Site MapHelpFeedbackVoltage-Gated Channels and the Action Potential (Quiz 2)
Voltage-Gated Channels and the Action Potential (Quiz 2)

How is charge generated across a membrane? Gradients across a membrane can be both chemical and electrical. There is a separate chemical gradient for each molecule and ion. The electrical gradient is the sum total of the charge differences caused by the concentration gradients of the various ions. When a neuron is at rest electrical and chemical gradients are maintained by differences in the ability of different ions to cross the membrane. If one ion is free to move across the membrane and another is not then the one that is free to move will tend to move towards equilibrium, with equal concentrations on both sides. As the other ion is not free to move this may lead to the build up of an electrical gradient. Eventually the two forces acting on the system will balance out leading to electrical and chemical gradients that counteract one another.

View the animation below, then complete the quiz to test your knowledge of the concept.






1At resting membrane potential, which of the following statements about the voltage-gated sodium ion (Na+) channels is TRUE?
A)activation gates are closed and inactivation gates are open
B)activation gates are open and inactivation gates are closed
C)activation and inactivation gates are open
D)activation and inactivation gates are closed
E)activation and inactivation gates alternate between open and closed



2During depolarization, which of the following statements about voltage-gated ion channels is TRUE?
A)K+ gates open before Na+ gates
B)Na+ gates open before K+ gates
C)Na+ and K+ gates open at the same time
D)Na+ gates open while K+ gates remain closed
E)K+ gates open while Na+ gates remain closed



3Depolarization occurs because
A)more K+ diffuse into the cell than Na+ diffuse out of it.
B)more K+ diffuse out of the cell than Na+ diffuse into it.
C)more Na+ diffuse into the cell than K+ diffuse out of it.
D)more Na+ diffuse out of the cell than K+ diffuse into it.
E)both Na+ and K+ diffuse into the cell.



4The sodium-potassium pump is involved in establishing the resting membrane potential.
A)True
B)False



5The voltage-gated potassium channels close before the membrane potential is brought back to its resting level.
A)True
B)False







Animation Quiz SiteOnline Learning Center

Home > Biology 1 > Chapter 48 > Voltage-Gated Channels and the Action Potential (Quiz 2)