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21. If the standard free energy change, b.Go', for the transformation A B is positive. then: A. The reaction will go to the right under all conditions. B. The reaction will go to the right, starting from 1M concentrations each of A and B. e. The equilibrium constant is greater than l. D. The reaction will go to the left, starting from standard conditions. E. The equilibrium constant is negative.

d

34. The activity of glycogen phosphorylase in muscle is affected pri- marily by: A glucagon B. melanocyte stimulating hormone C. adrenocorticotropic hormone D. epinephrine E. somatostatin.

d

36. Which one of the following is a gluconeogenic enzyme? A. glucose-6-phosphate dehydrogenase B. phosphoglucomutase C. phosphofructokinase D. pyruvate carboxylase E. lactate dehydrogenase.

d

55. Increased concentration of galac- tose-I-P. A glucose-6-P dehydrogenase deficiency B. glucose-6-phosphatase deficiency C. galactokinase deficiency D. UDP-galactose epimerase deficiency E. hexokinase deficiency

d

A man is in negative nitrogen balance when his: A. dietary nitrogen drops below the recommended daily allowance B. fecal nitrogen excretion exceeds his urinary nitrogen excretion C. diet contains more nonessential amino acids than essential amino acids D. urinary nitrogen excretion exceeds his dietary nitrogen intake E. dietary nitrogen intake exceeds his urinary nitrogen excretion.

d

A patient presenting with a suspected metabolic disorder shows (1) abnormally high amounts of glycogen with normal structure in liver, and (2) no increase in blood glucose levels following oral administration of fructose. From these two findings, which one of the following enzymes is likely to be deficient? A. phosphoglucomutase B. UDP-glycogen transglucosylase C. fructokinase D. glucose-6-phosphatase E. glucokinase.

d

Activated form of glucose utilized by glycogen synthetase. A. Glucose-I-phosphate B. Glucose-6-phosphate C. Glucose-l,6-bisphosphate D. UDP-glucose

d

Addition of cyanide to a tightly-coupled mitochondrial system causes: A. increase in electron transport, inhibition of A TP formation B. decrease in electron transport, increase in ATP formation C. decrease in electron transport with a compensatory increase in the Krebs Cycle D. decrease in the Krebs Cycle, electron transport, and A TP formation E. decrease in electron transport only.

d

All of the following are "high-energy" compounds EXCEPT: A. CTP B. ATP C. CH3CO-SCoA D. glucose-6-phosphate E. phosphoenol pyruvate.

d

Cannot be converted to glucose. A glucose-6-phosphate B. UDP-galactose C. lactate D. acetyl CoA E. 1,3-bisphosphoglycerate

d

Cofactors involved in the regeneration of methionine from homo- cysteine include: A lipoic acid B. retinoic acid C. biotin and thiamin pyrophosphate D. co factors derived from tetrahydrofolic acid and vitamin B12 E. cofactors derived from vitamins E and K.

d

Glucagon: A has actions similar to those of insulin B. is secreted by the beta cells of the pancreatic islets C. increases triglyceride concentrations in many tissues D. targets liver primarily E. targets muscle primarily.

d

Hyaluronic acid is a: A. glycoprotein B. high molecular weight, positively charged polysaccharide C. polymer which contains sulfate D. repeating disaccharide of glucuronic acid and N-acetyl glucosamine E. lipoprotein.

d

Phenylketonuria is a genetic defect caused by absence of: A a-keto acid decarboxylase B. tyrosinase C. homogentisic acid oxidase D. phenylalanine hydroxylase E. alanine transaminase.

d

Phosphofructokinase. A A TP is a substrate B. A TP is an inhibitor C. AMP is an inhibitor D. ATP is both a substrate and an inhibitor

d

Regulates pyruvate carboxylase. A glucose-6-phosphate B. UDP-galactose C. lactate D. acetyl CoA E. 1,3-bisphosphoglycerate

d

Starting materials for the reactions catalyzed by the pyruvate dehydrogenase complex include all of the following (A - D) EXCEPT: If all are included, no exception, choose E. A. NAD+ B. CoA e. pyruvate D. ADP E. all of the above without exception.

d

The first step in the gluconeogenic pathway (starting with pyru- vate) results in the formation of: A. phosphoenolpyruvate B. malate C. aspartate D. oxaloacetate E. lactate.

d

The increase of glycogenolysis in muscle produced by epinephrine may be attributed to: A decreased Ca++ B. activation of aldolase C. reduction in total NAD+ plus NADH D. conversion of phosphorylase b to phosphorylase a E. conversion of glycogen synthase b to glycogen synthase a.

