Osmosis and diffusion report sheet
- Osmosis
Experiment (dry lab)
There are 3 diagrams of animal cells (a, b, c) and 3 diagrams of plant cells (a, b, c) in solutions of varying tonicity. Label the diagrams as isotonic solution, hypertonic solution, or hypotonic solution.
|
Animal cells: | |
|
(a) |
Hypotonic |
|
(b) |
Isotonic |
|
(c) |
Hypertonic |
|
Plant cells: | |
|
(a) |
Hypotonic |
|
(b) |
Isotonic |
|
( c) |
Hypertonic |
- Effect of temperature and size
Observe the agar plate at 25°C, 30 min.
Experiment (dry lab)
|
Potassium permanganate at 25°C |
Janus Green at 25°C | ||
|
Time |
Distance in mm |
Time |
Distance in mm |
|
30 min |
25 |
30 min |
20 |
Potassium permanganate (294 Daltons) and Janus Green (511 Daltons) dyes
|
Which dye has greater diffusion, potassium permanganate or Janus Green? |
Potassium Permanganate |
|
Why? |
The molecular weight of Potassium Permanganate is less so it diffuses quicker. |
Observe the agar plate at 5°C, 30 min.
Experiment (dry lab)
|
Potassium permanganate at 5°C |
Janus Green at 5°C | ||
|
Time |
Distance in mm |
Time |
Distance in mm |
|
30 min |
23 |
30 min |
18 |
Potassium permanganate (294 Daltons) and Janus Green (511 Daltons) dyes
|
Which dye has greater diffusion potassium permanganate or Janus Green? |
Potassium Permanganate |
|
Why? |
The molecular weight of Potassium Permanganate is less so it diffuses quicker. |
Compare the agar plates at 5°C and 25°C.
Experiment (dry lab)
|
Which agar plate shows greater diffusion, 5°C or 25°C? |
Potassium Permanganate |
|
Why? |
The molecular weight of Potassium Permanganate is less so it diffuses quicker. |
Effect of temperature on diffusion of iodine
Experiment (at home lab)
QUESTIONS
|
Temperature of your cups: |
169°C |
25°C |
|
Is the food coloring evenly distributed in each? |
No | |
|
Explain. |
Higher temperatures tend to increase rate of diffusion (which will distribute evenly) | |
- Effect of solute concentration
Experiment (dry lab)
In the weight change column, record if the bag should increase in weight, decrease in weight, or stay about the same.
|
# |
Bag contents |
Beaker contents |
Weight change |
Beaker contents |
|
1 |
10 ml Distilled water |
200 ml Distilled water |
Same |
Hypertonic |
|
2 |
10 ml 10% sucrose |
200 ml Distilled water |
Increase |
Isotonic |
|
3 |
10 ml 20% sucrose |
200 ml Distilled water |
Increase |
Isotonic |
|
4 |
10 ml 40% sucrose |
200 ml Distilled water |
Increase |
Isotonic |
|
5 |
10 ml Distilled water |
200 ml 40% sucrose |
Decrease |
Hypotonic |
|
Which bag should gain the most weight? |
4 | |||
- Differential permeability of membranes
Experiment (dry lab)
|
Test for |
Is test positive or negative? |
|
Starch |
Negative |
|
Protein |
Negative |
|
Chloride ion |
Positive |
|
Sulfate ion |
Positive |
|
Which ones (starch, protein, chloride ions, sulfate ions) moved through the dialysis tubing and into the beaker? |
Chloride ions and Sulfate Ions |
|
Why did some not move from the bag into the beaker? |
They were too big to pass through the membrane. |
- Diffusion and osmosis in living cells
Experiment (dry lab)
- Osmosis with red blood cells
|
Describe the blood cells. | |
|
0.9% NaCl , Normal blood cells |
Round shapes with something that looks like a nucleus in the middle |
|
10% NaCl, Crenated cells |
Shriveled almost popcorn looking |
|
1. What solution causes cells to appear this way? Isotonic, hypertonic or hypotonic solution. |
2. What solution causes cells to appear this way? Isotonic, hypertonic or hypotonic solution. |
|
Hypertonic |
Isotonic |
- Osmosis with plant cells
|
Describe the plant cells. | |
|
0% NaCl, Turgid cells |
Chloroplasts are pushed out to periphery of cell |
|
20% NaCl, Plasmolyzed cells |
Chloroplasts are pushed to center of cell |
|
1. What solution causes cells to appear this way? Hypertonic or hypotonic solution. |
2. What solution causes cells to appear this way? Hypertonic or hypotonic solution. |
|
Hypotonic |
Hypertonic |
Diffusion in cucumber cells
Experiment (at home lab)
QUESTIONS
|
1. When comparing the firmness of the cucumber slices, how would you describe each, firm (turgid cells) or soft (plasmolyzed cells)? | |
|
Cup 1 |
Turgid Cells |
|
Cup 2 |
Plasmolyzed Cell |
|
Cup 3 |
Turgid Cell |
|
2. What caused one to be firm and the other to be soft? Explain. |
The salt forced the water out of the cucumber cells causing them to become flaccid. |
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