Membrane potential Flashcards
What are the two ways in which ions are separated?
diffusion or through ion channels
What is the voltage at the outside of the cell?
Zero, by convention
The inside of a cell at
rest is always [blank] relative to the outside, so the cell’s membrane potential is a
[blank] number.
The inside of a cell at
rest is always negative relative to the outside, so the cell’s membrane potential is a
negative number.
What are the two forces that act on an ion?
The electric, and the chemical
What causes the electrical driving force?
unequal distribution of ions
If a cells membrane potential is negative, where will cations be drawn to?
Inside the cell
Assume that a cell membrane is only permeable to K. What will happen?
K will diffuse out until chemical and electrical forces are balanced.
What is the equilibrium potential of an ion, e.g. E(K+)?
The potential (V) of an ion
What is the Nernst equation?
Look at it!
Where does the membrane potential fall, relative to the equilibrium potentials for Na and K?
Between them, but closer to Ek d/t a higher number of K transporters
True or false: Ek changes with [K] changes
True
What happens when an action potential to the Na and K ions?
the membrane becomes more permeable to Na
When is the Goldman-Hodgkin equation used?
When there are several ions affecting the resting membrane potential
Look at the GHK equation
look at it
As the relative permeability of the membrane to an ion increases, the
membrane potential of the cell moves closer to what?
the equilibrium potential of that ion.
