Experiment 2: Concentration Gradients and Membrane Permeability
In this experiment, you will dialyze a solution of glucose and starch to observe:
The directional movement of glucose and starch.
The effect of a selectively permeable membrane on the diffusion of these molecules.
An indicator is a substance that changes color when in the presence of a specific substance. In this experiment, IKI will be used as an indicator to test for the presence of starch.
Materials
(5) 100 mL Beakers
10 mL 1% Glucose Solution, C6H12O6
4 Glucose Test Strips
(1) 100 mL Graduated Cylinder
4 mL 1% Iodine-Potassium Iodide, IKI
5 mL Liquid Starch, C6H10O5
3 Pipettes
4 Rubber Bands (Small; contain latex, handle with gloves on if allergic)
Permanent Marker
*Stopwatch
*Water
*Scissors
*15.0 cm Dialysis Tubing
*You Must Provide
*Be sure to measure and cut only the length you need for this experiment. Reserve the remainder for later experiments.