A cell membrane at 37 C is found to be permeable to Ca2+ but not to anions, and analysis shows the inside Ca2+ concentration to be 0.100 M and the outside concentration to be 0.001 M.

a What potential difference in volts would have to exist across the membrane for Ca2+ to be in equilibrium in the stated concentrations? Assume the activity coefficients are equal to 1. Give the sign of the potential inside with respect to outside.

b If the measured potential inside in +100 mV with respect to the outside, what is the minimum reversible work required to transfer 1 mol of Ca2+ from outside to inside?