This does not require a supply of energy because diffusion is a spontaneous process. This occurs when molecules are moved across the cell membrane from an area where they are at a low ...

Diffusion is the movement of particles ... and is one of the ways substances can move across the cell membrane, into or out of the cell. Products of digestion, dissolved in water, can pass across ...

Together, these concentration differences create a small electrical potential across the plasma membrane ... process of molecular diffusion. As a consequence, excitable cells respond to signals ...

Cell membranes protect and organize cells. All cells have an outer plasma membrane that regulates not ... which means that some molecules can diffuse across the lipid bilayer but others cannot.