Chapter1 Introduction to Metabolism quiz1

1、 问题:Which one below is NOT a kind of high energy compound?
选项:
A:ATP
B:G-6-P
C:Glycerate-1,3-bisphosphate
D:Phosphocreatine
答案: 【G-6-P

2、 问题:Enzymes are potent catalysts because they:
选项:
A:are consumed in the reactions they catalyze.
B:are very specific and can prevent the conversion of products back to substrates.
C:increase the equilibrium constants for the reactions they catalyze.
D:lower the activation energy for the reactions they catalyze.
答案: 【lower the activation energy for the reactions they catalyze.

3、 问题:Which statement about allosteric control of enzymatic activity is FALSE?
选项:
A:Allosteric effectors give rise to sigmoidal V versus [S] kinetic plots.
B:An effector may either inhibit or activate an enzyme.
C:Binding of the effector changes the conformation of the enzyme molecule.
D:Heterotropic allosteric effectors compete with substrate for binding sites.
答案: 【Heterotropic allosteric effectors compete with substrate for binding sites.

4、 问题:A small molecule that DECREASES the activity of an enzyme by binding to a site other than the catalytic site is termed a(n):
选项:
A:allosteric inhibitor.
B:alternative inhibitor.
C:competitive inhibitor.
D:stereospecific agent.
答案: 【allosteric inhibitor.

5、 问题:Which amino acid is NOT one that may be targeted for phosphorylation to modulate the activity of an enzyme?
选项:
A:Tyr
B:Ser
C:Ala
D:Thr
答案: 【Ala

6、 问题:Which type of enzyme is responsible for attaching phosphate groups to specific amino acids?
选项:
A:a protein phosphatase
B:a protein kinase
C:a protein glycosylase
D:an ATPase
答案: 【a protein kinase

Chapter2 Carbohydrate Metabolism quiz2

1、 问题:Which reaction in glycolysis requires ATP as a substrate?
选项:
A:hexokinase
B:glyceraldehyde-3-phosphate dehydrogenase
C:pyruvate kinase
D:aldolase
答案: 【hexokinase

2、 问题:Which reaction in glycolysis produces ATP as a product?
选项:
A:hexokinase
B:glyceraldehyde-3-phosphate dehydrogenase
C:pyruvate kinase
D:phosphofructokinase-1
答案: 【pyruvate kinase

3、 问题:During strenuous exercise, the NADH formed in the glyceraldehyde 3-phosphate dehydrogenase reaction in skeletal muscle must be reoxidized to NAD+ if glycolysis is to continue. The most important reaction involved in the reoxidation of NADH is:
选项:
A:dihydroxyacetone phosphate → glycerol 3-phosphate.
B:pyruvate → lactate.
C: isocitrate → α-ketoglutarate.
D:oxaloacetate → malate.
答案: 【pyruvate → lactate.

4、 问题:The anaerobic conversion of 1 mol of glucose to 2 mol of lactate by fermentation is accompanied by a net gain of:
选项:
A: 1 mol of ATP.
B:1 mol of NADH.
C: 2 mol of ATP.
D:2 mol of NADH.
答案: 【 2 mol of ATP.

5、 问题:In comparison with the resting state, actively contracting human muscle tissue has a:
选项:
A: higher concentration of ATP.
B:higher rate of lactate formation.
C:lower consumption of glucose.
D:lower rate of consumption of oxygen
答案: 【higher rate of lactate formation.

6、 问题:Which compound CANNOT serve as the starting material for the synthesis of glucose via gluconeogenesis?
选项:
A:acetate
B:glycerol
C:lactate
D:oxaloacetate
答案: 【acetate

7、 问题:An enzyme used in both glycolysis and gluconeogenesis is:
选项:
A:3-phosphoglycerate kinase.
B:glucose 6-phosphatase.
C:hexokinase.
D:phosphofructokinase-1.
答案: 【3-phosphoglycerate kinase.

8、 问题:Which statement about gluconeogenesis is FALSE?
选项:
A:For starting materials, it can use carbon skeletons derived from certain amino acids.
B:It consists entirely of the reactions of glycolysis, operating in the reverse direction.
C:It employs the enzyme glucose 6-phosphatase.
D:It is one of the ways that mammals maintain normal blood glucose levels
答案: 【It consists entirely of the reactions of glycolysis, operating in the reverse direction.

9、 问题: In humans, gluconeogenesis:
选项:
A:can result in the conversion of protein into blood glucose.
B:helps to reduce blood glucose after a carbohydrate-rich meal.
C:is essential in the conversion of fatty acids to glucose.
D:requires the enzyme hexokinase.
答案: 【can result in the conversion of protein into blood glucose.

10、 问题:Which statement about the pentose phosphate pathway is CORRECT?
选项:
A:It generates 36 mol of ATP per mole of glucose consumed.
B:It is a reductive pathway; it consumes NADH.
C: It is present in plants, but not in animals.
D: It provides precursors for the synthesis of nucleotides.
答案: 【 It provides precursors for the synthesis of nucleotides.

11、 问题:The metabolic function of the pentose phosphate pathway is to:
选项:
A:act as a source of ADP biosynthesis.
B:generate NADPH and pentoses for the biosynthesis of fatty acids and nucleic acids.
C:participate in oxidation-reduction reactions during the formation of H2O.
D:provide intermediates for the citric acid cycle.
答案: 【generate NADPH and pentoses for the biosynthesis of fatty acids and nucleic acids.