d

The term "oxidative phosphorylation" refers to a process in which: A ATP energy is used to drive protons across the inner mitochon- drial membrane. B. A proton gradient provides power for electron transfer from sub- strate to oxygen. e. A TP energy supplies power for transfer of electrons from sub- strate to oxygen. D. Electron transfer from substrate to oxygen provides energy to create a proton gradient, which then powers synthesis of A TP. E. Phosphorylation of ADP creates a pH gradient across the inner mitochondrial membrane.

d

What is the NET yield of ATP when glucose l-phosphate is oxi- dized by anaerobic glycolysis to lactate? AD B. 1 C. 2 D. 3 E. 4

d

Which of the following enzyme pairs is involved in the conversion of amino acid nitrogen into two compounds that directly provide the urea nitrogen? A. glutamic-oxaloacetic transaminase and diamine oxidase B. L-amino acid oxidase and racemase C. serine dehydratase and glutamate dehydrogenase D. carbamoyl phosphate synthetase and glutamic-oxaloacetic transaminase E. glutamine synthetase and glutaminase.

d

Which one of the following carbohydrates contains a monosac- charide unit other than glucose? A glycogen B. cellulose C. maltose D. lactose E. starch

d

Which one of the following enzymes is inhibited by an accumula- tion of NADH? A aldolase B. enolase C. pyruvate kinase D. glyceraldehyde 3-phosphate dehydrogenase E. pyruvate decarboxylase.

d

Which one of the following is a ketose? AD-glucose B. D-ribose C. D-galactose D. D-fructose E. N -acetylgl ucosamine.

d

Which one of the following is an essential amino acid? A asparagine B. glycine C. glutamic acid D. methionine E. serine.

d

Which one of the following statements concerning the pentose phosphate pathway is true? A NADH is a major product of the oxidative branch. B. The entire pathway is "off' when NADPH levels are high C. It is not present in brain tissue. D. When glucose 6-phosphate dehydrogenase is inhibited by one of its products, ribose 5-phosphate biosynthesis still occurs. E. It provides an alternative pathway for the synthesis of glucose from glyceroL

d

Which one of the following statements regarding gluconeogenesis is INCORRECT? A. Glucose can be synthesized from non-carbohydrate precursors. B. Gluconeogenesis is not a reversal of glycolysis. C. Gluconeogenesis and glycolysis are reciprocally regulated. D. Lactate and alanine formed by contracting muscle are converted into glucose in muscle. E. Six high energy phosphate bonds are spent in synthesizing one molecule of glucose from pyruvate.

d

Which one of the following sugars is found exclusively 10 gly- cosaminoglycans? A N-acetylglucosamine B. N -acetylgalactosamine C. sialic acid D. L-iduronic acid E. L-arabinose.

d

hellohe immediate products of oxidation of one mole of glucose 6- phosphate through the oxidative portion of the pentose phosphate pathway are: A. 2 moles of reduced NAD, one mole of ribulose 5-phosphate and one mole of CO2 B. 2 moles of oxidized NADP, one mole of ribulose 5-phosphate and one mole of CO2 C. 2 moles of reduced NADP, one mole of xylulose 5-phosphate and one mole of CO2 D. 2 moles of reduced NADP, one mole of ribulose 5-phosphate and one mole of CO2 E. one mole of fructose 6-phosphate and five moles of CO2•

d

If a mature animal in nitrogen balance is placed on a diet deficient only in phenylalanine, which of the following conditions is most likely to occur? A. Nitrogen balance will become negative and remain that way so long as the deficiency exists. B. Nitrogen balance will become negative temporarily, but the indi- vidual will adapt and N balance will gradually return to zero. C. Nitrogen intake will continue to equal nitrogen excretion (balance = 0). D. Nitrogen balance will become positive and remain that way so long as the deficiency exists. E. Nitrogen balance will become positive temporarily, but the indi- vidual will adapt and N balance will gradually return to zero.

a

If a pure crystal of ,B-D-glucose is dissolved in water and left in solution for a long period of time, it is likely that the solution will contain: A the open-chain form of D-glucose, a-D-glucose, and ,B-D-glucose B. the open-chain form of D-glucose and ,8-D-glucose C. a-D-glucose and ,B-D-glucose only D. a-D-glucose only E. ,B-D-glucose only.

