Quiz
Ch. 14
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Fragen in diesem Quiz (23)
1Glycolysis is the name given to a metabolic pathway occurring in many different cell types. It consists of 11 enzymatic steps that convert glucose to lactic acid. Glycolysis is an example of:
- Aaerobic metabolism.
- Banabolic metabolism.
- Ca net reductive process.
- Dfermentation.
- Eoxidative phosphorylation
2The anaerobic conversion of 1 mol of glucose to 2 mol of lactate by fermentation is accompanied by a net gain of:
- A1 mol of ATP.
- B1 mol of NADH.
- C2 mol of ATP.
- D2 mol of NADH.
- Enone of the above.
- A1 mol of ATP.
3During 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:
- AA) dihydroxyacetone phosphate → glycerol 3-phosphate
B) glucose 6-phosphate → fructose 6-phosphate
C) isocitrate → α-ketoglutarate
D) oxaloacetate → malate
E) pyruvate → lactate - Bdihydroxyacetone phosphate → glycerol 3-phosphate
- Cglucose 6-phosphate → fructose 6-phosphate
- Disocitrate → α-ketoglutarate
- Eoxaloacetate → malate
- Fpyruvate → lactate
- AA) dihydroxyacetone phosphate → glycerol 3-phosphate
4If glucose labeled with 14C in C-1 were fed to yeast carrying out the ethanol fermentation, where would the 14C label be in the products?
- AIn C-1 of ethanol and CO2
- BIn C-1 of ethanol only
- CIn C-2 (methyl group) of ethanol only
- DIn C-2 of ethanol and CO2
- EIn CO2 only
- AIn C-1 of ethanol and CO2
5The conversion of 1 mol of fructose 1,6-bisphosphate to 2 mol of pyruvate by the glycolytic pathway results in a net formation of:
- A1 mol of NAD+ and 2 mol of ATP.
- B1 mol of NADH and 1 mol of ATP.
- C2 mol of NAD+ and 4 mol of ATP.
- D2 mol of NADH and 2 mol of ATP.
- E2 mol of NADH and 4 mol of ATP.
- A1 mol of NAD+ and 2 mol of ATP.
6In an anaerobic muscle preparation, lactate formed from glucose labeled in C-3 and C-4 would be labeled in:
- Aall three carbon atoms.
- Bonly the carbon atom carrying the OH.
- Conly the carboxyl carbon atom.
- Donly the methyl carbon atom.
- Ethe methyl and carboxyl carbon atoms.
- Aall three carbon atoms.
7Which of the following statements is not true concerning glycolysis in anaerobic muscle?
- AFructose 1,6-bisphosphatase is one of the enzymes of the pathway.
- BIt is an endergonic process.
- CIt results in net synthesis of ATP.
- DIt results in synthesis of NADH.
- EIts rate is slowed by a high [ATP]/[ADP] ratio.
- AFructose 1,6-bisphosphatase is one of the enzymes of the pathway.
8When a muscle is stimulated to contract aerobically, less lactic acid is formed than when it contracts anaerobically because:
- Aglycolysis does not occur to significant extent under aerobic conditions.
- Bmuscle is metabolically less active under aerobic than anaerobic conditions.
- Cthe lactic acid generated is rapidly incorporated into lipids under aerobic conditions.
- Dunder aerobic conditions in muscle, the major energy-yielding pathway is the pentose phosphate pathway, which does not produce lactate.
- Eunder aerobic conditions most of the pyruvate generated as a result of glycolysis is oxidized by the citric acid cycle rather than reduced to lactate.
- Aglycolysis does not occur to significant extent under aerobic conditions.
9Glycolysis in the erythrocyte produces pyruvate that is further metabolized to:
- ACO2.
- Bethanol.
- Cglucose.
- Dhemoglobin.
- Elactate.
- ACO2.
10When a mixture of glucose 6-phosphate and fructose 6-phosphate is incubated with the enzyme phosphohexose isomerase, the final mixture contains twice as much glucose 6-phosphate as fructose 6-phosphate. Which one of the following statements is most nearly correct, when applied to the reaction below (R = 8.315 J/mol·K and T = 298 K)?
Glucose 6-phosphate ↔ fructose 6-phosphate- AΔG'° is +1.7 kJ/mol.
- BΔG'° is –1.7 kJ/mol.
- CΔG'° is incalculably large and negative.
- DΔG'° is incalculably large and positive.
- EΔG'° is zero.
- AΔG'° is +1.7 kJ/mol.
