Question

2. A) List and briefly discuss the different types of movement of Na+ across the plasma membrane of a neuron (or a typical cell). B) EXPLAIN why inhibiting the sodium/potassium transport pump in neurons will not have an immediate effect on the membrane potential. C) Over time the membrane will depolarize if the “pump” is blocked – explain how this ATPase creates an “electrogenic” effect.

Answer 1

A). The channels has three states.

Closed to open: Depolarization is the major step, more Na+ influx depolarizes the membrane which opens more channels and inturn depolarizes the membrane more.

Open to inactive:Depolarization is the main step to inactivate channel, once the channel is open it will switches to inactive state and cannot be opened.

Inactive to closed: The channel will not switch back to the closed state until the membrane has repolarized.

B). because pumps maintain the potential gradient and restore them once the cell has fired.

C). Na⁺/K⁺ATPase creates net flow of charge.