Cell and Molecular Biology Lecture 13: Plasma Membrane - Membrane Potential

Cells have a higher concentration of _____ and a lower concentration of _____ inside the cell.

Potassium, Sodium

What is the cellular membrane very permeable to?

Potassium

What is the cellular membrane much less permeable to?

Sodium

Na+/K+ pumps out ___ Na+ for every __ K+ it brings in

3, 2

What causes the K+ to be drawn into the cell?

Negatively charged proteins

True/False: Potassium channels in the cell membrane are always open

True

Cells have an excess of _____ charges on the outside and an excess of ______ charges on the inside

Positive, negative

How is resting potential generated and maintained?

Sodium-potassium pump

What needs to be reached in order for action potential to be triggered?

Threshold potential

What is the period of resistance to stimulation?

Refractory period

What prevents a stimulus from triggering an action potential during the absolute refractory period?

Na+ gates are open but inactivated