a

In hereditary fructose intolerance, the primary biochemical defect is: A. a deficiency in activity of an aldolase isozyme B. increased allosteric sensitivity of phosphofructokinase to AMP C. inhibition of glycogen synthetase D. an inability to absorb fructose E. a deficiency in the activity of fructokinase.

a

In mitochondria treated with the uncoupler DNP (dinitrophenol), the number of ATP derived from the oxidation of one NADH is: A. 0 B. 1 C. 2 D. 3 E. 6

a

Products of the reactions catalyzed by the pyruvate dehydroge- nase complex include all of the following (A - D) EXCEPT: If all are included, no exception, choose E. A. lactate B. NADH e. acetyl CoA D. CO2 E. all of the above without exception.

a

Regulates glycogen synthase. A glucose-6-phosphate B. UDP-galactose C. lactate D. acetyl CoA E. 1,3-bisphosphoglycerate

a

Sucrose is: A. a disaccharide containing glucose and fructose B. a reducing disaccharide of plant origin C. a disaccharide containing glucose and galactose D. a fructose polymer E. a product of digestion of cellulose.

a

The P/O ratio for NADH + H+ produced in the Krebs Cycle is: A 3 B. 2 C. 1 D. 0 E. -1

a

The utilization of ammonia for synthesis of the a-amino group of non-essential amino acids: A. is dependent on the action of glutamate dehydrogenase B. is achieved by reversal of the urea cycle C. is mediated by carbamoyl phosphate D. is dependent on intestinal bacteria E. requires the participation of glutamine.

a

Which one of the following enzymes is found mainly in liver and kidney cells? A glucose 6-phosphatase B. hexokinase C. phosphoglucoisomerase D. pyruvate kinase E. glycogen synthase.

a

Which one of the following glycogen storage diseases does NOT involve a defect in the glycogen degradation pathway? A Type I (von Gierke's Disease) B. Type IV (Andersen's Disease) C. Type VI (Hers' Disease) D. Type V (McArdle's Disease) E. Type III (Cori's Disease).

a

glucokinase A A TP is a substrate B. A TP is an inhibitor C. AMP is an inhibitor D. ATP is both a substrate and an inhibitor

a

57. Increased concentration of liver glycogen. A glucose-6-P dehydrogenase deficiency B. glucose-6-phosphatase deficiency C. galactokinase deficiency D. UDP-galactose epimerase deficiency E. hexokinase deficiency

b

A nine-carbon acid found as the non-reducing termini of oligosac- charide side chains of many glycoproteins is: A hyaluronic acid B. sialic acid C. iduronic acid D. glucuronic acid E. gluconic acid.

b

Amylose is: A a branched homopolysaccharide B. a linear homopolysaccharide C. a linear heteropolysaccharide D. a salivary enzyme E. a pancreatic enzyme.

b

Biotin is required as a coenzyme in which one of the following reactions? A a-ketoglutarate + NAD+ + CoA -+ succinyl CoA + CO2 +NADH B. pyruvate + CO2 + ATP -+ oxaloacetate + ADP + Pi C. pyruvate + NAD+ + CoA -+ acetyl CoA + C02 + NADH D. 6-phosphogluconate -+ ribulose-5-phosphate + CO2 E. a-ketoglutarate + alanine ;:! glutamate + pyruvate.

b

Dopamine is a neurohormone in brain. Its precursor is: A. cysteine B. phenylalanine C. asparagine D. tryptophan E. lysine.

b

Given the process: +2 w x -3 o y z with standard free energy changes in Kcallmole as shown, what is the standard free energy change for the process Z -+ W? A -1 Kcallmole B. +1 Kcallmole e. 0 Kcallmole D. +2 Kcallmole E. -2 Kcallmole.

b

Glucagon has which one of the following effects on glycogen metabolism in the liver? A. The net synthesis of glycogen is increased. B. Glycogen phosphorylase is activated, whereas glycogen synthase is inactivated. C. Both glycogen phosphorylase and glycogen synthase are activated. D. Glycogen phosphorylase is inactivated, whereas glycogen synthase is activated. E. Phosphoglucomutase is phosphorylated.

b

Glyceraldehyde-3-phosphate dehydrogenase produces which one of the following as a product? A dihydroxyacetone phosphate B. 1,3-bisphosphoglyceric acid C. glycerol D. phosphoenolpyruvic acid E. NADPH.

b

Glycolysis in the red blood cell produces: A. citric acid B. NADH C. GTP D. CO2 E. glucose-1-phosphate.

