Structure and Function of Potassium Channels

Question 1

What does K+ channel consist of?

Answer 1

4 protein subunits with a pore in the middle, the K+ specificity is due to the pore’s diameter selective to K+ ions, voltage gated

Question 2

How does Voltage Gating work?

(5)

Answer 2

1. Negative voltage inside cell closes channel
2. Positive voltage inside cell opens channel
3. When channel is open K+ ions can diffuse to the outside
4. The channel rapidly closes again by a globular protein that’s attached to the channel, blocking the pore
5. The channel returns to its original closed state when negative voltage inside the cell is restored