Multiple Choice
Which type of ion channels open in response to changes in membrane potential?
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9. Transport Across Membranes
Ion Channels and Membrane Potential
Multiple Choice
In the context of membrane potential (voltage measured as ), what does a negative cell voltage indicate?
A
The membrane has become freely permeable to all ions, eliminating electrical gradients while maintaining chemical gradients.
B
The outside of the cell is electrically negative relative to the inside.
C
There is no separation of charge across the membrane (the membrane potential is mV).
D
The inside of the cell is electrically negative relative to the outside.
Verified step by step guidance1
Understand that membrane potential (Vm) is defined as the voltage difference across the cell membrane, typically calculated as \(V_{m} = V_{inside} - V_{outside}\).
Recognize that a negative membrane potential means \(V_{inside} < V_{outside}\), indicating the inside of the cell is more negative compared to the outside.
Recall that this negative voltage arises due to the distribution of ions across the membrane and selective permeability, which creates an electrical gradient.
Note that if the membrane were freely permeable to all ions, electrical gradients would dissipate, leading to a membrane potential of 0 mV, which is not the case here.
Therefore, a negative cell voltage specifically indicates that the inside of the cell is electrically negative relative to the outside, reflecting the typical resting membrane potential of many cells.
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