Explain why a symptom of uncontrolled diabetes mellitus causes diuresis.

Lab 2 Effect of High Levels of Glucose on Cells


2, 1 cm thick slices of zucchini or other high water content vegetable

Normal Saline

Petri dish

Paper towels


Electronic scales

Weighing boats


1. Collect the materials.

2. Place a zucchini slice on each half of the petri dish.

3. Place the weighing boat on the scale. Tare the weight.

4. Blot each zucchini slice with a paper towel.

5. Weigh each slice in a weighing boat and record the weight on the data sheet.

6. Place about ¼ tsp of honey on one of the zucchini slices.

7. Place enough normal saline to cover the second zucchini slice.

8. Observe what happens at five minute intervals for 20 minutes

9. Blot the zucchini slices to remove honey/saline.

10. Place in the weighing scale (Don’t forget to tare the weight of the weighing boat.)

11. Record the weight on the data sheet.

Condition Zucchini with Honey Zucchini in Normal (Isotonic) Saline
Initial Weight 7.24 7.26
Final Weight 7.78 7.04
Difference 0.54 0.22
% change* 7.45% -3.03%

% change in weight = (current weight – initial weight) X 100

initial weight

Example: Egg Initial weight of 50g and final weight of 40g

% change in weight = (40 -50)/50 or -10/50 or -.20

-.20 X 100 to convert the decimal amount to % = -20% (minus 20% change)

View the Post-Lab Powerpoint

Graph your data (directions in the post lab Powerpoint).

Analyze your data and interpret your findings. You should refer to your book and the prelab and post lab information to help you answer these questions.

1. Describe what happened to the slice in each solution.

It ]has gotten very stiff to turgor pressure increasing .

2. How does the concept of osmosis explain your finding for both solutions?

3. Why is normal saline considered to be an isotonic solution?

4. What is the tonicity of the honey? Explain your answer.

5. Explain why a symptom of uncontrolled diabetes mellitus causes diuresis.

6. Explain why normal saline is used in IV solutions instead of pure water