Biochemistry: Concepts and Connections (2nd Edition)
2nd Edition
ISBN: 9780134641621
Author: Dean R. Appling, Spencer J. Anthony-Cahill, Christopher K. Mathews
Publisher: PEARSON
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Textbook Question
Chapter 3, Problem 18P
Consider the degradation of glucose to pyruvate by the glycolytic pathway:
Glucose + 2ADP + 2Pi + 2NAD+
Calculate
17. For part (b) of this problem, use the following reduction potentials, free energies, and nonequilibrium concentrations of reactants and products:
Consider the last two steps in the alcoholic fermentation of glucose by brewer's yeast:
Pyruvate + NADH + 2H+
a. Do you predict that
b. Calculate the nonequilibrium concentration of ethanol in yeast cells, if
pH = 7.4 and 37o C when the reactants and products are at the concentrations given above.
c. How would a drop in pH affect
d. How would an increase in intracellular CO2 levels affect
e. How would an increase in intracellular CO2 levels affect
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When grown anaerobically on glucose, yeast (S. cerevisiae) converts pyruvate to acetaldehyde, then reduces acetaldehyde to
Pethanol using electrons from NADH.
Write the chemical equation for the reaction that reduces acetaldehyde (CH3CHO) to ethanol (CH3CH2OH).
The table provides the standard reduction potential, E', of the relevant half-reactions.
Half-reaction
Acetaldehyde + 2 H+ + 2e¯ → ethanol
NAD+ + 2H+ + 2e¯ → NADH + H+
E'° (V)
-.197
-.320
Calculate the equilibrium constant, K'eq, at 25.0 °C for the reaction that reduces acetaldehyde to ethanol.
K'e
×10
=
eq
The half-reactions involved in the lactate dehydrogenase (LDH) reaction and their standard reduction potentials are (see attached)). Calculate ΔG at pH 7.0 for the LDH-catalyzed reduction of pyruvate under the following conditions: (a) [lactate]/[pyruvate] = 1 and [NAD+]/[NADH] = 1. (b) [lactate]/[pyruvate] = 160 and [NAD+]/[NADH] = 160. (c) [lactate]/[pyruvate] = 1000 and [NAD+]/[NADH] = 1000. (d) Discuss the eff ect of the concentration ratios in Parts a–c on the direction of the reaction.
Referring to for E′0 values, calculate ΔG°′ for oxidation of malate by malate dehydrogenase.
Chapter 3 Solutions
Biochemistry: Concepts and Connections (2nd Edition)
Ch. 3 - Prob. 1PCh. 3 - Given the following reactions and their...Ch. 3 - The decomposition of crystalline N2O5...Ch. 3 - The oxidation of glucose to CO2 and water is a...Ch. 3 - Prob. 5PCh. 3 - In another key reaction in glycolysis,...Ch. 3 - Assume that some protein molecule, in its folded...Ch. 3 - When a hydrophobic substance like a hydrocarbon is...Ch. 3 - It is observed that as temperature is increased,...Ch. 3 - Suppose a reaction has Ho and So values...
Ch. 3 - Prob. 11PCh. 3 - Prob. 12PCh. 3 - Prob. 13PCh. 3 - Undergoing moderate activity, an average person...Ch. 3 - The major difference between a protein molecule in...Ch. 3 - Prob. 16PCh. 3 - Prob. 17PCh. 3 - Consider the degradation of glucose to pyruvate by...Ch. 3 - a. Consider the malate dehydrogenase reaction,...Ch. 3 - Bovine ribonuclease folds with Ho = -280 kJmol-1...
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