The potential difference across a cell membrane from outside to inside is initially at − 90 mV (when in its resting phase). When a stimulus is applied, Na + ions are allowed to move into the cell such that the potential changes to + 20 mV for a short amount of time.
(a) If the membrane capacitance per unit area is 1μF/cm2, how much charge moves through a membrane of area 0.05 cm2?
(b) The charge on Na + is + e.
How many ions move through the membrane?