Biology 1020 Diffusion and Osmosis Lab Report

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Submitted By kaeskola
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Pages 4
Kristina Eskola
BL 1020
Diffusion and Osmosis Lab Report (Dialysis)
Dialysis Tubing is a membrane made of regenerated cellulose fibers formed into a flat tube. If two solutions containing dissolved substances of different molecular weights are separated by this membrane, some substances may readily pass through the pores of the membrane, but others may be excluded.
We will be investigating the selective permeability of the tubing to reduce sugar, glucose, starch, and iodine potassium iodide. We will test this by placing a solution of glucose and starch into a dialysis tubing bag and then place this bag into a solution of iodine potassium iodide (I2KI).
Prediction: The I2KI solution will turn blue when adding Benedict’s reagent.
Hypothesis: The solution of water and I2KI will be the most permeable because they will mix and react with Benedict’s reagent and the heat so the cell membrane only allows certain molecules to enter and leave the cell
Materials and Methods: In the experiment we will be using two tests. In the first test, we will be using I2KI to test for the presence of starch. When I2KI is added to an unknown solution, the solution will turn purple or black if starch is present. If there is no starch in the solution, it will remain pale yellow. In the second test we will be using Benedict’s test for reducing sugar. When Benedict’s reagent is added to an unknown solution and the solution is heated, it will turn green, orange or orange-red if sugar is present. If no sugar is present in the solution, it will remain blue. The materials needed for this experiment are the 30% glucose substance, starch solution, I2KI solution, Benedict’s reagent, hot plate, 500 mL beaker with water, test tube holder, 3 test tubes, pipettes, 2 400 mL beakers, and a strip of moist dialysis tubing.
Procedure: The first thing we did was prepare the…...

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