uvrABC endonuclease during the mismatch repair process. C???????? MutS, MutL, and MutH are involved in the nucleotide excision repair in E. coli. D???????? Recombinational repair can occur either before or after DNA replication. E????????? Binding of RecA to single-stranded DNA stimulates LexA self-cleavage during the SOS response.  3. Which of the following does NOT participate in DNA replication? A???????? helicase B???????? single stranded binding protein C???????? transcription factor D???????? ligase E????????? primase  4. DNA replication is a ______________ process. A???????? conservative b. destructive B???????? non-conservative d. semi-conservative C???????? 5. DNA replication proceeds in the 5’->3’ direction. However, in e. coli replication proceeds in both directions from the initial replication site. This 3’->5’ replication still proceeds in a 5’->3’ manner with the use of short DNA fragments called..... D???????? helicase fragments b. Okazaki fragments E????????? single strand binding proteins c. Primer fragments  6. DNA replication requires the use of RNA primers. What is the primary reason for this? A???????? to provide a 3’ OH group for DNA polymerase to use. B???????? to provide a 5’ OH group for DNA polymerase to use. C???????? to provide a 3’ phosphate group for DNA polymerase to use. D???????? to provide a 5’ phosphate group for DNA polymerase to use. 6. Which of the following is NOT a characteristic of bacterial plasmids? A???????? Useful cloning vectors B???????? DNA molecules which are linear C???????? Self-replicating, extrachromosomal DNA molecules D???????? Closed circles in structure  5 ※<26> 1. RNA processing is necessary to generate mature mRNAs in eukaryotes.