Help now! Fast and clear responses please 7. Which of these coenzymes participat
ID: 186266 • Letter: H
Question
Help now! Fast and clear responses please7. Which of these coenzymes participates directly in the oxidation-reduction reactions thae convert glucose to lactate? A) ADP/ATP B) NAD+NADH C) UDP-glucose D) TPPITPP+ E) FAD/FADH 8. In glycolysis, fructose l 6 bisphosphate is converted to two products with a standard free-energy change (AG*) of 23.8 kJ/mol. Under what conditions (encountered in a metabolically active cellD will the free-energy change (AG) be negative, enabling the reaction to proceed? A) Under standard state conditions. B) When the concentrations of the two products are exactly the same. C) By the removal of products such that the concentration of reactants is large relative to products. D) The reaction will not go forward spontaneously under any conditions because the AG is positive. E) When there is a high concentration of products relative to the concentration of fructose 1,6-bisphosphate. 9. Galactosemia is a disease in humans associated with a defect in: A) hexokinase B) UDP-galactose C) Intestinal absorption of sucrose D) Intestinal absorption of galactose E) UDP-glucose-4-epimerase 10. Which of the following statements is incorrect? A) In anaerobic muscle, pyruvate is converted to lactate. B) In anaerobic conditions pyruvate does not form because glycolysis slows. C) Reduction of pyruvate to lactate regenerates a coenzyme essential for glycolysis. D) In acrobic conditions pyruvate is eventually metabolized in the citric acid cycle. B) In micro-organisms (microbes) growing anaerobically, pyruvate is converted to ethanol. 11. Which enzyme(s) in glycolysis is (are) a regulatory enzyme that responds) to rising cellular levels of glucose-6- phosphate? B) pyruvate kinase C) phosphofructokinase-1 D) All of these E) Only B and C 12. A metabolic function of the pentose phosphate pathway is to: A) oxidize phosphate. B) generate NADPH and ribose-5-phosphate. C) participate in oxidation-reduction reactions during the formation of H O. D) provide intermediates for the citric acid cycle. E) synthesize phosphorus pentoxide. 13. In general, regulatory enzymes of metabolic pathways: A) have a large negative G for the reaction they catalyze. B) are allosteric enzymes. C) respond to effector molecules that are intermediates in metabolism. D) All of these apply to regulatory enzymes E) A and B only are correct.
Explanation / Answer
7. Answer is option B. When sufficient oxygen is not present in the muscle cells for further oxidation of pyruvate and NADH produced in glycolysis, NAD+ is regenerated from NADH by reduction of pyruvate to lactate.Pyruvate is converted to lactate by the enzyme lactate dehydrogenase.
8. Here answer will be option E. According to the situation given in question, the Gibbs free energy for the reaction will be negative. Whenever there is negative value of Gibbs Free Energy, then reaction becomes spontaneous.
9. Galactosemia (British galactosaemia) is a rare genetic metabolic disorder that affects an individual's ability to metabolize the sugar galactose properly. Galactosemia follows an autosomal recessive mode of inheritance that confers a deficiency in an enzyme responsible for adequate galactose degradation. Hence answer will be option D.
10. When sufficient oxygen is not present in the muscle cells for further oxidation of pyruvate and NADH produced in glycolysis, NAD+ is regenerated from NADH by reduction ofpyruvate to lactate. Pyruvate is converted to lactate by the enzyme lactate dehydrogenase.. Hence answer will be option B.
11. Within a cell, glucose 6-phosphate is produced by phosphorylation of glucose on the sixth carbon. This is catalyzed by the enzyme hexokinase in most cells, and, in higher animals, glucokinase in certain cells, most notably liver cells. Hence answer is option A.
12. The primary results of the pathway are: The generation of reducing equivalents, in the form of NADPH, used in reductive biosynthesis reactions within cells (e.g. fatty acid synthesis). Production of ribose 5-phosphate (R5P), used in the synthesis of nucleotides and nucleic acids. Hence answer will be Option B.
13. Answer is option D.
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