Electrochemical Gradients Flashcards
bongo knows
What is the membrane potential of a cell caused by?
It is caused by the separation of positive and negative charges by the plasma membrane.
What are high in concentrations in the ECF
Chloride and sodium ions
What are in high concentrations in the ICF/ Cytosol
Potassium ions and negatively charged proteins.
Can the ions cross freely cross the lipid portions of the plasma membrane?
No
How can they enter/exit?
They can exit or enter through membrane channels using active transport mechanisms.
What two ions mostly affect membrane potential?
K+ and Na+ ions
How do potassium ions get out of the cell?
The diffuse out of the cell through potassium leak channels
What does the sodium-potassium exchange pump do?
The pump ejects 3Na+ for every 2K+, it rests at -70mV, this helps maintain a stable resting membrane potential.
How do sodium ions get into the cell?
Sodium ions can diffuse into the cell through sodium leak channels.
What is the range of the different membrane potentials?
-5 mV to -100 mV.
What does the negative sign mean?
It indicates that the interior is negatively charged.
How do negatively charge proteins affect the cells and why are they important?
The proteins are in large abundances in the inner membrane as they can not cross over, this causes am important electrical force involved in Na+ and K+ movement.
