The Movement of Substances Across the Cell Membrane
Write an article on Movement of Substances Across the Cell Membrane. It needs to be at least 1750 words. An analysis of the process of osmosis reveals that it is similar to simple diffusion, with the main difference being the presence of the semi-permeable membrane that only allows the passage of water through to the different concentrations (Sperelakis, 2001). Before the process is explained, it is important to note that the water in the cells will always move from the side with a low solute concentration to the area with a high solute concentration. Logically, it should be noted that as the concentration of the solute increase, so does the concentration of the solution, and across different cells, this causes an imbalance, and equilibrium must be restored. Osmosis then occurs to move the water molecules from the highly concentrated side (with low solvent content) to the lower concentrated side (with high solvent content) until the two sides are equally concentrated. Biologically, the side with a high solvent concentration is called the hypertonic solution, the side with the low solute concentration is called the hypotonic solution and equilibrium solutions are called isotonic solutions.In the hypertonic and hypotonic solutions, more water molecules repeatedly strike the cell membrane from the side with a high solute concentration, meaning that more water molecules will be forced to pass through the pores of the semi-permeable membrane (Sperelakis, 2001). As a result of this, the water molecules move from the side with high water concentration to the side with a low water concentration until the two sides are equally concentrated. The final solution is called an isotonic solution. Looking at the cell membrane itself, it can be seen that its composition allows for the selective movement of only certain substances. The osmotic pressure in the different cells ensures that the process of osmosis is continued until all the cells in the organism are of equal concentrations. As already mentioned, the semi permeability of the cell membrane allows only for the passage of certain particles, and in the case of the organism, it only allows for the passage of water molecules. This means that the process of osmosis is used to equalize the concentration of solutions in the body cells and their environment.