Membrane Potentials and Equilibrium

Flashcards covering key concepts and vocabulary related to membrane potentials, ion equilibrium, and metabolic rates based on the lecture notes.

Membrane potential (V)

The actual electric potential difference across the membrane, measured in millivolts (mV).

Resting membrane potential

The stable membrane potential calculated using the formula ψm≈60∙log PK[Kout] + PNa[Naout] + PCl[Clin] / (PK[Kin] + PNa[Nain] + PCl[Clout]).

Graded potential

A membrane potential that can assume a range of values without a specific symbol.

Action potential

A self-sustaining traveling depolarizing potential.

Equilibrium potential

A virtual quantity at which a given ion would be at equilibrium; cannot be directly measured, expressed as yeq = (60/z)*log(Cout/Cin).

Equilibrium potential for Na+

For a positive ion, if it is +30 mV, then the concentration is higher outside the cell.

Equilibrium potential for K+

For a positive ion, if it is -30 mV, then the concentration is higher inside the cell.

Equilibrium potential for Cl-

For a negative ion, if it is -30 mV, then the concentration is higher outside the cell.

Movement of ions through channels

Movement direction is determined by comparing equilibrium potential and membrane potential.

Na+/K+ pump

A pump that moves 3 sodium ions out and 2 potassium ions into the cell, essential for maintaining resting potential.

Osmolarity

A measure of solute concentration defined as the total number of solute particles in a liter of solution.

Molar concentration

Approximation of the number of molecules in a liter of solution.

pH scale

A measure derived from the concentration of hydrogen ions [H+]; pH 7 corresponds to a concentration of 0.1 mM.

Microscopic images in biology

Illustrative representations that convey information about cell structures at different scales.

Mass-specific metabolic rate

The amount of oxygen consumed per gram of organism per hour, crucial for understanding metabolic rates.