Dialysis Lab
Purpose: To observe how molecules diffuse in or out of a cell
across the cell membrane.
Question: Will glucose, starch and iodine (potassium iodide) readily pass
through the pores of the dialysis tubing?
Hypothesis: _______________________________________ will readily
pass through the membrane of the dialysis tubing.
_______________________________________ will NOT readily pass
through the membrane of the dialysis tubing.
Materials:
https://williambiolabreports.wordpress.com/2014/11/01/diffusion-via-dialysis/
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Dialysis tubing
- sugar solution
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String
- starch solution
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Iodine
- 2 breakers
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Glucose
Part A:
described during the pre-lab discussion.
1.
2.
3.
4.
5.
Make a “cell” out of the dialysis tubing, as
Add approximately 10mL of starch solution into the tube and seal it by tying it shut.
Place the “cell” into the beaker of water and add iodine.
Make a drawing of your apparatus.
Write down the time:____________Set beaker A to the side and begin part B of the procedure.
After 20 minutes, draw your observations.
Part B:
1. Make a “cell” out of the dialysis tubing, as described during the pre-lab
discussion.
2. Add approximately 10mL of sugar solution into the tube and seal it by tying it shut.
3. Place the “cell” into the beaker of water and add iodine.
4. Write down the time:____________
5. Make a drawing of your apparatus. After 20 minutes, draw your observations.
6. Use glucose strips to test the solution in the beaker for glucose after the 20 minutes has elapsed.
Analysis:
1. Beside your original drawings of the apparatus, draw your observations after 20 minutes.
2. Which molecules moved in across the membrane in Part A? Did the molecules move in or out of the
tube (cell)? How can you prove this?
3. Which molecules moved across the membrane in Part B? Did the molecules move in or out of the tube
(cell)? How can you prove this?
4. What does this experiment tell us about the size of the glucose, starch and iodine molecules compared
to the pore size in the dialysis tubing?
5. What type of solution was present in Part A? Part B?
WHAT TO HAND IN: Copy / Trace the diagram of the beaker to the right 
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Formal Lab Write-up
Include before and after labelled drawings of your apparatus
Include your discussion questions & conclusion