October 12, 2012
Diffusion and Osmosis Shown In Solutions
Section 1: Abstract
This lab, title Diffusion and Osmosis, was centered around the diffusion across a cellular membrane and how exactly materials move and diffuse in concentrations. Both diffusion and osmosis are forms of movement that are part of passive transport dealing with cell membranes. Diffusion is where the solutes move from an area of high concentration to a low concentration. Water goes through the cell membranes by diffusion. Osmosis is specifically the movement of water through membranes. Since osmosis and diffusion are both part of passive transport, this means that they do not require energy or pumps. There are different environments created due to diffusion. There are hypotonic, hypertonic, and isotonic environments. Hypotonic is when the solution has a lower solute concentration compared to the water potential. The hypertonic solution has a higher solute concentration and lower water potential. In an isotonic solution, there is no net movement and there is an equal concentration of solutes and water. In our lab, we modeled diffusion and osmosis with a hospital scenario. It is important for an IV solution to have salts in it so the water and solute can be equal to create an isotonic environment. If there wasn’t, there would either be a hypotonic causing the cell to burst, or there would be hypertonic causing the cell to shrink. We created models of living cells by using dialysis tubing. The dialysis tube represented the cell membrane to act as selectively permeable to water and some solutes. We observed different solutes (NaCl, Ovalbumin, Glucose, Sucrose, and Water) in the dialysis tubing. The problem was what environment the solutes would create and whether water would diffuse in or out of the cell. I predicted that all of the tubes will be in a hypotonic environment after the 30 minutes because there is a higher concentration of water outside the cell....
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