Cells have methods other than diffusion/osmosis to move materials across the cell membrane, most of which involve membrane proteins and require the use of energy (remember active transport?). The cell membrane also performs functions other than controlling the movement of materials into and out of the cell, and the membranes of some specialized cells have very complex functions. So we can see that the cell membrane is a very intricate and important component of the cell.

In the next experiment, we will simulate diffusion across a cell membrane (Osmosis) using dialysis tubing, another type of differentially permeable membrane.

Lab exercise - Dialysis (click the red button to start the exercise, click again to continue).