The table shows standard reduction potentials, E., for reactions with n transferred electrons. Oxidant 02 +2H+ FAD Reductant n E. (V) H₂O 2 +0.82 FADH2 2 -0.22 Faraday's constant is 96.48 kJ mol-1 V-1. Electron transfer from NADH or FADH2 to oxygen generates a proton gradient across the mitochondrial membrane. Electrons from NADH result in more protons being pumped across to form the gradient than electrons from FADH2. Calculate the free energy change, AG", for the reduction of O2 with FADH2. Round your answer to the nearest whole number. AG° = kJ mol-1

The table shows standard reduction potentials, E., for reactions with n transferred electrons. Oxidant 02 +2H+ FAD Reductant n E. (V) H₂O 2 +0.82 FADH2 2 -0.22 Faraday's constant is 96.48 kJ mol-1 V-1. Electron transfer from NADH or FADH2 to oxygen generates a proton gradient across the mitochondrial membrane. Electrons from NADH result in more protons being pumped across to form the gradient than electrons from FADH2. Calculate the free energy change, AG", for the reduction of O2 with FADH2. Round your answer to the nearest whole number. AG° = kJ mol-1

Biochemistry

6th Edition

ISBN:9781305577206

Author:Reginald H. Garrett, Charles M. Grisham

Publisher:Reginald H. Garrett, Charles M. Grisham

Chapter27: Metabolic Integration And Organ Specialization

Section: Chapter Questions

Problem 4P

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a) Assuming that ubiquinone is unavailable inside of the cell, calculate the AG and the Keq if electrons are transferred directly from complex I to complex III of the electron transport chain. In your answer include the net equation for this electron transfer. Constants: R= 8.3J/degree'mol, F= 96.1kJ/volt mol, T=298K ( Half Reaction EM ubiquinone + 2e + 2H' Ubiquinol + H2 NAD + 2e+ 2H'→ NADH + H 0.045 -0.320 1/202 + 2e +2H H,O Cytc (Fe") + +le + 1H"→ Cytc (Fe²) 0.816 0.254 b) In a single sentence explain whether or not this electron transfer is possible. /
During electron transfer through the mitochondrial respiratory chain, the overall reaction is NADH + 1/2O2 + H+ arrow forward NAD+ + H2O. The difference in reduction potentials for the two half reactions (delta E) is +1.14 V. Show how you would calculate the standard free energy change, delta G, for the reaction as written. (faraday constant is 96.48 kj/vmol: R=8.314j/mol K=1.987 cal/mol K
The cytochromes are heme-containing proteins that function as electron carriers in the mitochondria. Calculate the difference in the reduction potential (AE°') and the change in the standard free energy (AG°) when the electron flow is from the carrier with the lower reduction potential to the higher. cytochrome c₁ (Fe³+) + e¯ = cytochrome c₁ (Fe2+) E°' = 0.22 V cytochrome c (Fe³+) + e¯ = cytochrome c (Fe²+) E°' = 0.254 V Calculate AE°' and AG°'. AE°' = AG°' = V kJ/mol
Assuming that the pH of the IMS is 1.4 units lower than the pH of the matrix, the free energy yield associated with the transport of a proton from the mitochondrial intermembrane space (IMS) to the mitochondrial matrix is △ G of the reaction is 8.310 KJmol-1 What is the minimum number of protons that must enter the mitochondrial membrane from the IMS in order to synthesize one molecule of ATP?
Under standard conditions, NADH reoxidation by the electron-transport chain has a free-energy change equal to –220 kJ/mol. With 100% efficiency, how many ATP could be synthesized under standard conditions? What is the "actual" efficiency given these numbers?
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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?
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a) Calculate the enzyme and specific activity of a reaction with 3 pM Hsp90 using the following information: The rate is measured in a spectrophotometer as 0.028 OD units/min in a 1 ml reaction volume. The absorbance was detected at 340nm and the extinction coefficient for NADH at this wavelength is 6200L M- 1 min-1 and the molecular mass of Hsp90 is 82.7 kDa. The rate of NADH utilisation is equivalent to the rate of ATP utilised by Hsp90. Show all your calculations and the units for your answers. b) Calculate the turnover number for the reaction described in (a) above
ATP is synthesized from ADP, P, and a proton on the matrix side of the in- ner mitochondrial membrane. We will refer to the matrix side as the "inside" of the inner mitochondrial membrane (IMM). (a) H* transport from the outside of the IMM into the matrix drives this process. The pH inside the matrix is 8.2, and the outside is more acidic by 0.8 pH units. Assuming the IMM membrane potential is 168 mV (inside negative), calculate AG for the transport of 1 mol of H* across the IMM into the matrix at 37 °C: Houtside) Hinside) (b) Assume three mol H* must be translocated to synthesize one mol ATP by coupling of the following reactions: ADP + P, + Hinskde) ATP + H,O(ATP synthesis) 3Hinside)(proton transport) 3Houtside)