The potassium channel differs from the sodium channel in that only the sodium channel
a. uses energy to force ions from the cell.
b. uses energy to force ions into the cell.
c. does not use energy, whereas the potassium channel does.
d. is typically open, and does not block ion movement.
e. is typically closed, blocking ion movement.
E; Both channels allow ions to leak through them down a concentration gradient, and therefore do not use energy during ion movement (choices a, b, and c). However, the potassium channel is typically open, and potassium ions diffuse to electrochemical equilibrium. The sodium channel, however, is typically closed and only opens when the voltage across the membrane drops.
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