Assume a pH gradient of 4.0 units across a thylakoid membrane, with the lumen more acidic than the stroma.
(a) What is the standard free energy change per mol of protons associated with this gradient at 25o C?
(b) What is the longest wavelength of light that could provide enough energy per photon to pump one proton against this gradient, assuming a 20% efficiency in photosynthesis and T = 25o C?
(c) What is the standard free energy change per mol O2 produced? How does this compare to the energy required to drive the synthesis of ATP?