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Science
Grade: Senior
Subject: Science

#4112. Cell Membrane Osmosis Lab

Science, level: Senior
Posted Thu Feb 14 17:15:05 PST 2008 by Support (support@lessonplansinc.com).
Cell Biology Lesson Plans
Lesson Plans Inc., Concord, CA
Materials Required: Elodea plant, water, salt, beakers, pipettes, microscopes, slides, cover slips, distilled water
Activity Time: 90 minutes
Concepts Taught: Osmosis, cell membrane, diffusion, water transport

1. You and your lab partner are assigned to a particular microscope. May only use this microscope and not touch another student's microscope with out teacher permission.

2. Clean the microscope objectives and eyepiece using the special microscope cloth.

3. One group member may go to the Elodea station with a pipette. Make a wet mount slide using pond water and Elodea. Place a drop of pond water onto the center of a slide. Place a small piece of Elodea onto the drop. Place the cover slip on top of the water. It is important to place cover slip on the edge of the water at a 45-degree angle. Then lower the cover slip slowly to prevent air bubbles. If you get any air bubbles, you need to tap the cover slip and use a paper towel to remove the excess water.

4. While starting with the lowest objective, focus the microscope using the course objective. Then focus the microscope with the medium objective. Then focus with the highest objective using the fine adjustment only.

5. Draw four cells and label the cell wall, cytoplasm, central vacuole, and the chloroplast in circle #1.

6. Remove the cover slip and blot the pond water with a paper towel. Place a drop of saline solution onto the Elodea leaf and replace the cover slip. Focus the microscope, starting with the lowest objective and leading your way to the highest power.

7. Watch what happens to the central vacuole. It may take one or two minutes. Draw and label the four cells once again in circle #2.

8. Remove the cover slip and blot the pond water with a paper towel. Place a drop of distilled water onto the Elodea leaf and replace the cover slip. Focus the microscope, starting with the lowest objective and leading your way to the highest power.

9. Watch what happens to the central vacuole. It may take one or two minutes. Draw and label the four cells once again in circle #3.