Chapter 15- Glucose Catabolism – Flashcards

In the glycolytic pathway ATP is synthesized by which one of the following methods? Entry field with correct answer Oxidative phosphorylation Photophosphorylation Phosphorolysis Substrate-level phosphorylation

What is the typical fate of pyruvate in red blood cells? Entry field with correct answer Completely oxidized to CO2 and H2O. Converted to ethanol and CO2. Reduced to produce lactate. Used to produce glucose via gluconeogenesis.

Which one of the following is not involved in the reactions of glycolysis between glyceraldehyde-3-phosphate and 3-phosphoglycerate? Entry field with correct answer Generation of ATP. Use of inorganic phosphate. Catalysis by a kinase enzyme. The formation of a high energy intermediate. Oxidation of NADH.

Which of the following combinations correctly identifies net production when 1 mol of fructose 6-phosphate is converted to pyruvate during glycolysis? Assume that re-oxidation of NADH via the electron transport chain yields the equivalent of 3 ATP, and that re-oxidation of FADH2 yields 2 ATP. Entry field with correct answer 1 mol of NAD+ and 3 mol of ATP 2 mol of NADH and 2 mol of ATP 2 mol of NADH and 3 mol of ATP 1 mol of NADH and 2 mol of ATP 2 mol of NAD+ and 3 mol of ATP

Which of the following identifies net production when 1 mol of fructose-1,6-bisphosphate is converted to 2 mol of lactate? Assume that re-oxidation of NADH via the electron transport chain yields the equivalent of 3 ATP, and that re-oxidation of FADH2 yields 2 ATP. Entry field with correct answer 4 mol of ATP 4 mol of ATP + 2 mol of NADH 2 mol of ATP 2 mol of ATP + 2 mol of NADH

Which of the following statements about the reaction catalyzed by hexokinase is FALSE? Entry field with correct answer Hexokinase is competitively inhibited by its product. Hexokinase desolvates glucose to speed up the rate of the reaction. Hexokinase undergoes a conformational change when glucose binds at the active site. Hexokinase catalyses a substrate-level phosphorylation reaction.

Which statement completes the following sentence correctly? The reactions in glycolysis catalyzed by phosphofructokinase-1 and pyruvate kinase are similar in that: Entry field with correct answer they are both catalyzed by allosteric enzymes. they are both reversible. they both involve three-carbon compounds. they are both substrate-level phosphorylation reactions. they both use ATP.

Which of the following is a high-energy intermediate produced in glycolysis? Entry field with correct answer 2-PG GAP 1,3-BPG Phosphocreatine F-1,6-BP

What is the net energy gain when 1 molecule of dihydroxyacetone phosphate is converted to pyruvate? Entry field with correct answer 1 mol of NADH + 1 mol of ATP 2 mols of NADH + 4 mols of ATP 1 mol of NADH + 2 mols of ATP 1 mol of NADH + 4 mols of ATP 2 mols of NADH + 2 mols of ATP

Pyruvate has several metabolic fates depending on the cell, under aerobic or anaerobic conditions. Which one of the following is a metabolic fate for pyruvate? Entry field with correct answer oxidative carboxylation to acetyl-CoA reduction to lactate decarboxylation to oxaloacetate oxidation to ethanol

The rate of glucose consumption in yeast is dramatically different if the yeast are grown in the presence of oxygen as compared to yeast grown under anaerobic conditions. What would this difference be? Entry field with correct answer Yeast grown anaerobically consume 10 times less glucose. Yeast grown anaerobically consume 19 times less glucose. Yeast grown anaerobically consume 10 times more glucose. Yeast grown anaerobically consume 19 times more glucose.

Which one of the following enzymes catalyzes an "energy investment" reaction in glycolysis? Entry field with correct answer A. Hexokinase B. Phosphofructokinase-2 C. Pyruvate kinase D. Phosphoglycerate kinase Both A and B are correct.

