The membrane potential in a particular hyperpolarized cell is measured to be -70 mV. For each of the following channels in this cell, the calculated Nernst equilibrium potential for the corresponding ion is presented. Indicate whether each channel is driven to pass the ion into (I) or out of (O) the cell. Your answer would be a four-letter string composed of letters I and O only, e.g. IIII.
( ) K? channel; the K? equilibrium potential is -60 mV.
( ) Na? channel; the Na? equilibrium potential is +70 mV.
( ) Ca²? channel; the Ca²? equilibrium potential is +130 mV.
( ) Cl- channel; the Cl- equilibrium potential is -90 mV.