Q. For the maintenance of ionic gradients across the resting membrane, the sodium-potassium pump transports
A) $3Na^{+}$ outwards for $2K^{+}$ into the cell
B) $2Na^{+}$ outwards for $2K^{+}$ into the cell
C) $3Na^{+}$ inwards for $2K^{+}$ out the cell
D) $2Na^{+}$ inwards for $2K^{+}$ out the cell
Explanation
$3Na^{+}$ outwards for $2K^{+}$ into the cell. The plasma membrane of the neuron is polarized due to the high out flow of $Na^{+}$ ions to outside and low intake of $K^{+}$ ion inside. $3Na^{+}$ ions outflow by the ion channel of plasma membrane and $2K^{+}$ ions inflow by it. This creates a difference in the positive potential across the plasma membrane. The membrane is less positive inside which is normally termed as negative inside w.r.t outside
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.