4.21 under biochemical standard conditions, aerobic respiration produces approximately 38 molecules of atp per molecule of glucose that is completely oxidized. (a) what is the percentage effi ciency of aerobic respiration under biochemical standard conditions? (b) th e following conditions are more likely to be observed in a living cell: pco2 = 53 mbar, po2 = 132 mbar, [glucose] = 5.6 × 10−2 mol dm−3, [atp] = [adp] = [pi] = 1.0 × 10−4 mol dm−3, ph = 7.4, t = 310 k. assuming that activities can be replaced by the numerical values of molar concentrations, calculate the effi