Membrane Potential and Plasma Membrane

These flashcards cover key concepts related to membrane potential, the function of the plasma membrane, and the roles of various ions in maintaining membrane potential.

What is membrane potential?

A difference in electrical charge across the plasma membrane due to the separation of opposite charges.

What causes the membrane potential?

It results from differences in the concentration and permeability of key ions.

What does the Na+–K+ pump do?

It actively transports Na+ out of and K+ into the cell, maintaining concentration gradients.

What is the equilibrium potential for potassium (EK+)?

The membrane potential at which the concentration gradient for K+ is balanced by the electrical gradient, typically around -90 mV.

What is the resting membrane potential?

The electrical potential difference across the plasma membrane when a cell is at rest, generally about -70 mV.

Which ion tends to bring the membrane potential to +60 mV?

Sodium ion (Na+).

What happens to the inside of the cell as K+ moves out?

The inside of the cell becomes more negative due to the movement of K+ out, leaving behind negatively charged proteins.

What role do nerve and muscle cells play with membrane potential?

They can rapidly and transiently alter membrane permeabilities to ions, resulting in fluctuations in membrane potential.

Which ion has a higher concentration in the intracellular fluid?

Potassium ion (K+).

Which ions influence the resting membrane potential?

Sodium (Na+) and potassium (K+) ions.