Membranes

Question 1

3 Categories of Gated Ion Channels

Answer 1

Mechano
Voltage
or Chemo-sensitive

Question 2

Structure of Inward-Rectifier K+ Channels

Answer 2

2 TM domains with a P loop. Put four subs together for pore. Gate from TM tails in cyt

Question 3

Structure of Voltage-Dependent K+ Channels

Answer 3

8 TM domains with voltage sensor on S4. Need four again.

Question 4

Voltage-Dependent Na+ Channels

Answer 4

Similar to K+ channel except diff selectivity filter and all four subs combined into one long polypep

Question 5

nAchRs

Answer 5

5 subs but 2 alpha subs bind
Selective for cations
TM domains have kink but rotate out of the way
Have densensitized state to prevent overstimulation

Question 6

Glutamate R Selectivity and Similarity

Answer 6

Cation selective, look like upside down K+ channel

Question 7

3 Things that Control Ion Movement Across Membrane

Answer 7

Concentration gradient
Voltage gradient
Permeability/conductance to particular ion

Question 8

Equation for Conductance of Membrane

Answer 8

of channels x Probability(open) x single channel conductance

Question 9

Net Flux of an Ion Equation

Answer 9

= Permeability of ion x (net driving force on ion, dependent on concentration and voltage gradients)

Question 10

Nernst Equation

Answer 10

Eion = (60mv/Z)log(Co/Ci)

Question 11

KIR Function/Mech

Answer 11

Allow K+ to leave the cell at resting potential, but upon depolarization K+ rushes to leave cell and Mg2+ rushes to block channel, limiting the outward flow of K+