12、 问题:Which compound(s) is/are a high-energy intermediate(s) in glycolysis?
选项:
A:fructose 1,6-bisphosphate
B:NADH
C:1,3-bisphosphoglycerate and phosphoenol pyruvate
D:fructose 1,6-bisphosphate, 1,3-bisphosphoglycerate, and phosphoenol pyruvate
答案: 【1,3-bisphosphoglycerate and phosphoenol pyruvate

13、 问题:Malonate is a competitive inhibitor of succinate dehydrogenase. If malonate is added to a mitochondrial preparation that is oxidizing pyruvate as a substrate, which compound would you expect to decrease in concentration?
选项:
A:citrate
B:fumarate
C:isocitrate
D:pyruvate
答案: 【fumarate

14、 问题:Which compound is NOT an intermediate of the citric acid cycle?
选项:
A:acetyl-CoA
B:citrate
C:oxaloacetate
D:succinyl-CoA
答案: 【acetyl-CoA

15、 问题: In mammals, what process does NOT occur during the citric acid cycle?
选项:
A:formation of α-ketoglutarate
B:generation of NADH and FADH2
C:metabolism of acetyl-CoA to carbon dioxide
D:net synthesis of oxaloacetate from acetyl-CoA
答案: 【net synthesis of oxaloacetate from acetyl-CoA

16、 问题:Conversion of 1 mol of acetyl-CoA to 2 mol of CO2 and CoA via the citric acid cycle results in the net production of:
选项:
A:1 mol of citrate.
B:1 mol of FADH2.
C:1 mol of NADH.
D:1 mol of oxaloacetate.
答案: 【1 mol of FADH2.

17、 问题:Which factor is NOT associated with the oxidation of substrates by the citric acid cycle?
选项:
A:CO2 production
B:FADH2
C:NADH
D:NADPH
答案: 【NADPH

18、 问题:Which enzymatic activity would be decreased by thiamine deficiency?
选项:
A:α-ketoglutarate dehydrogenase complex
B: isocitrate dehydrogenase
C:malate dehydrogenase
D:fumarase
答案: 【α-ketoglutarate dehydrogenase complex

19、 问题:The reaction of the citric acid cycle that produces an ATP equivalent (in the form of GTP) by substrate level phosphorylation is the conversion of:
选项:
A:succinyl-CoA to succinate.
B:citrate to isocitrate.
C:fumarate to malate.
D:succinate to fumarate.
答案: 【succinyl-CoA to succinate.

20、 问题:Which cofactor is required for the conversion of succinate to fumarate in the citric acid cycle?
选项:
A:ATP
B:biotin
C:FAD
D:NAD+
答案: 【FAD

21、 问题:Which process is NOT a metabolic fate for pyruvate in liver tissue?
选项:
A:reduction to lactate
B:oxidative decarboxylation to acetyl-CoA
C: phosphorylation to phosphoenolpyruvate
D:carboxylation to oxaloacetate
答案: 【 phosphorylation to phosphoenolpyruvate

22、 问题:Covalent modification is one way the activity of specific enzymes can be regulated. Which enzyme is NOT regulated in this way?
选项:
A:phosphofructokinase-2
B:pyruvate dehydrogenase
C:phosphorylase kinase
D:All of these enzymes are regulated by covalent modification.
答案: 【All of these enzymes are regulated by covalent modification.

23、 问题:Which statement about mammalian glycogen synthase is NOT correct?
选项:
A:It is especially predominant in liver and muscle.
B:The donor molecule is a sugar nucleotide.
C:The phosphorylated form of this enzyme is active.
D:This enzyme adds the initial glucose unit to a tyrosine residue in glycogenin.
答案: 【The phosphorylated form of this enzyme is active.

24、 问题:Which statement is TRUE of glycogen synthase?
选项:
A:Activation of the enzyme involves a phosphorylation.
B:It catalyzes addition of glucose residues to the nonreducing end of a glycogen chain by formation of (α1 -4) bonds.
C:It uses glucose-6-phosphate as donor of glucose units
D:The enzyme has measurable activity only in liver.
答案: 【It catalyzes addition of glucose residues to the nonreducing end of a glycogen chain by formation of (α1 -4) bonds.

25、 问题:Which statement is TRUE of muscle glycogen phosphorylase?
选项:
A:It catalyzes phosphorolysis of the (α1-6) bonds at the branch points of glycogen.
B:It degrades glycogen to form glucose 6-phosphate.
C:It exists in an active (a) form and an inactive (b) form that is allosterically regulated by AMP.
D:It removes glucose residues from the reducing ends of the glycogen chains.
答案: 【It exists in an active (a) form and an inactive (b) form that is allosterically regulated by AMP.

26、 问题:Which statement is TRUE of glycogen synthesis and breakdown?
选项:
A:Phosphorylation activates the enzyme responsible for breakdown, and inactivates the synthetic enzyme.
B:Synthesis is catalyzed by the same enzyme that catalyzes breakdown.
C:The immediate product of glycogen breakdown is free glucose.
D:Under normal circumstances, glycogen synthesis and glycogen breakdown occur simultaneously and at high rates.
答案: 【Phosphorylation activates the enzyme responsible for breakdown, and inactivates the synthetic enzyme.

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