Osmosis Diffusion Essay

Ceciah Lucero Per.1

Osmosis/Diffusion Essay There were many concepts and principle applied in the lab. One concept in the experiment of Osmosis/Diffusion was based on concentration gradient which is the gradual change in the concentration of solutes in a solution as a function of distance through a solution. This results from an unequal distribution of ions across the cell membrane. When this happens, solutes move along a concentration gradient. This kind of movement is called diffusion. Another concept was that the experiment was based on a semi-permeable membrane. For one lab, dialysis tubing was used to resemble a cell body. It was semi-permeable and allowed for certain things to go in and out. The mass of the bags need to be taken before and after experiment to find the change in mass and whether or not molarity increase or decreases mass size. The measurable change in the experiment comes directly from the data. The change in mass for the dialysis bags are results from the experiment. When you graph the molarities of the solutions and the percent changes in masses, one could see that the graph is positively correlated. Another concept applied is water potential which is how water enters a level of high concentration to a lower one and its tendency to do so. In an open system, pressure potential is zero, so when calculating water potential, one must add solute’s potential to the pressure potential. The equation –iCRT is used to find solute potential. Diffusion is the process by which molecules spread from areas of high concentration to areas of low concentration. Although this is similar to osmosis, it is difference in the sense that osmosis is the process by which the net movement of water across a selectively permeable membrane driven by a difference in solute concentrations on the two sides of the membrane. A selectively permeable membrane is one that allows unrestricted passage of water, but not solute molecules or ions. This selective permeability means that the cell membrane has control over what crosses it so that only some molecules can enter or leave the cell. However, some of the factors that control this process of diffusion through the cell membrane are solute size and molar concentration.In order to see its effects, consider that two solutions are separated by a selectively permeable membrane. The one that is hypertonic to the other must have more solute, thus, having less water as well. At standard ideal conditions the water potential of the hypertonic solution is less than the water potential of the hypotonic solution therefore causing the movement of the water to be from the hypotonic solution into the hypertonic solution. This also works with the diffusion through a membrane.