Because electron transport is coupled to ADP phosphorylation, it is theoretically possible to drive electrons backwards up the chain, against the potential gradient, at the expense of ATP. Consider a bacterium at 25°C that can transfer electrons from succinate to NAD+ by means of a reverse of electron transport: succinate + NAD+ ---? fumarate + NADH. If the intracellular concentration of Pi is 0.01 M, calculate the [ATP]/[ADP] ratio that would be required to maintain the steady state ratio of [NADH]/[succinate] at 0.01. Assume that the concentrations of fumarate and NAD+ are equal.