Membrane potential Flashcards
Do all cells have a membrane potential?
Yes
What causes a membrane potential
The ions being unevenly distributed outside and inside the cell which creates a potential difference
There is a high concentration of —– and —– oustide the cell (extracellular)
Na+ and Cl- oustide the cell
There is a high concentration of —– and —– inside the cell (intracellular)
K+ and anions inside the cell (intracellular)
The high concentration of Na and Cl outside the cell and high concentration of K and anions inside the cell creates what
It creates an electrochemical gradient across the plasma membrane.
what is a resting membrane potential
It is the membrane potential of a cell when its inactive.
What causes a change in membrane potential
When the cells becomes more permeable to particular ions so the ions are able to move across a membrane.
Each ion has its own equilibrium potential. what is an equilibrium potential.
Its the point where there would be no net movement of an ion across a membrane.
what is the equilibrium potential of Sodium
+60mV
what is the equilibrium potential of potassium
-80mV
what is the equilibrium potential of a neuron
- 70mV
What do ion channels do
They facilitate diffusion
What are ion channels made up of
several protein subunits which cross the cell membrane
Why are ion channels highly selective for ions to pass through them
because of their pore size (how wide open they are) and the properties of the amino acids that form the pore.
Name the two ways ion channels can be opened.
Ligand gated ion channel and Voltage gated ion channel
