Becker's World of the Cell (9th Edition)
9th Edition
ISBN: 9780321934925
Author: Jeff Hardin, Gregory Paul Bertoni
Publisher: PEARSON
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Chapter 9, Problem 9.8PS
QUANTITATIVE Glycolysis and Gluconeogenesis. As Figure 9-12 indicates, gluconeogenesis is accomplished by what is essentially the reverse of the glycolytic pathway but with bypass reactions in place of the first, third, and tenth reactions in glycolysis.
- (a) Explain why it is not possible to accomplish gluconeogenesis by a simple reversal of all the reactions in glycolysis.
- (b) Write an overall reaction for gluconeogenesis that is comparable to Reaction 9-16 for glycolysis.
- (c) Explain why gluconeogenesis requires the input of six molecules of nucleoside triphosphates (four ATPs and two GTPs) per molecule of glucose synthesized, whereas glycolysis yields only two molecules of ATP per molecule of glucose.
- (d) Assuming concentrations of ATP, ADP, and Pi are such that ΔG′ for the hydrolysis of ATP is about −10 kcal/mol, what is the approximate ΔG′ value for the overall reaction for gluconeogenesis that you wrote in part b?
- (e) With all of the enzymes for glycolysis and gluconeogenesis present in a liver cell, how does the cell “know” whether it should be synthesizing or catabolizing glucose at any given time?
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Chapter 9 Solutions
Becker's World of the Cell (9th Edition)
Ch. 9 - How are catabolic and anabolic pathways similar?...Ch. 9 - Prob. 9.2CCCh. 9 - Why do oxidation and reduction reactions always...Ch. 9 - How can glucose be oxidized in the absence of...Ch. 9 - In the absence of oxygen, why is it necessary to...Ch. 9 - Prob. 9.6CCCh. 9 - Prob. 1QCh. 9 - Why dont glycolysis (glucose to pyruvate) and...Ch. 9 - Why are the key regulatory enzymes in glycolysis...Ch. 9 - Why do cancer cells carry out high rates of...
Ch. 9 - High-Energy Bonds. When first introduced by Fritz...Ch. 9 - The History of Glycolysis. Following are several...Ch. 9 - Glycolysis in 25 Words or Fewer. Complete each of...Ch. 9 - Energetics of Carbohydrate Utilization. The...Ch. 9 - QUANTITATIVE Glucose Phosphorylation. The direct...Ch. 9 - Ethanol Intoxication and Methanol Toxicity. The...Ch. 9 - Propionate Fermentation. Although lactate and...Ch. 9 - QUANTITATIVE Glycolysis and Gluconeogenesis. As...Ch. 9 - Prob. 9.9PSCh. 9 - Youve Got Some Explaining to Do. Explain each of...Ch. 9 - Arsenate Poisoning. Arsenate (HAsO42) is a potent...Ch. 9 - Life Without Phosphofructokinase. Many bacteria do...Ch. 9 - Prob. 9.13PS
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- Of the steps illustrated how many are unidirectional? Identify the substrate and product of each of these steps. Identify the three enzymes that are likely to be regulated in glycolysis? How did you make this determination. Glycogen synthase is an enzyme that catalyzes the synthesis of glycogen from glucose. Glucose 6 phosphate activates glycogen synthase by allosteric regulation. Illustrate and describe how this allosteric modulation is likely to occur? Glycogen phosphorylase, an enzyme that catalyzes the breakdown of glycogen to form glucose, is active when a phosphate group is added. This is an example of enzyme regulation by ____________________________.arrow_forwardMetabolic regulation (Ch. 15) 1. The Vmax of the enzyme glycogen phosphorylase from skeletal muscle is much greater than the Vmax of the same enzyme from liver tissue. (a) What is the physiological function of glycogen phosphorylase in skeletal muscle? In liver tissue? (b) Why does the Vmax of the muscle enzyme need to be larger than that of the liver enzyme?arrow_forwardBioenergetics: Answer the following questions regarding bioenergetics/ oxidative phosphorylation: Given the following reactions and AGs for each reaction, answer the two questions that follow; be sure to give complete answer including proper units and sign(s) wherever necessary: Reaction #1 (AG = -2.3 kcal/mol): A+ B2 C+D Reaction #2 (AG = +5.3 kcal/mol): C+ K 2R Reaction #3 (AG = -4.5 kcal/mol): R 2 Y+Z 7. Calculate AG for overall reaction: AR>Z Free Energy Change Reactions #1-3 = 8. Which direction is this overall process (#1-3) predicted to go (circle one)? forward OR backwardarrow_forward
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