### Spontaneity of Reactions Under Standard ConditionsUnder standard conditions, will the following reactions proceed spontaneously as written?#### (1) \[ \text{Fumarate} + \text{NADH} + \text{H}^+ \rightleftharpoons \text{succinate} + \text{NAD}^+ \]#### (2) \[ \text{Cyto a} \left(\text{Fe}^{2+}\right) + \text{cyto b} \left(\text{Fe}^{3+}\right) \rightleftharpoons \text{cyto a} \left(\text{Fe}^{3+}\right) + \text{cyto b} \left(\text{Fe}^{2+}\right) \]### Explanation of Reactions#### Reaction 1:This reaction involves the oxidation of NADH to NAD+ and the reduction of fumarate to succinate. The spontaneity of this reaction under standard conditions depends on the standard reduction potentials (E°) of the involved species. #### Reaction 2: This reaction represents electron transfer between two cytochromes. Specifically, cytochrome a (Fe²⁺) is oxidized to cytochrome a (Fe³⁺), while cytochrome b (Fe³⁺) is reduced to cytochrome b (Fe²⁺). The spontaneity of this reaction under standard conditions also depends on the standard reduction potentials of the cytochromes involved. ### Determining SpontaneityFor both reactions, one would need to compare the standard reduction potentials (E°) of the reactants and products. If the overall cell potential (E° cell) is positive, the reaction is spontaneous under standard conditions, and if it is negative, the reaction is non-spontaneous under standard conditions.

In a biological oxidation-reduction reaction, electrons move from electron donor to electron…

Answered: Under standard conditions, will the…

Biochemistry

9th Edition

ISBN:9781319114671

Author:Lubert Stryer, Jeremy M. Berg, John L. Tymoczko, Gregory J. Gatto Jr.

Publisher:Lubert Stryer, Jeremy M. Berg, John L. Tymoczko, Gregory J. Gatto Jr.

