If the density of K+ channels in the axon was increased by 50%, which of the following statements would be true?﻿

1. The amplitude of the action potential would be reduced by 50%2. The falling phase would be more steep3. The falling phase would have a steeper slope4. The amplitude of the action potential would be increased by 50%5. The relative refractory period would be affected6. The threshold for action potential generation would be more negative (hyperpolarized)7. The nadir (most negative point) of the undershoot phase (after hyperpolarization) would be more negative8. The 'width' of the action action potential would be increased

I said that 2,3 and 7 are correct. 7 is correct because K+ in the cell is high which makes the inside of the cell more positve more K+ would want to go out thus cell becomes more negative. if more K+ are leaving the cell the slope would be steeper. Is this reasoning correct? Also am not sure about the rest can you please explain it to me

Your reasoning is right, the number of channels does control the slope, hence 2 and 3, they both sound the same. 7 isnt right. The concept of more negative or not is an inherent property of the channel and cell. it would not be changed by having more channels.

I'm not sure exactly what number 7 is asking, but the cell membrane potential (with respect to the inside of the cell) would become more negative as read on a microscopic voltmeter. If I understand it as talking about the cell membrane potential then number 7 would be correct.