The cell and its extracellular environments are fluid in that concentrations of substances dissolved in it vary. Depending on varying concentration of the substances dissolved in water, be it extracellular or intracellular, dissolved substances or water move from one compartment to another directed by physical principles of gradients. To accomplish this, the cell utilizes the processes of osmosis and diffusion as appropriate. These phenomena can be visualized outside the cell by simulating these in vitro. Since cell membrane is a semipermeable membrane and exchanges occur through this, these experiments must utilize a construct of the semipermeable membrane that can be made with a commercially available dialysis tubing and bag. These membranes have microscopic pores through which small molecules like water can pass, but larger molecules, such as sugar cannot pass through them. Thus through this molecular net, solutions of different solute concentrations can be observed to pass in a measurable fashion. This experiment has been designed to prove the hypothesis of the mechanisms of osmosis and diffusion through such a semipermeable membrane.
Diffusion is defined as the movement of molecules from a site of higher concentration to that of a lower concentration. Technically speaking, this difference in concentration creates a concentration gradient, and the steepness of the gradient determines the rate of diffusion. ...Show more