Lecture 2 (Bioelectricity & ion channels) Flashcards
Why is it important for cell to be impermeable to anions?
Proteins are not membrane permeable so change of potential inside cell, if anions can move across membrane would change potential
Describe movement in Na+/K+ ATPase?
3Na+ moves out 2K+moves in
(loss positive charge)
Describe the K+ potential across cell?
High intracellular K+, low extracellular K+
Describe the potential gradients effect of K+ movement?
K+ moves in due to potential gradient
Describe the overall K+ movement?
Conc gradient moving K+ out
Potential gradient moving K+ in
So, no net movement of K+/current flow
Describe the concentration of Na+ across membrane?
High extracellular Na+, low intracellular Na+
Describe the effect of potential gradient on Na+?
Moves Na+ extracellularly, opposes concentration gradient
Describe the overall movement of Na+ across membrane?
No net movement, no current flow
Concentration gradient moved Na+ in
Potential gradient moved Na+ out
How do you measure membrane potential?
Use Nernst potential to test which ion it is more selective for
What does high selectivity mean?
More movement (low = less movement)
What happens if you change the electricity of something electrogenic?
Changes membrane potential
Which ion is cell more selective for, sodium or potassium?
High selectivity for potassium and low for sodium
