Cell Membrane, Membrane Transport, and Membrane Potential 5 Flashcards
What a membrane potential?
charge difference across the plasma membrane
What creates the membrane potential ?
unequal distribution of anions and cations across the cell membrane
What does the charge separate create?
a source of energy
What is resting membrane potential?
charge difference across the plasma membrane when the cell is at rest
What is the normal resting potential?
-70mV
What does the sign of the number represent?
the charge inside of the cell
What does the membrane potential help to regulate?
the opening and closing of ion gated channels and exocytosis
What two gradients help with the passive transport of charged substances across the membrane?
chemical and electrical gradient
What is the chemical gradient?
concentration gradients that allow ions to flow down
What is the electrical gradient?
changes in charge that allow ions to flow down
What does the strength of the electrical gradient depend on?
the valence of the ions and the magnitude of the membrane potential
What can help to increase the driving force of ions?
greater membrane potential and greater valence of ions
What is the equilibrium potential?
membrane potential creates a difference in electrical gradient that is equal and strength but opposite in direction of the concentration gradient
What does the nerst equation calculate?
the equilibrium potential when ion concentrations are known
