Question

$N{a}^{+}-K^{+}$ pump in axonal membrane

• A. Is operative during depolarisation and transports $3N{a}^{+}$ outwards and $2K^{+}$ into the cell
• B. Is operative during resting stage and transports $3N{a}^{+}$ outwards and $2K^{+}$ into the cell
• C. Is operative during repolarisation and transports $3N{a}^{+}$ outwards and $2K^{+}$ into the cell
• D. Is operative during resting stage and transports $3N{a}^{+}$ into the cell and $2K^{+}$ outwards

Answer 1

The correct option is A Is operative during depolarisation and transports $3N{a}^{+}$ outwards and $2K^{+}$ into the cell

Iconic gradient across the resting membrane are maintained by the active transport of ions by the sodium-potassium pump which transports 3 Na${}^{+}$ outwards for 2 K${}^{+}$ into the cell. By this, the outer surface of the axonal membrane possesses a positive charge while the inner surface becomes negatively charged and therefore, depolarised.

So, the correct answer is 'Is operative during depolarisation and transports 3Na+ outwards and 2K+ into the cell'.