Membrane Potential Flashcards
(11 cards)
What is membrane potential?
The electrical charge difference across a cell membrane, typically measured in millivolts (mV).
How is the membrane potential established?
Through ion concentration gradients (like Na+ and K+), selective membrane permeability, and active transport via pumps like Na+/K+ ATPase.
Why is the inside of a resting cell typically negative?
Because more K⁺ leaks out than Na⁺ enters, and negatively charged proteins are trapped inside the cell.
What role do ion channels play in membrane potential?
They allow selective movement of ions across the membrane, influencing the cell’s electrical state.
How does selective membrane permeability affect membrane potential?
he membrane is more permeable to certain ions (e.g., K+), leading to uneven ion distribution and a negative interior.
How does changing ion permeability alter membrane potential?
Opening/closing ion channels changes permeability and ion flow, which shifts the membrane potential.
What is the electrochemical gradient?
The combined effect of the concentration gradient and electrical gradient that drives ion movement across membranes.
What happens if the membrane is not permeable to an ion?
The ion cannot move, regardless of the gradient.
How does ion movement affect membrane potential?
Inflow of positive ions (e.g., Na+) depolarizes the membrane; outflow of positive ions or inflow of negative ions hyperpolarizes it.
