L1. VG ion channel Flashcards
what are 3 important properties that ion channels have
- recognise ions
- open channel in response
- conduct ions across the membrane
what proteins are ion channels
transmembrane proteins
what are the 2 k+ channels
delayed rectifier K+ and A type k+
how many helices does K + channels have
6
- 4 Voltage sensort and 2 part of pore domain
what is it called when the ion channel structure come together to form a channel
tetramer
how does VGC get inactivated
plugged by its structure until the Em returns back to normal.
then The pore closes after the plugger is removed
similarities between VGC Na and Ca
- channel have single polypeptide
- has 4 domains
- has 6 helicases
how does Na/Ca VGC activated
S4 has + residues so when depol happends, the S4 moves up.
- this causes conformational change in the channel pore.
- the ion influx occurs
- plugged to be inactiavted
an experiment to analyse ion channel fuunction
2 electrode voltage clamp
a channel blocker for KVGC
TTX
a channel blocker
fro NaVGC
TEA
What happens to the current of K when the Vm becomes positive
increases so the efflux of K occur
what is the force driving this current and why
driving force
- membrane potential gets further away from Ek (EQB) so DF increases and more channels open
what is membrane current influenced by
driving force and conductance
what is conductance
no of channels
-direct measure of channel activity