b

In a patient suffering from Type III glycogen storage disease, an abnormal glycogen exhibiting short outer branches is observed. Which enzyme is most likely to be defective? A. glycogen synthase B. amylo-l,6-glucosidase ( debranching enzyme) C. glycogen phosphorylase D. phosphoglucomutase E. UDP-glucose pyrophosphorylase.

b

In mammals glucose 6-phosphate is converted to all of the fol- lowing compounds EXCEPT: A glucose B. fructose 1-phosphate C. 6-phosphogluconolactone D. fructose 6-phosphate E. glucose 1-phosphate.

b

In the metabolism of glycerol to glycogen, the first intermediate of glycolysis encountered is: A glyceraldehyde-3-phosphate B. dihydroxyacetone phosphate C. 3-phosphoglyceric acid D. ribulose-5-phosphate E. 1,3-bisphosphoglyceric acid.

b

The Cori Cycle: glucose -> 2 lactate + 2 ATP (muscle), and 2 lactate + 6 ATP -> glucose (liver) is important because: A. there is a net destruction of ATP, restoring the energy balance between muscle and liver. B. it results in the net generation of glucose in liver and ATP in mus- cles without build up of high lactate levels in the bloodstream. e. it enables muscle mass to be used for energy in conditions of extreme starvation. D. it serves to prevent lactate levels from dropping too low in the blood, which would impair brain function. E. it enables G-6-P to be transported across the liver cell plasma membrane.

b

The catabolism of 1 mole of glucose in the glycolytic pathway under anaerobic conditions results in the formation (or NET gain) of: A 1 mole of UDP-galactose B. 2 moles of A TP + 2 moles of lactic acid C. 1 mole of glucose-l,6-diphosphate D. 6 moles of CO2 + 6 moles of H20 E. 1 mole of ethanol + 1 mole of lactic acid.

b

The most significant role of the oxidative portion of the hexose monophosphate shunt is the generation of: A hexose monophosphate from free hexose B. NADPH C. NAD+ D. ATP from ADP and Pi E. UDP-gluconic acid from UDP-glucose.

b

There are three irreversible steps in glycolysis. These are: A. hexokinase, phosphoglycerate kinase, and pyruvate kinase B. hexokinase, phosphofructokinase, and pyruvate kinase C. phosphofructokinase, aldolase, and phosphoglyceromutase D. phosphoglucose isomerase, glyceraldehyde 3-phosphate dehydro- genase, and enolase E. triose phosphate isomerase, phosphoglycerate kinase, and enolase.

b

Which one of the following statements regarding glycogen metabolism is INCORRECT? A. Glycogen consists of a-l,4-glycosidic bonds and a-l,6-glycosidic bonds. B. Glycogen phosphorylase catalyzes the hydrolytic cleavage of glycogen into glucose-l-phosphate. e. A debranching enzyme is needed for the complete breakdown of glycogen. D. Phosphoglucomutase converts glucose-l-phosphate into glucose- 6-phosphate. E. Glycogen is synthesized and degraded by different pathways.

b

Which one of the following substrates can NOT contribute to net gluconeogenesis in mammalian liver? A. alanine B. stearate C. a-ketoglutarate D. glutamate E. pyruvate.

b

45. Sialic acid is: A found only in mammalian tissues B. the major carbohydrate found in heparin C. a normal constituent of glycoproteins D. an -carboxyl amino acid E. a cofactor for neuraminidase.

c

Activated sugar residues utilized for the biosynthesis of complex glycoproteins include all EXCEPT: A. GDP-mannose B. GDP-fucose C. UDP-glucuronic acid D. CMP-N-acetylneuraminic acid E. UDP-galactose.

c

After complete metabolism of one molecule of glucose to CO2 and H20 through 2 whole turns of the Krebs Cycle, the amount of oxaloacetate in the mitochondrion will be: A. increased by two molecules B. increased by one molecule e. unchanged D. decreased by one molecule E. decreased by two molecules.

c

All of the following are high energy compounds EXCEPT: A phosphoenolpyruvate B. acetyl-CoA C. glucose 6-phosphate D. acetyl phosphate E. creatine phosphate.

c

All of the following statements about phosphofructokinase (PFK) are true EXCEPT: A it is a major control enzyme in glycolysis B. ATP is a substrate for PFK C. fructose 2,6-bisphosphate is a negative effector of PFK D. ATP is a negative effector of PFK E. it catalyzes a metabolically irreversible reaction; i.e., its equilib- rium point lies far in one direction.

c

An allosteric inhibitor of phosphofructokinase is: A. a-ketoglutarate B. oxaloacetate C. citrate D. isocitrate E. succinate.

