Biology 1, Period 3March 15, 2010
Lab Team: Jason Perez, Kicia Long, Chris McLemore
The purpose of this lab is to observe the acts of passive transport: diffusion and osmosis in a model membrane system. The experiment will show how molecules in solution move from areas of higher concentration to areas of lower concentration. The model membrane is dialysis tubing.
2.5 cm dialysis tubing15% glucose solution glucose test strip
1% starch solutiondistilled waterLugol’s iodine solution
Each member of the lab group will complete the procedures independently 1. Obtain a 30 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. 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 and weight of the bag in a data table. 3. Test the 15% glucose/1% starch solution for the presence of glucose using a test strip. Record the results in the data table. 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 data table. Test this solution for glucose and record the results in data table. 5. Immerse the bag in the beaker of solution.
6. Allow your set-up 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 data table. Weigh the bag and record the weight. 7. Test the liquid in the beaker and in the bag for the presence of glucose using the test tape. Record the results in...