Calculate the free energy change of pumping Ca+2 from the cytosol, where its concentration is about 1.0 x 10-7 M, to the extracellular fluid, where its concentration is about 1.0 mM. Assume a temperature of 37oC and a transmembrane potential of 50 mV (inside more negative) for the plasma membrane.
Calculate the maximum [Glucose]in/[Glucose]out ratio that can be achieved by the plasma membrane Na+-glucose symporter of an epithelial cell when [Na+]in is 12 mM, [Na+]out is 145 mM, the membrane potential is -50 mV (inside negative) and the temperature is 37oC.