CHAPTER NINE AEROBIC METABOLISM I 1 Place the following reaction intermediates of the citric acid cycle in chronological order i malate ii fumarate iii succinylCoA iv citrate v ketoglutarate 2 Oxalosuccinate is a transient intermediate formed during which of the following reactions A i ii iv v iii B iv v iii i ii C iv i v iii ii D v iii i ii iv E iv v iii ii i Ans E A Citrate Isocitrate B Isocitrate ketoglutarate C Pyruvate Acetyl CoA D Malate Oxaloacetate E Succinyl CoA Succinate Ans B A Pyruvate Acetyl CoA B Malate Oxaloacetate C SuccinylCoA Succinate D Succinate Fumarate E Succinate Malate Ans D A Malate Fumarate B Succinate Fumarate 3 FADH2 is a product of which of the following reactions 4 NADH is produced in which of the following reactions 5 In the glyoxylate cycle two carbon molecules are converted to precursors of which of the following C Ketoglutarate SuccinylCoA D SuccinylCoA Fumarate E Oxaloacetate Citrate Ans C A Acetyl CoA B Glucose C Pyruvate D Succinate E Carbon dioxide Ans B A Aconitase B Malate dehydrogenase C Fumarase D Succinate dehydrogenase E Isocitrate lyase Ans E A Malate dehydrogenase B Fumarase C Citrate lyase D Ketoglutarate dehydrogenase E Succinate thiokinase Ans D 6 Which of the following enzymes is unique to the glyoxylate cycle 7 The regulated enzymes of the citric acid cycle include 8 The enzymes involved in citrate metabolism include all of the following except A Citrate synthase B Citrate lyase C Pyruvate carboxylase D Malate synthase E Malic enzyme Ans D 9 Redox potential is best defined as A The tendency of one species to gain electrons B The tendency of one species to lose electrons C The tendency of a species to gain or lose electrons D The entropy of a reaction expressed as a voltage difference E None of the above is correct Ans C Ans B 10 In order to determine the standard voltage of a reaction A The individual reaction reduction potentials must be added B The standard cells must be written as they occur in the reaction and the voltages are added C All the reactions must be written as oxidations and the voltages are added D The voltages of the individual reactions at pH 7 must be calculated and the resultant voltages are added E A standard voltage for a reaction must be determined experimentally 11 Which of the following reactions is an oxidation reaction A NaOH HCl NaCl H2O B CH3COOH CH3COO H C CH3CHO CH3CH2OH D CH3CH2OH CH3CHO E CH2 CH2 H2O CH3CH2OH 12 Which of the following reactions has an oxidized product A Carboxylic acid aldehyde B R SH RSH R S S R C Alcohol Ketone Wrong answer on the answer key here this is oxidized D Glutamate Ketoglutarate E None of the above are correct Ans D Ans E 13 In any redox reaction an electron donor is A The reducing agent B The oxidizing agent C Reduced as it accepts electrons D All of the above are correct E None of the above are correct Ans A 14 In a redox reaction an electron acceptor is A Oxidized as it accepts one or more electrons B The reducing agent C Converted to an electron donor with the gain of one or more electons D All of the above are correct E None of the above are correct Ans C 15 Each turn of the citric acid cycle produces how many moles of CO2 16 Acetyl CoA that is consumed by the citric acid cycle is produced from which of the following biochemical pathways A 1 B 2 C 3 D 4 E 5 Ans B A Glycolysis B Fatty acid oxidation C Purine catabolism D Urea cycle E Both A and B are correct Ans E A FADH2 0 22V B H2 0 424V C Cytochrome a Fe 2 0 29V D Lactate 0 19 V E H2O 0 82V Ans B A Succinate B Oxaloacetate 17 Which of the following is the strongest reducing agent The standard reduction potential of each species is provided in parentheses 18 Which of the following reacts with acetylCoA to form citrate 19 The redox reaction in which succinate is converted to fumarate uses FAD rather than NAD because A FAD is a stronger oxidizing agent than NAD B NAD is a stronger oxidizing agent than FAD C FAD is required for the oxidation of carboxylic acids D Only FAD can penetrate into mitochondria E NAD is not found in the cytoplasm 20 Most of the energy released during the electron transport system is used to drive synthesis C Ketoglutarate D Fumarate E Malate Ans B Ans A A ATP B ADP C NADH D NADPH E Fatty acids Ans A 21 Which of the following reactions requires GDP A Fumarate Malate B SuccinylCoA Succinate C Malate Oxaloacetate D Citrate Isocitrate E Ketoglutarate Succinyl CoA Ans B 22 How many oxidations steps are there in the citric acid cycle 23 The product of the first reaction of the citric acid cycle is A 1 B 2 C 3 D 4 E 5 Ans D A Acetyl CoA B Oxaloacetate C Pyruvate D Lactate E Citrate Ans E A Pyruvate AcetylCoA B Succinyl CoA Succinate C Citrate Isocitrate D Fumarate Malate E Malate Oxaloacetate Ans B 24 Which of the following reactions involves a substrate level phosphorylation 25 The carbon skeletons of which of the following are direct precursors of amino acids A Malate 26 Which of the following is not directly required for the activity of pyruvate dehydrogenase 27 Which of the following is a positive effector of isocitrate dehydrogenase B Succinate C Ketoglutarate D Oxaloacetate E Both C and D are correct Ans E A CoASH B Lipoic acid C NAD D ATP E None of the above are correct Ans D A ADP B FAD C NADH D Succinyl CoA E Both A and C are correct Ans A 28 Consider the following reaction Pyruvate NADH H Lactate NAD The half cell reaction with their standard reduction potentials are Pyruvate 2H 2e Lactate 0 19V NAD H 2e NADH 0 32V What is the reduction potential for the overall reaction A 0 00V B 0 03 V C 0 13 V D 0 22 V E 0 15 V Ans C Ans C 29 The overall reaction catalyzed by pyruvate dehydrogenase is which of the following A CH3COCHO NAD CoASH CH3CHOSCoA NADH B CH3COCOO FAD CoASH CH3CHSCoA NADH C CH3COCOO NAD CoASH CH3COSCoA NADH D CH3CH OH COO NADH CoASH CH3CH OH COSCoA NAD E None of the above is correct 30 The citric acid cycle is a component of aerobic respiration Molecular oxygen A Is directly involved in the reactions of the cycle B Is only indirectly involved in the reactions of the cycle C Is an important substrate for the cycle D Both A and C are true E None of the above are true 31 The main toxic effect of oxygen is due to which of the following 32 The primordial reductive branch of the citric acid cycle was a means of producing which of …