c

Coenzyme for phosphogluco- mutase. A. Glucose-I-phosphate B. Glucose-6-phosphate C. Glucose-l,6-bisphosphate D. UDP-glucose

c

Essentially benign excretion of a glucose epimer A glucose-6-P dehydrogenase deficiency B. glucose-6-phosphatase deficiency C. galactokinase deficiency D. UDP-galactose epimerase deficiency E. hexokinase deficiency

c

Fructose-l,6-bisphosphatase. A A TP is a substrate B. A TP is an inhibitor C. AMP is an inhibitor D. ATP is both a substrate and an inhibitor

c

In the tricarboxylic acid cycle, four oxidation - reduction reactions produce reducing equivalents. The word that characterizes the name of the enzyme in all four cases is: A. oxidase B. reductase C. dehydrogenase D. isomerase E. synthetase

c

The absence of which one of the following reactions is responsible for the inability of man to use fatty acids in the de novo net synthesis of glucose? A. oxaloacetate -> pyruvate B. oxaloacetate + acetyl CoA -> citrate C. acetyl CoA -> pyruvate D. pyruvate -> phosphoenolpyruvate E. phosphoenolpyruvate -> oxaloacetate.

c

The combination of which of the following enzymatic activIties provides the major route of flow of nitrogen from amino acids to ammonia in man? A. amino acid oxidases and glutamate dehydrogenase B. glutamate dehydrogenase and glutaminase C. transaminases and glutamate dehydrogenase D. transaminases and glutaminase E. glutaminase and amino acid oxidases.

c

The major rate-limiting step of glycolysis is the: A. conversion of glucose to glucose 6-phosphate B. conversion of glucose 6-phosphate to fructose 6-phosphate C. conversion of fructose 6-phosphate to fructose 1,6-bisphosphate D. aldolase reaction E. epimerase reaction.

c

The major site of carbohydrate digestion is: A. mouth B. stomach C. small intestine D. large intestine E. pancreas.

c

The most general definition of oxidation is: A. addition of oxygen B. removal of oxygen C. removal of electrons D. addition of hydrogen E. removal of hydrogen.

c

The number of residues bound by glycosidic linkages to a glucose residue that forms a branch point in glycogen is: A 1 B. 2 C. 3 D. 4 E. 5

c

The tissue with the lowest activity for the oxidation of glucose-6- phosphate by the pentose phosphate pathway is: A liver B. lactating mammary gland C. striated muscle D. adrenal cortex E. adipose tissue.

c

Transketolase requires which one of the following coenzymes? A pyridoxal phosphate B. lipoamide C. thiamin pyrophosphate D. cobalamin E. tetrahydrofolic acid.

c

Transport of amino acids by thegamma-glutamyl cycle involves direct participation of which one of the following components? A GTP B. aspartic acid C. glutathione D. glutamine E. glucose.

c

Under normal conditions, most regions of the inner mitochondrial membrane are impermeable to: A. O2 B. CO2 C. H+ D. H 20 E. N2

c

Von Gierke's disease is characterized by massive enlargement of the liver, severe hypoglycemia, ketosis, hyperuricemia and hyper- lipemia. It is caused by defective: A. amylo-a-l,6 glucosidase B. branching enzyme (a-l,4 -> a-l,6) C. glucose 6-phosphatase D. a-l,4 glucosidase E. phosphorylase.

c

Which one of the following is a glycolytic enzyme of liver and is activated by protein phosphate phosphatase in response to decreasing glucagon levels? A. glycogen synthetase B. glycogen phosphorylase C. pyruvate kinase D. triose phosphate isomerase E. lactate dehydrogenase.

c

56. Increased lipid peroxides in ery- throcytes. A glucose-6-P dehydrogenase deficiency B. glucose-6-phosphatase deficiency C. galactokinase deficiency D. UDP-galactose epimerase deficiency E. hexokinase deficiency

a

A state of high "energy charge" would: A. inhibit glycolysis, pyruvate dehydrogenase, and citrate synthase. B. stimulate glycolysis and pyruvate dehydrogenase, but inhibit citrate synthase. C. inhibit glycolysis and citrate synthase, but stimulate pyruvate de- hydrogenase. D. stimulate glycolysis, pyruvate dehydrogenase, and citrate synthase. E. stimulate glycolysis, pyruvate dehydrogenase, citrate synthase, and the mitochondrial A TP synthase.

a

An amino acid which is both ketogenic and glucogenic is: A tyrosine B. alanine C. leucine D. glutamic acid E. histidine.

