During the propagation of an action potential, what would be the effect of a mutation in...
During the propagation of an action potential, what would be the effect of a mutation in the voltage-gated Na+-channels that does not allow “inactivation” phase to occur, such that these channels go directly from open to closed conformations?
a) The neuron with the mutant Na+ channels will start letting in calcium ions and generate a calcium-based action potential that is stronger than the sodium-based action potential.
b) The neuron with the mutant Na+ channel will exhibit a reverse electrochemical gradient of both Na+ and K+ (such that [K+] will be greater outside the cell than inside)
c) In a neuron with the mutant Na+-channel, an action potential may generate a “backwards” wave in which the action potential generate new action potentials in the opposite direction.
d) The neuron with the mutant Na+-channel (starting completely at rest, correctly polarized) will not be able to transmit an action potential down the length of its axon, not even once.
e) There will be no significant effect of this mutation.
Homework Answers
Answer: D --- the neuron with the mutant Na+ channel ( starting completely at rest, correctly polarized) will not be able to transmit an action potential down the length of it's axon, not even once.
--- depolarization is occured because of Na+ Voltage gated ion channels which are very fast to open to reverse the membrane potential to +30mV. they are also very fast to close ,becomes inactive at +30mV and causes initial repolarization.
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