Diffusion and Osmosis of Solutes and Water Across a Membrane

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Diffusion and Osmosis of Solutes and Water Across a Membrane
Brittany Bacallao
Nova Southeastern University

This experiment gave a visual understanding of osmosis and diffusion. The first experiment proved that solutes would move down a concentration gradient if permeable to the selective membrane. The second experiment proved different solute concentrations affect the movement of water, depending on the solute concentration inside the cell. The purpose of this lab was to look for different solutes that can cross an artificial membrane and to observe the effect of different concentrations of sucrose on the mass of a potato cell. Results for Part One suggested that the molecular weight of albumin and starch was too large to
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The weight obtained was recorded as initial weight. While weighing the dialysis tube with the solution of starch and sodium sulfate, eight test tubes were obtained and solution of starch/sodium sulfate was added to two test tubes labeled bag start (Keith et al., 2010). After weighing dialysis tubing of starch/sodium sulfate and adding the solution to two test tubes, the tubing was placed in a beaker containing a solution of albumin and glucose. Next, 1.0 mL of albumin and glucose were then placed in two test tubes labeled solution start. The tubing in the albumin/glucose solution was kept inside the solution for 75 minutes. Every 15 minutes the solution and tube was mixed (Keith et al., 2010). At the end of the 75 minutes, two 1.0 mL samples of the albumin/glucose solution from the beaker were added to two test tubes labeled solution end. Then, the dialysis tube was removed from the beaker and rinsed off with distilled water. Once the tubing was rinsed and blotted dry the final water weight was recorded. After measuring the final water weight, the contents in the tubing was dumped into a beaker and 1.0 mL of starch/sodium sulfate solution was added to two test tubes labeled bag end (Keith et al., 2010). In order to test for glucose, a glucose dip and read strip was placed in the first set of test tubes that were labeled bag start, solution start, bag end, and solution end. Then, a protein dip-and-read strip was placed in the same set
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