Question

question 56 (1.7 points)
the depolarization phase of an action potential is punctuated by the closing of inactivation gates in the voltage gated sodium ion channels. all of the following are consequences of this inactivation except one. choose the statement below that is not a consequence of the closing of inactivating gates.
a) this allows for the one way transmission of action potential down the axon.
b) this stops the depolarization of the axon membrane.
c) this limits the frequency of action potentials down the axon.
d) this allows for the efflux (diffusion out) of potassium ions, resulting in the repolarization of the cell.

Explanation:

• Option A: When inactivation gates close, sodium influx stops in that region. Since the previous region is refractory (due to inactivation), action potential moves forward (one - way).
• Option B: Closing of inactivation gates stops sodium entry, which is a key part of depolarization.
• Option C: The inactivation period (due to closing of inactivation gates) limits how often action potentials can fire (frequency).
• Option D: Repolarization is mainly due to potassium efflux through voltage - gated potassium channels (not directly because of the closing of sodium inactivation gates). The closing of sodium inactivation gates stops depolarization, but potassium channels are responsible for the main event of repolarization.

Answer:

D. This allows for the efflux (diffusion out) of potassium ions, resulting in the repolarization of the cell.