Lab 1.docx - Background In this experiment we explored diffusion through dialysis tubing We placed a bag of glucose and starch into a beaker filled with

Lab 1.docx - Background In this experiment we explored...

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Background: In this experiment, we explored diffusion through dialysis tubing. We placed a bag of glucose and starch into a beaker filled with distilled water and Lugol’s solution (IKI) and observed the diffusion of molecules out and into the bag. Procedure: 1. Obtain a 20-cm piece of 2.5-cm dialysis tubing that has been soaking in water. Tie off one end of the tubing to form a bag. To open the other end of the bag, rub the end between your fingers until the edges separate. 2. Test the 15% glucose/1% starch solution for the presence of glucose. Your teacher may have you do a Benedict’s test or use glucose Testape® or Clinistix®. Record the results in Table 1.1. 3. Place 15 mL of the 15% glucose/1% starch solution in the bag. Tie off the other end of the bag, leaving sufficient space for the expansion of the contents in the bag. Record the color of the solution in Table 1.1. 4. Fill a 250-mL beaker or cup two-thirds full with distilled water. Add approximately 4 mL of Lugol’s solution to the distilled water and record the color of the solution in Table 1.1. Test this solution for glucose and record the results in Table 1.1. 5. Immerse the bag in the beaker of solution. 6. Allow your setup to stand for approximately 30 minutes or until you see a distinct color change in the bag or in the beaker. Record the final color of the solution in the bag, and of the solution in the beaker, in Table 1.1. 7. Test the liquid in the beaker and in the bag for the presence of glucose. Record the results in Table 1.1.

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