a

An example of an oxidation - reduction reaction is: A. malate + NAD+ -+ oxaloacetate + NADH + H+ B. succinyl-CoA + GDP + Pj -+ succinate + GTP C. acetyl CoA + oxaloacetate -+ citrate + CoA D. fumarate + H20 -+ malate E. ATP + H20 -+ ADP + Pj

a

Epinephrine (in muscle) and glucagon (in liver): A. activate adenylate cyclase B. inactivate phosphorylase and activate glycogen synthetase C. stimulate triglyceride synthesis D. stimulate glycogen synthesis E. act synergistically with insulin.

a

Galactosemia is caused by A a deficiency of galactose-1-phosphate uridyltransferase B. a deficiency of UDP-galactose 4-epimerase C. the high content of lactose in artificial feeding formulae for babies D. absorption of non-hydrolyzed lactose through the intestinal mucosa E. excessive conversion of glucose-1-phosphate into galactose-l- phosphate.

a

Generated during breakdown of glycogen by glycogen phosphorylase. A. Glucose-I-phosphate B. Glucose-6-phosphate C. Glucose-l,6-bisphosphate D. UDP-glucose

a

Glucose, labeled with 14C in different carbon atoms is added to a tissue that is rich in the enzymes of the hexose monophosphate shunt. Which one will give the most rapid initial production of 14C02? A. glucose-1-14C B. glucose-2-14C C. glucose-3,4_14C D. glucose-5-14C E. glucose-6-14C.

a

During starvation, as gluconeogenesis increases to maintain the levels of blood glucose, which one of the following will be enhanced? A. liver pyruvate kinase activity B. the secretion of insulin by the pancreas C. muscle phosphoglucomutase activity D. the metabolism of acetyl CoA to pyruvate E. the metabolism of glutamate to glucose-6-phosphate.

e

How many high-energy phosphates are generated through the complete metabolism of one acetyl (CoA) unit to CO2 and H20? A. 1 B. 3 C. 6 D. 11 E. 12

e

In a biological situation, the "criterion of spontaneity" that allows one to predict whether a reaction will proceed, is: A. AGo' B. AEo' C. standard free energy change D. energy of activation E. AG

e

In aerobic metabolism most of the high-energy phosphate is gen- erated by: A. glycolysis acting on glycogen and generating lactate B. glycolysis acting on glucose and generating pyruvate C. the pyruvate dehydrogenase reaction D. the Krebs Tricarboxylic Acid Cycle E. protons passing through the Fo - Fl complex.

e

In glucose 6-phosphate dehydrogenase deficiency, increased red cell lysis is ultimately due to: A. problems with A TP production in mitochondria B. a deficiency in ability to carry out glycolysis C. increased leakage of K ion into the cells D. an intrinsic deficiency of membrane structure E. inability of the cell to maintain normal levels of NADPH.

e

The enzyme aldolase catalyzes the: A. formation of fructose-6-phosphate from glucose-6-phosphate B. oxidation of the aldehyde group of glucose C. oxidation of the aldehyde group of glyceraldehyde-3-phosphate D. conversion of glyceraldehyde-3-phosphate to dihydroxyacetone- phosphate E. formation of dihydroxyacetone phosphate and glyceraldehyde-3- phosphate from fructose-1,6-bisphosphate.

e

The immediate driving force that powers the phosphorylation of ADP to ATP by ATP synthase is: A. high [ADP] in the mitochondrion B. high [NADH] in the cytoplasm c. gradient of A TP across the inner mitochondrial membrane D. gradient of glucose across the plasma membrane E. gradient of H + across the inner mitochondrial membrane.

e

The rate-limiting reaction in the urea cycle is that catalyzed by: A. argininosuccinase B. argininosuccinate synthetase C. arginase D. ornithine transcarbamoylase E. carbamoyl phosphate synthetase.

e

The tricarboxylic acid cycle can do many wondrous things. One thing it can NOT do is: A. be part of the pathway that converts carbons of glucose to the carbon skeleton of glutamate B. metabolize the carbon skeleton of aspartate to CO2 C. be part of the pathway that converts the carbon skeleton of glutamate to glucose D. contribute to metabolizing a majority of the carbons of glucose to CO2 E. provide part of the pathway for net synthesis of glucose from fat.

e

Which one of the following is changed by the presence of an enzyme? A. fiG B. flGo' C. Keq D. the position of the equilibrium, expressed as concentration of products/reactants E. the time required to reach equilibrium.

e