Which of the following statements is TRUE regarding the glycolytic pathway? Entry field with correct answer The energy capture steps are all substrate-level phosphorylation reactions. The balanced equation for glycolysis is: Glucose + 2ADP + 2Pi ------> 2 pyruvate + 2H+ + 2ATP + 2H2O. The pathway is regulated by allostery and product inhibition among other things. Some reactions of glycolysis occur in the cytosol and some occur in the mitochondrial matrix.

In the oxidation reaction of glycolysis, which of the following statements is TRUE? Entry field with correct answer Some of the energy of the REDOX reaction is conserved in formation of 1,3-BPG. ATP is consumed in the reaction. It is an irreversible reaction. It is a regulated step of glycolysis. During the catabolism of glucose to pyruvate, NAD+ is oxidized.

Which of the following is a reversible reaction under cellular conditions? Entry field with correct answer Phosphoenolpyruvate + ADP + H+ -----> Pyruvate + ATP 1,3-bisphosphoglycerate + ADP ------> 3-phosphoglycerate + ATP Fructose-6-phosphate + ATP ------> Fructose-1,6 bisphosphate + ADP + H+ Glucose-6-phosphate + H2O -----> Glucose + Pi

Which of the following represents the balanced equation of the energy payout/capture phase of glycloysis? Entry field with correct answer GAP + NAD+ + 2ADP + Pi ----> pyruvate + NADH + 2ATP + H+ GAP + 2NAD+ + 2ADP + 2Pi ---> pyruvate + 2NADH + 2ATP + 2H2O GAP + 2NAD+ + 4ADP + 2Pi ----> pyruvate + 2NADH + 4ATP + 2H+ + 2H2O GAP + NAD+ + 2ADP + Pi ----> pyruvate + NADH + 2 ATP + H2O + H+

If radioactively labeled inorganic phosphate (32Pi) is added to a cell-free liver extract, which of the following molecules will become radiolabeled during glycolysis? Entry field with correct answer A. Phosphoenolpyruvate B. glyceraldehyde-3-phosphate C. 1,3-bisphosphoglycerate D. ATP Both C and D are correct.

If pyruvate could not be converted to lactate in muscle cells during strenuous exercise, what would be the outcome? Entry field with correct answer Glycolysis would be more efficient. Glycolysis would stop. The muscle cell would export pyruvate out of the cell. The rate of gluconeogenesis will increase.

Which of the following is a cofactor for the enzyme glyceraldehyde-3-phosphate dehydrogenase? Entry field with correct answer NAD+ ATP ADP Pi

What is the most likely fate of pyruvate in mammalian muscle during very vigorous exercise? Entry field with correct answer Conversion to oxaloacetate, to replenish citric acid cycle intermediates via anaplerotic reactions. Conversion to acetyl-CoA via the pyruvate dehydrogenase complex. Transport out of the muscle cell into the bloodstream. Conversion to lactate via lactate dehydrogenase.

Which one of the following enzymes catalyzes a substrate-level phosphorylation reaction in the catabolism of glucose? Entry field with correct answer hexokinase glyceraldehyde-3-phosphate dehydrogenase pyruvate kinase phosphofructokinase-1

Which one of the following does NOT occur in the reactions of glycolysis between glucose and fructose-1,6-bisphosphate? Entry field with correct answer Formation of a high energy intermediate. Product inhibition of an enzyme. An isomerization. Phosphoryl transfer.

What is the biochemical purpose for the production of lactate in muscle cells? Entry field with correct answer It decreases the pH of the muscle cell, thereby increasing release of oxygen from hemolglobin. Its production enhances the activity of the citric acid cycle. It is produced as a fuel molecule for the Cori cycle. It replaces pyruvate as a substrate for the pyruvate dehydrogenase complex. It is produced to reoxidize cytoplasmic NADH under anaerobic conditions

Biochemically, why is ethanol produced by yeast? Entry field with correct answer Ethanol replaces acetyl-CoA as the main substrate for the citric acid cycle. The accumulation of acetaldehyde, which is toxic, is prevented. Its production facilitates the transport of reducing equivalents into the mitochondria. Cytoplasmic NADH is reoxidized sustaining glycolysis under anaerobic conditions.

