Marcus,who works in the laboratory of Dr.Flores,a prominent electrophysiologist,takes readings with a recording electrode placed within a squid axon.He reports to Dr.Flores that the cell is firing an action potential.What measurement did Marcus take with the recording electrode?
A)−70 mV
B)0 mV
C)+40 mV
D)+70 mV

Question

Quizplus · Accepted Answer

A squid axon has a resting membrane potential of around -70mV, which means that it is negatively charged inside compared to the outside. However, when an action potential fires, the charge inside the axon rapidly becomes positive, reaching a peak of around +40mV before returning to its resting potential. Therefore, the measurement Marcus took with the recording electrode when the cell was firing an action potential would be around +40mV, corresponding to the peak of the positive charge inside the axon during the action potential.

Marcus,who Works in the Laboratory of Dr