BMS03-1015 Action Potential

Question 1

What determines the opening on channels?

Answer 1

Voltage

Question 2

How many sub units make a potassium channel?

Answer 2

4

Question 3

What does the membrane become permeable to first in an action potential?

Answer 3

Na

Question 4

Which channel is fast, Na or K?

Answer 4

Na

Question 5

Which has a higher conductance, Na or K?

Answer 5

Na

Question 6

Conductance

Answer 6

The degree something conducts electricity

Question 7

What does the action potential depend on?

Answer 7

Na

Question 8

Why is there a threshold?

Answer 8

At rest K out is much greater than Na in

Question 9

Charge Q (coulombs)=

Answer 9

Capacitance x voltage

Question 10

Charge Q value

Answer 10

10 to the power of -7

Question 11

How many coulombs of charge does a mole of monovalent ion have?

Answer 11

10 to the power of 5

Question 12

How to work out how many moles are required for charge separation?

Answer 12

10 -7 / 10 5 = 10 -12

Question 13

How is the AP propagated?

Answer 13

Along axoplasm and across membrane (in a circle)

Question 14

Describe the circles

Answer 14

2 next to eachother in opposite directions opening Na and opening K

Question 15

How does myelin increase conductance? (3)

Answer 15

Stronger current forced through axoplasm to the next node
Decrease the ability for membrane to store charge
Thicker axons so there is lower resistance in the membrane

Question 16

Why are unmyelinated axon slower? (2)

Answer 16

Lower amount of current forced through axoplasm so its dissipates and voltage falls faster
More charge stored at the membrane so voltage changes more slowly