Glucose is converted to ______ in skeletal muscle under anaerobic conditions. Entry field with correct answer lactate acetyaldehyde fructose glycogen acetyl-CoA

Aerobic glycolysis produces a net yield of ______ ATP. Entry field with correct answer 1 2 3 4 more than 4

Which of the following enzymes catalyzes the transfer of a phosphoryl group from ATP to glucose? Entry field with correct answer hexokinase phosphoglucose isomerase glucose-6-phosphatase phosphoglucose mutase A transfer such as this does not occur in glycolysis.

The enzymes that catalyze glycolysis are located in the Entry field with correct answer endoplasmic reticulum. mitochondrial matrix. cytosol. inner mitochondrial membrane. outer mitochondrial membrane.

The enzyme _____forms a Schiff base upon formation of the enzyme-substrate complex allowing aspartate mediated cleavage of the substrate. Entry field with correct answer hexokinase phosphoglucose isomerase glucose-6-phosphatase phosphoglucose mutase aldolase

In alcoholic fermentation, acetaldehyde is produced by Entry field with correct answer the decarboxylation of pyruvate. the carboxylation of pyruvate. the decarboxylation of lactate. the carboxylation of lactate. none of the above

Glycolytic synthesis of ATP occurs via Entry field with correct answer oxidation. reduction. substrate-level phosphorylation. oxidative phosphorylation. photophosphorylation.

Experimental evidence indicates that glyceraldehyde-3-phosphate dehydrogenase contains a critical ______ residue in its active site, as shown by its inactivation by iodoacetamide. Entry field with correct answer alanine aspartate cysteine methionine lysine

Which is the net equation for aerobic glycolysis? Entry field with correct answer Glucose + 2 ATP 2 lactate + 2 ADP + 2 Pi Glucose + 2 ADP + 2 Pi + 2 NAD+ 2 pyruvate + 2 ATP + 2 NADH + 2 H2O + 4 H+ Glucose + 2 ADP + 2 Pi 2 lactate + 4 ATP + 4 H+ Glucose + 2 ATP + 2 NAD+ 2 pyruvate + 4 ATP + 4 NADH + 4 H+ Glucose + 2 ADP + 2 Pi + 2 NAD+ 2 lactate + 4 ATP + 2 NADH + 4 H+

In which of the following metabolic conversions is ATP required during glycolysis? I. fructose-6-phosphate fructose-1,6-bisphosphate II. glucose glucose-6-phosphate III. fructose-1,6-bisphosphate dihydroxyacetone phosphate + glyceraldehyde-3-phosphate IV. glucose-6-phosphate fructose-6-phosphate Entry field with correct answer I only II only I, II I, III I, IV

During glycolysis, the steps between glucose and formation of the triose phosphates collectively Entry field with correct answer consume two ATP and two NADH molecules. consume two ATP molecules. produce two ADP and two NADH molecules. produce two ATP and two NAD+ molecules. consume two NAD+ molecules.

In skeletal muscle cells, oxidation of NADH generated from anaerobic glycolysis occurs during which of the following reactions? Entry field with correct answer acetaldehyde ethanol lactate pyruvate phosphoenolpyruvate pyruvate pyruvate lactate glyceraldehyde-3-phosphate 1,3-bisphosphoglycerate

Which of the following metabolic conversions is considered to be the major control point of glycolysis? Entry field with correct answer fructose-1,6-bisphosphate dihydroxyacetone phosphate + glyceraldehyde-3-phosphate glucose glucose-6-phosphate 2-phosphoglyerate phosphoenolpyruvate fructose-6-phosphate fructose-1,6-bisphosphate phosphoenolpyruvate pyruvate

If glucose labeled at the C-1 position with 14C passes through glycolysis, on which carbon of pyruvate will the radiolabel be found? Entry field with correct answer 1 2 3 It will be released in CO2 rather than present in pyruvate. Not enough information is given to predict.