11In glycolysis, fructose 1,6-bisphosphate is converted to two products with a standard free-energy change (ΔG'°) of 23.8 kJ/mol. Under what conditions (encountered in a normal cell) will the free-energy change (ΔG) be negative, enabling the reaction to proceed to the right?
- AIf the concentrations of the two products are high relative to that of fructose 1,6-bisphosphate.
- BThe reaction will not go to the right spontaneously under any conditions because the ΔG'° is positive.
- CUnder standard conditions, enough energy is released to drive the reaction to the right.
- DWhen there is a high concentration of fructose 1,6-bisphosphate relative to the concentration of products.
- EWhen there is a high concentration of products relative to the concentration of fructose 1,6-bisphosphate.
- AIf the concentrations of the two products are high relative to that of fructose 1,6-bisphosphate.
12Glucose labeled with 14C in C-1 and C-6 gives rise in glycolysis to pyruvate labeled in:
- AA and C.
- Ball three carbons.
- Cits carbonyl carbon.
- Dits carboxyl carbon.
- Eits methyl carbon.
- AA and C.
13If glucose labeled with 14C at C-1 (the aldehyde carbon) were metabolized in the liver, the first radioactive pyruvate formed would be labeled in:
- Aall three carbons.
- Bboth A and C.
- Cits carbonyl carbon.
- Dits carboxyl carbon.
- Eits methyl carbon.
- Aall three carbons.
14In an anaerobic muscle preparation, lactate formed from glucose labeled in C-2 would be labeled in:
- Aall three carbon atoms.
- Bonly the carbon atom carrying the OH.
- Conly the carboxyl carbon atom.
- Donly the methyl carbon atom.
- Ethe methyl and carboxyl carbon atoms.
- Aall three carbon atoms.
15If glucose labeled with 14C in C-3 is metabolized to lactate via fermentation, the lactate will contain 14C in:
- Aall three carbon atoms.
- Bonly the carbon atom carrying the OH.
- Conly the carboxyl carbon atom.
- Donly the methyl carbon atom.
- Ethe methyl and carboxyl carbon atoms.
- Aall three carbon atoms.
16Which of these cofactors participates directly in most of the oxidation-reduction reactions in the fermentation of glucose to lactate?
- AADP
- BATP
- CFAD/FADH2
- DGlyceraldehyde 3-phosphate
- ENAD+/NADH
- AADP
17In comparison with the resting state, actively contracting human muscle tissue has a:
- Ahigher concentration of ATP.
- Bhigher rate of lactate formation.
- Clower consumption of glucose.
- Dlower rate of consumption of oxygen
- Elower ratio of NADH to NAD+.
- Ahigher concentration of ATP.
18The steps of glycolysis between glyceraldehyde 3-phosphate and 3-phosphoglycerate involve all of the following except:
- AATP synthesis.
- Bcatalysis by phosphoglycerate kinase.
- Coxidation of NADH to NAD+.
- Dthe formation of 1,3-bisphosphoglycerate.
- Eutilization of Pi.
- AATP synthesis.
19The first reaction in glycolysis that results in the formation of an energy-rich compound (i.e., a compound whose hydrolysis has a highly negative ΔG'°) is catalyzed by:
- Aglyceraldehyde 3-phosphate dehydrogenase.
- Bhexokinase.
- Cphosphofructokinase-1.
- Dphosphoglycerate kinase.
- Etriose phosphate isomerase.
- Aglyceraldehyde 3-phosphate dehydrogenase.
20Which of the following is a cofactor in the reaction catalyzed by glyceraldehyde 3-phosphate dehydrogenase?
- AATP
- BCu2+
- Cheme
- DNAD+
- ENADP+
21In the phosphoglycerate mutase reaction, the side chain of which amino acid in the enzyme is transiently phosphorylated as part of the reaction?
- Aserine
- Bthreonine
- Ctyrosine
- Dhistidine
- Earginine
- Aserine
22Inorganic fluoride inhibits enolase. In an anaerobic system that is metabolizing glucose as a substrate, which of the following compounds would you expect to increase in concentration following the addition of fluoride?
- A2-phosphoglycerate
- BGlucose
- CGlyoxylate
- DPhosphoenolpyruvate
- EPyruvate
- A2-phosphoglycerate
23Glycogen is converted to monosaccharide units by:
- Aglucokinase.
- Bglucose-6-phosphatase
- Cglycogen phosphorylase.
- Dglycogen synthase.
- Eglycogenase.
- Aglucokinase.
Informationen
- Beschreibung
- Quiz am Ch. 14, erstellt von super_birdie am 21/08/2014.
- Autor
- super_birdie
- Sprache
- English
- Aufrufe
- 245
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