Membrane Potential I Flashcards
What will happen if the membrane is permeable to only one ion and impermeable to the counterion?
an electrical charge is established
How much is one mole?
6.02x10^23
An imbalance in the number of cations and anions inside a cell produces the ____.
membrane potential
What does z stand for in the Nernst Equation?
valence of the ion in question
If an ion is at equal concentrations across a membrane, what will be its equilibrium potential?
zero
The ion concentration difference and the electrical potential difference across the membrane govern ______.
passive movement of an ion across the membrane
If the membrane is ______ to both Na+ and Cl-, nothing will happen and the cell will survive.
impermeable
What does T stand for in the Nernst Equation?
temperature
The passive movement of an ion across the membrane is governed by two forces: _____ and _____.
its concentration difference; the electrical potential difference across the membrane
What does R stand for in the Nernst Equation?
the gas constant
____ charge is much stronger than ____ charge.
Electrical; osmotic
How do animal cells solve the problem of controlling their volume?
by surrounding themselves with an external solution that also contains nonpermeating molecules
What if Vm is not the same as ECl?
either a) the membrane is impermeable to the ion or b) the ion must be pumped across the membrane
If the membrane is impermeable to both Na+ and Cl-, _____ and the cell _____.
nothing will happen; will survive
The electrochemical gradient is made by?
The ion concentration difference and the electrical potential difference across the membrane in a cell
If the membrane is permeable to both Na+ and Cl-, they both will ______ and the cell will ______.
diffuse into the cell; burst
A beaker of H2O will osmotically support a column of 1.0M glucose _____ high.
900 feet
What does E stand for in the Nernst Equation?
equilibrium potential in millivolts
E = (RT/zF) lne (Co/Ci)
the Nernst Equation
What does F stand for in the Nernst Equation?
the Faraday constant
Bulk solutions are always electrically _____.
neutral
What does Co stand for in the Nernst Equation?
outside concentration of the ion
What is the equilibrium potential?
electrical potential difference across the membrane that must exist if the ion is to be at equilibrium
What does Ci stand for in the Nernst Equation?
inside concentration of the ion
the Nernst Equation
E = (RT/zF) lne (Co/Ci),
If the membrane is ______ to both Na+ and Cl-, they both will diffuse into the cell and the cell will burst.
permeable
What if Vm is the same as ECl?
no pump is needed to maintain the equilibrium
Membrane potentials are produced by?
an imbalance in the number of cations and anions inside a cell
The ion concentration difference and the electrical potential difference across the membrane combined make ______.
the electrochemical gradient
How do cells maintain ionic equilibrium?
for every charged ion that enters the cell, one of the same charge is pushed out of the cell because like repels like
