9 - Diffusion and membrane potential

Which of the following formulas gives the closest approximation of the membrane potential at all times:

Which of the following formulas gives the closest approximation of the membrane potential at all times:

Goldman equation:

Which of the following equations is used to calculate the diffusion potential for non-selective membrane?

Nernst equation

Which of the following equations is used to calculate the diffusion potential for non-selective membrane?

Nernst equation:

How does the diffusion potential evolve with time?

the potential increases until reaching a maximum value (stationary point) then it decreases back to zero;

What type of membrane allows for the generation of diffusion potential?

A permeable membrane: all ions can pass

What kind of state is established between the extra and the intra-cellular spaces during constant membrane potential?

A stationary state

What conditions are necessary for the generation of diffusion potential?

concentration gradient and ion species with different mobility;

Choose the correct statement:

after reaching a maximum, the diffusion potential decreases to zero ;

Choose the best definition for diffusion:

the directed motion of the molecules of the solute from area with high solute concentration toward area of low solute concentration;

Choose the correct statement regarding the process of diffusion.

the rate of diffusion depends on the concentration gradient;

Which of the following conditions are necessary for the generation of membrane potential?

regulation of ion traffic, and the maintenance of ionic concentration gradients

Choose the correct statement regarding the relative electric load between the extra and the intra- cellular environments during the resting state of the cell:

extracellular space is positive relative to the intracellular space;

Diffusion potential arises in a model system that satisfies the following conditions:

two electrolyte solutions of different initial concentrations (c1 ≠ c2) and different anion and cation mobility (u1 ≠ u2) are separated by a porous membrane;

Membrane potential is defined as:

The potential difference between two points on both sides, and in close proximity, of the cellular membrane

Choose the most precise definition of diffusion:

the spontaneous migration of substance from volume of high concentration into volume of low concentration due to the random thermal motion of the constituent particles;

Diffusion potential is measured with:

voltmeter placed between the two compartments with different concentrations;

How do cells maintain a lower sodium concentration on the intracellular side of the membrane?

with continuous use of energy of ATP;

Equilibrium potential across the membrane is achieved when:

Forces due to concentration gradient = forces due to electric gradient

Membrane potential is measured in units of:

Volts

In a thermodynamic system under constant external conditions, the magnitude of the diffusion potential:

Approaches zero

The magnitude of the diffusion potential in an isolated system which starts with off-equilibrium:

After reaching a maximum it decreases to zero

In a thermodynamic system under constant external conditions, the diffusion potential:

has a different maximum value depending on temperature;

The magnitude of the membrane potential in a thermodynamic system under constant external conditions:

has a different value under different temperature;

OPEN - Why the Na+/K+ ATPase is considered a fundamental factor for the formation of the membrane potential?

● Na+/K+ ATPase maintains the ion concentrations across the membrane as well as osmotic equilibrium

● The main function of the N+/K+ ATPase pump is to maintain resting potential so that the cells will be keeping in a state of a low concentration of sodium ions and high levels of potassium ions within the cell (intracellular).

Open - Sketch the time evolution of the diffusion and the membrane potentials on two separate sketches: