Gated ion channels
(I)exist because active transporters cannot maintain the gradient at a rate equal to non- gated ion flow.
(II)remain open unless acted on by an external stimulus.
(III)remain open to all ions that are smaller than the pore diameter.
(IV)can transport varying ions.

Question

Quizplus · Accepted Answer

Gated ion channels exist to allow cells to rapidly change their ion permeability in response to various stimuli, not because active transporters cannot maintain the gradient. They do not remain open unless acted on by an external stimulus; rather, they open or close in response to specific stimuli. They are selective for specific ions, not just any ion smaller than the pore diameter.

Gated Ion Channels (I)exist Because Active Transporters Cannot Maintain the Gradient at a Gradient