How does the cellular process of osmosis occur?

Question

How does the cellular process of osmosis occur?

Answer 1

Osmosis is the diffusion of water.  Diffusion is the passive transport of molecules.  What makes it passive is that no added energy is required.  It relies completely on the energy embodied in molecular movement.  Because this molecular movement is random, over time molecules will have a net movement from an area of higher concentration to an area of lower concentration.

So, in cells, osmosis occurs when water moves passively into or out of a cell with the concentration gradient (i.e., from area of high to low concentration).  Water is able to move passively into and out of a cell because the outer layers of the cell membrane are polar and hydrophilic, allowing the polar water molecule to cross.