Diffusion, Osmosis and Cell Membranes All living things have certain requirements they must satisfy in order to remain alive. These include exchanging gases (usually CO2 and O2), taking in water, minerals, and food, and eliminating wastes. These tasks ultimately occur at the cellular level, and require that molecules move through the membrane that surrounds the cell. This membrane is a complex structure that is responsible for separating the contents of the cell from its surroundings, …showed first 75 words of 2855 total…

…showed last 75 words of 2855 total…enters the cell by osmosis. The smaller the concentration of water in the external solution the greater the amount of water that leaves the cell. However, there will be a point where the concentrations of water inside and outside the potato cells are equal (isotonic). At this point there will be no change in the length, volume and mass of the potato, as the net movement of water will be zero, no osmosis has occurred.