At the celluar membrane of some bacteria, redox reactions in the membrane generate pH gradient of deltapH=1.0 (interieor higher by one unit) and a membrane potential of -120mv(interior negative). This "proton-motive" force can be used to synthesize ATP from ADP and phosphate inside the cell. Temperature is 37 degrees Celsius, [ADP]= 1mM, [phosphate]= 2mM, for ATP hydrolysis delta G naught= -30.5 kJ/mole
1. How much free energy is made available by the pH gradient and membrane potential for the transport of proteins into the cell?
2. As protons transported into cell, ATP synthesis can be coupled to this process by ATP synthase. At 100% efficiency, under conditions above, how many proteins must be transported to synthesize one molecule of ATP?