L1

Question 1

How can ion channels be grouped?

Answer 1

• function
• type of ion
• properties (voltage/ligand gated)
• regulation (atp, ca2+ (gating)
• molecular structure

Question 2

how many TMDs does a voltage gated potassium channel have?

Answer 2

6TMDs and a pore region

4 some units come together to make a functional channel

Question 3

which TMD is the voltage sensor?

Answer 3

TMD4

Question 4

Why are mutations which effect Kv dominant?

Answer 4

because all 4 ion channels needed to come together to make a functional channel, if only one gene is mutated the ion channel cannot form as not all 4 subunits are functional

Question 5

how many TMDs does Kir have?

Answer 5

2TMDs and a pore region. (need 2 subunits to come together)

Question 6

how many TMDs does Nav have?

Answer 6

24TMD and 4 pore regions

(4 blocks of 6)-all one unit

Question 7

how many TMDs does Cav have?

Answer 7

24TMDs, 4 pore regions

Question 8

what is the driving force for ion movement?

Answer 8

(Vm-Ei)

membrane potential- nernst potential

Question 9

what nernst is resting potential close to?

Answer 9

resting potential of normal physiological cell is close to nernst potential value for potassium. (as high permeability / conc of potassium in resting cell)

Question 10

What is a potassium channel blocker?

Answer 10

TEA
- moves potential away from nernst for potassium (becomes more positive)/ less negative)

Ba2+

Question 11

when does Vrev = Ei (nernst)?

Answer 11

where there is no net current flow through the channels

I=0

Question 12

when will Ek = Ei?

Answer 12

only the same is channel is 100% exclusively selective to potassium. (rare as channel is never 100% specific)

Question 13

what are inward and outward currents?

Answer 13

outward = positive ion out/negative ion in  (positive (+Ve))
inward = positive ion in / negative ion out(negative -Ve)

Question 14

what are blockers of the Nav channel?

Answer 14

tetrodotoxin (TTX)

ProTx-11

Question 15

Give Kir channel blocker

Answer 15

Ba2+

quinidine

Question 16

give blocker for CLC

Answer 16

DIDs

Question 17

what effects do blockers have on current?

Answer 17

• moves the current closer to 0 (current decreases)

likely to be further away from nernst

Question 18

what is Ohms law?

Answer 18

V=IR

also R=V/I
G=I/V
G=conductance

Question 19

what is Vrev?

Answer 19

reverse potential

V when current =0 (Vrec can substitute Ei)

Question 20

give equation for current

Answer 20

I= N. Po. g. (Vm-Ei)