The given reaction is the sum of the first half reaction reversed and the second half reaction, therefore, the $ \Delta E^{t_0} $ is $ -(-0.320) + 0.82 = 1.14V.
Overall, there is two electron transferred, therefore n = 2. Using the formula $ \Delta G = -nFE $, we get the answer $ 2 \times 96.5 \times 1.14 = -220.02 $
A negative change of free energy means the reaction is spontaneous.
The system preserved 200/220 ~= 90% of energy that is derived from the redox reactions. Compare to a typical car engine which is only 10% - 50% efficient, I'd say the electron transport chain is amazingly efficient.
The exergonic transport of electrons is directly coupled to the endergonic transfer of protons from the mitochondrial matrix to the intermembane space.
The exergonic movement of protons from the intermembane space to the mitochondrial matrix is coupled to the endergonic process of ATP synthesis.
FCCP destroyed the proton gradient and therefore we cannot ATP synthesis is not supported.
The pH 7 solution created the proton gradient and valinomycin, by being able to take potassium [but not chloride] ion out of the mitochondrial matrix, also created a charge gradient, this two things together support ATP synthesis.
We do not have a proton gradient here so it does not support ATP synthesis.
The cyanide block the electron transport chain, but since we have an artificial proton gradient build up, we do not need the electron transport chain, so it still support ATP synthesis.
Oligomycin blocks ATP synthase, so regardless of the artificial proton gradient the setting will not support ATP synthesis.
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