Chapter1: Biochemistry: An Evolving Science

Section: Chapter Questions

Problem 1P

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The Beutler test is used to diagnose GALT (UDP-glucose uridyltransferase) deficiency in infants. Blood from the heel is spotted onto filter paper and the spot is then subjected to an enzyme assay. Galactose 1-phosphate, NADP+ and UDP-glucose are added as substrates to the dried blood. The increase in absorbance at 340nm is measured over time which corresponds to reduction of NADP+ to NADPH . The amount of GALT activity in the blood of patients is therefore measured by stoichiometric relationship to the amount of NADPH produced from NADP+. However, GALT does not directly reduce NADP+ as you can see in the above diagram. Instead, the glucose 1-phosphate product from this reaction is shuttled into the oxidative phase of the pentose phosphate pathway by enzymes also present in RBCs. Which three (or possibly more if you must) enzymes downstream of GALT allow for quantitative correlation of a product of GALT with the appearance of NADPH? What is the stoichiometric relationship…
Refer to the figure shown here, and determine the value of E for the overall oxidation/reduction reaction (refer to the book/lecture slides if you need help with the overall reaction). 121/202 + 2H+ + 2e → H₂0 NAD + H* + 2e → NADH O-1.136 volts O 0.496 volts O+1.136 volts voltsm -0.496 volts EU (volts) +0.816 - 0.320
Refer to Table to explain why FAD rather than NAD+ is used in the succinate dehydrogenase reaction.
Interested in studying ethanol fermentation, you prepare two solutions of yeast extract that contains the cytosolic contents of Saccharomyces cerevisiae. You add glucose to both extracts at time zero, but to one (in red) you also add inorganic phosphate (added in two batches). Using a gas sensor, you monitor the CO2 generated by the two solutions over time and obtain the following data:
When pure reduced cytochrome c is added to carefully prepared mitochondria along with ADP, Pi, antimycin A, and oxygen, the cytochrome c becomes oxidized, and ATP is formed, with a P/O ratio approaching 1.0.(a) Indicate the probable flow of electrons in this system.(b) Why was antimycin A added?(c) What does this experiment tell you about the location of coupling sitesfor oxidative phosphorylation?(d) Write a balanced equation for the overall reaction (including cyt c oxidation and ATP synthesis).(e) Calculate ΔG°′ for the above reaction, using E′0 values from Table 14.1and a ΔG°′ value for ATP hydrolysis of -32.2 kJ/mol.
To carefully prepared mitochondria were added succinate, oxidized cytochrome c, ADP, orthophosphate, and sodium cyanide. The overall balanced equation is: succinate + 2 cyt c(ox) + ADP + Pi --> fumarate + 2 cyt c(red) + ATP + H2O The standard state free energy of this system is O -10.3 kJ/mol 42.5 kJ/mol O 10.3 kJ/mol -42.5 kJ/mol
The following two reactions are coupled in the last step of glycolysis (catalyzed by the enzyme pyruvate kinase). РЕР + Н.О € Руr + Pi ADP + Pi → ATP + H2O AG° = -14.8 kcal/mol AG° = +7.3 kcal/mol D) The steady-state concentrations of ATP, ADP, and pyruvate in human erythrocytes are 2.24 mM, 0.25 mM, and 0.051 mM, respectively. What would be the concentration of PEP in these cells if the coupled reaction was at equilibrium?
Answer a to d for amine reaction
Write out the full redox reaction that happens when both of these reactions are added to the same reaction where there is 1M concentrations of each reactant and products, pH7, and temeprature is 290K. Identify which compounds will be reduced and which compounds will be oxidized. redox reaction 1: Pyruvate¯ + 2H+ + 2e¯ → lactate¯ E'o(V) = -0.185 redox reaction 2: NAD+ + H+ + 2e¯ → NADH E'o(V) = -0.320
7) The following questions apply to glycolysis (figure 3-41 on page 79 of the 12th edition), the Krebs cycle (figure 3-44 on page 82) and to oxidative phosphorylation (figure 3-45 on page 84). Calculate the total amount of ATP produced from one glucose molecule if: a. The oxidation of NADH + H* to NAD* + 2H* produced 4 ATP. b. The oxidation of FADH₂ to FAD + 2H* produced 1 ATP. c. Each step of the Krebs cycle that produces NADH+H* produced FADH2 instead. d. Each step of the Krebs cycle that produces FADH2 produced NADH + H+ instead. e. Sucrose is substituted for glucose.
a newly identified bacterium called Nomore biochem is unable to synthesize ubiquinone. A mobile electron carrier called CXC3 is used as a substitute. From the information provided in the table, calculate delta G' and Keq value at 298K for the redox reaction that occurs in the Nomore Biochem electron transport chain. (constants: R=8.3 J/degree x mol, F= 96.1 kJ/v x mol Half Reactions E' (V) ubiquinone + 2e- + 2H+--> Ubiquinol + H2 0.045 NAD+ + 2e- + 2H+ --> NADH + H+ -0.320 CXC3 + 2e- + 2H+ --> CXC3H2 -0.450 explain the impact that using CXC3 instead of ubiquinone will have on ATP production in the cell. How might the cell adapt to this situation?
All dehydrogenases of glycolysis and the TCA cycle use NAD* (E° for NAD*/NADH is -0.32V) as electron acceptor except succinate dehydrogenase (which uses FAD (E° for FAD/FADH2 is 0.05V). Based on AG° = -NFEº, show and state (1-2 sentences) why is FAD a more appropriate electron acceptor than NAD* in the dehydrogenation of succinate (consider the E° values of %3D Uptake in Na+ Vmax Uptake in absence of Na+ Vmax substrate K: (mM) Kt (mM) L-leucine 420 0.24 23 0.2 D-Leucine 310 4.7 5 4.7 L-valine 225 0.31 19 0.31 fumarate/succinate (E° = 0.031), NAD*/NADH, and the succinate dehydrogenase FAD/FADH2).

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Under standard conditions, will the following reactions proceed spontaneously as written? (1) Fumarate + NADH + H+ (2) succinate + NAD+ Cyto a (Fe²+) + cyto b (Fe³+) = cyto a (Fe³+) + cyto b (Fe²+)