Which glycolytic enzyme catalyzes a reaction with an enediolate intermediate? Entry field with correct answer phosphoglucomutase triose phosphate isomerase phosphofructokinase aldolase none of the above

Which of the following is true regarding glycolysis? I. There is a net oxidation of substrate carbon atoms. II. There is no net release of free energy. III. Pyruvate is generated only during aerobic glycolysis. IV. There is 2 ATP formed for every 2 glucose molecules. Entry field with correct answer I only I, IV I, III, IV IV only II, IV

The reaction catalyzed by the enzyme aldolase has a ≈ +23 kJ/mol. In muscle cells, the reaction proceeds in this same, forward direction. How can this occur? Entry field with correct answer This means it is thermodynamically favored. The enzyme changes the of the reaction in cells to something favorable. The concentration of reactant(s) must be significantly greater than product(s) in cells. The concentration of product(s) must be significantly greater than reactant(s) in cells. None of the above.

Methanol is highly toxic, not because of its own activity, but because it is converted metabolically into formaldehyde, which is the actual poison. What enzyme catalyzes this conversion? Entry field with correct answer methanol caboxylase methanol transferase alcohol transmutase alcohol carboxylase alcohol dehydrogenase

Which of the following reactions does not occur in mammals? Entry field with correct answer pyruvate + NADH lactate + NAD+ ribulose-5-phosphoate ribose-5-phosphate mannose + ATP mannose-6-phosphate + ADP + Pi 6-phophogluconate + NADP+ ribulose-5-phosphate + NADPH + CO2 pyruvate + NADH + H+ CO2 + ethanol + NAD+

Which enzyme is involved in substrate level phosphorylation in glycolysis? Entry field with correct answer Hexokinase Pyruvate kinase Glyceraldehyde-3-phosphate dehydrogenase Aldolase None of the above.

During reactions utilizing the enzymes shown below, in which case(s) is ATP produced? I. phosphofructokinase (PFK) II. phosphoglycerate kinase (PGK) III. pyruvate kinase (PK) Entry field with correct answer I II III I, II II, III

In which reaction below is ATP required? I. 1,3-Bisphosphoglycerate (BPG) 3-phosphoglycerate(3PG) II. Glucose glucose-6-phosphate (G6P) III. 2-Phosphoglycerate (2PG) 3-phosphoglycerate (3PG) IV. Glycerol-3-phosphate (GAP) 1,3-Bisphosphoglycerate (BPG) V. Glucose-6-phosphate (G6P) fructose-6-phosphate (F6P) Entry field with correct answer I, II II only III only IV, V None of the reactions I-V requires ATP.

In which reaction below is at least 1 NADH formed? I. 1,3-Bisphosphoglycerate (BPG) 3-phosphoglycerate (3PG) II. Glucose glucose-6-phosphate (G6P) III. 2-Phosphoglycerate (2PG) 3-phosphoglycerate (3PG) IV. Glyceraldehyde 3-phosphate (GAP) 1,3-Bisphosphoglycerate (BPG) V. Glucose-6-phosphate (G6P) fructose-6-phosphate (F6P) Entry field with correct answer II only III only IV only IV, V None of the reaction I-V form NADH.

Which of the following identifies net production when 1 mol of glucose is converted to 2 mol of lactate? Assume that re-oxidation of NADH via the electron transport chain yields the equivalent of 3 ATP, and that re-oxidation of FADH2 yields 2 ATP. Entry field with correct answer 1 mol of ATP. 2 mol of ATP and 2 mol of NADH. 2 mol of ATP and 1 mol of NADH. 2 mol of ATP.

How is lactate transported out of the muscle and how does it help hemoglobin to release oxygen? Entry field with incorrect answer By a lactate/H+ symporter, which lowers the blood pH. By a lactate/H+ antiporter, which raises the blood pH. By a lactate/H+ antiporter, which lowers the blood pH. By a lactate/H+ symporter, which raises the blood pH. The transport of this H+ into the bloodstream lowers blood pH.