Diffusion and Osmosis
In this lab we will observe the process of diffusion and osmosis and also learn the effect of solute concentration to water potential to living plant tissue.
The lab shows how each solutions differ, having high and low concentrations. We see how diffusion and osmosis works. Water moves from higher to lower concentration. Higher concentrations lose water to lower concentrations.
We all know that molecules are everywhere. They are just out there smashing into each other. But, how do they work ? Do they have a system of knowing where to be at the right time ? How are they being regulated ? All the ...view middle of the document...
get 30cm of 2.5cm dialysis tubing that has been soaking. Tie one end shut. 2. Test 15% glucose/1% starch solution for prescence of glucose. 3. Place 15mL of 15&glucose and starch solution. Then tie other end,. Make sure you leave a little space. 4. Fill 250mL beaker 2/3 full with distilled water. Add about 4mL of Lugol's solution to distilled water. Test for glucose. 5. Immerse bag into beaker. 6. Wait for change in color or about 30 minutes. Record data. 7. Test liquid from the beaker and bag for any traces of glucose.
1.Get 3 pre-soaked dialysis tubing. 2. Tie know on one end of them and fill each tubing with 6. record data.15-25mL of assigned surcrose solution. Remove as much air from bag as possible and tie on other ends. 3. Rinse each bag. $, Carefully dry bag and weigh them in grams. Fill each beaker distilled water. Make sure they are completely submerged. 4. Let it stand for 30 minutes 5. After 30 minutes dry bag and measure.
C Water Potential
First, slice the potato into to 3-cm discs. Use the potato corer to core out 12 cores. 2.Weigh 4 cores together and record their mass. 3. Fill each cup with one of the following solutions: distilled water, 0.2 M glucose, 0.4 M glucose, 0.6 M glucose, 0.8 glucose, and 1.0 M glucose. 4. In each cup put 4 potato cores, and allow them to sit over night. Take out the cores and blot them dry. 5.Again weigh them on the electronic scale. Record the change in mass. 6. Calculate the information for the table. Compare the results with another group.
Calculation of Water Potential from Experimental Data
1.determine the solute potential of the glucose solution the pressure potential, and the water potential. 2. calculate 3. Graph the information given about the zucchini cores.
E. Onion Cell Plasmolysis
Prepare a wet mount slide of dyed onion skin. 2. Observe under a light microscope and sketch how the cells appear. 3. Add a few drops of the salt solution using a paper towel to wick the solution under the slip. 4. Observe how the cells are effected and make another sketch.
Overall the lab was a success. As the solution cups were left for the appointed time with either the bags or potato cores, the solution bags that were lower then the percentage of solution then outside, water soaked up solution. The bags that were higher than the percentage of a solution outside the bag decreased in content.
| |Initial Contents |Solution |Color |Presence of |Glucose |
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