Passive Membrane Properties (Margiotta)

Front 1

Voltage

Back 1

-a transmembrane difference in electrical potential
-a form of potential energy
- V=Q/C

Front 2

Capacitance

Back 2

-the amount of electric charge stored/separated for a given potential
-C=Q/V

Front 3

Resistance

Back 3

-the property of a conductor which impedes charge movement
-R=V/I

Front 4

Current

Back 4

-rate of movement of charge
-I=V/R

Front 5

How selective are voltage gated ion channels?

Back 5

-very selective for their named ions

Front 6

How selective are ligand gated ion channels?

Back 6

-much less selective
-they are more or less "valence" selective (ex. they either select for pos or neg ions)

Front 7

Resting potential

Back 7

-(inside potential) minus (outside potential)

Front 8

Is a cell's resting potential always the same?

Back 8

-no, cells can have different potentials and different times

Front 9

What does the driving force that pushes an ion thru its channel depend on?

Back 9

-the concn gradient of the ion across the membrane
-the potential difference across the membrane

Front 10

Nernst Eqn

Back 10

-predicts the equilibrium potential of an ion across a membrane
-E=(58/z)log{[X2]/[X1]}
-z=ion's valence

Front 11

Goldman Eqn

Back 11

-predicts the value of the membrane potential in a multi ion environment if we know the permeabilities of the membrane to the relative ions

Front 12

What are the concentrations of Na+ and K+ relative to the cell membrane?

Back 12

-high Na+ outside
-high K+ inside

Front 13

Are Ca2+ levels higher inside or outside of the cell at rest?

Back 13

-outside

Front 14

Where do ion exchange pumps get their energy?

Back 14

-by using the electrochemical gradient of other ions, usually Na+

Front 15

Which way does the Na+/K+ pump move each ion?

Back 15

-Na+ out
-K+ in
-restores resting potential after an action potential