Ion Channels I Flashcards
where are ion channels located
on the membrane
what is the function of pore forming membrane proteins
They are pore-forming membrane proteins that establish and control the voltage gradient across the membrane by allowing the flow of ions down their electrochemical gradient
Why are ion channels important
Without channels it is energetically unfavorable to move ions across a membrane
T/F : The regulation of ion channels influences the life of the cell and its functions under normal and pathological conditions
The regulation of ion channels influences the life of the cell and its functions under normal and pathological conditions
Are ion channels pumps
no!! bc they do not require energy
T/F ion channels require ATP
FALSE!! they help ions move down their concentration gradient . Since they do not require ATP, they are not not considered pumps
T/F : Ions move through ion channels passively – down their concentration gradients
True
can ion channels move
no!! they are anchored to the cell membrane , specially the cytoskeleton and extracellular membrane
T/F ion channels are present in almost every cell membrane
true
what is the main difference between gated and non gated ion channels
non gated = non specific
gated - specific
what are the 3 types of gated ion channels
- voltage across the cell membrane
- ligand
- mechanical stimuli - heat and stretch
what is the typical molecular weight of an ion channel
Molecular weights range from 25-250 kD
T/F : Ion channels are integral membrane glycoproteins
true
T/F : Ion Channels usually consist of 2 or more subunits
true
what are the 2 distinct states for ion channels
open - CONDUCTING
closed - NON CONDUCTING
What does it mean for an ion channel to be in an inactivated state
some channels have also inactivated state (open but nonconducting)
- Part of the channel structure or external particle blocks otherwise open channel
What is responsible for the opening and closing of the pore
Conformational changes in channel protein are responsible for opening and closing of the pore
what are the 2 gating theories
Two gating theories –
- Ball and chain
- Paddle
If no confirmational change takes place in ion channel will the ion channel open
no