Microscope Usage, Cell Structure, Diffusion and Osmosis
Cells have three ways to get things in or out: Diffusion, Osmosis, and Active Transport. In this lab you are going to become familiar with how microscopes work and in doing so explore the inner workings of individual cells.
1. Explain the concept of diffusion and provide an example.
2. Explain the concept of osmosis and provide an example.
3. Explain the concept of active transport and provide an example.
4. What is a concentration gradient? What role does a concentration gradient play in diffusion and osmosis?
5. Explain the concept of semi-permeable membrane. Provide an example of what can and cannot get through a plasma membrane.
6. How do you determine the total magnification?
7. Do you have to use the objective lenses in any specific order? If so, what is the order?
8. As you increase magnification, what happens to the field of view?
9. What two subcellular structures can you see in the elodea slides? What is the function of each of them?
10. What two subcellular structures can you identify in the onion slide? You'll need to click on the "field diameter" link to see the correct slide.
11. What does the condenser diaphragm control on a microscope?
12. When you move the condenser diaphragm what happens to the image?
13. What two subcellular structures can you identify in this human cheek cell slide? Provide the function of each.
14. The following diagram is the same as the protist Euglena on the website. Identify the structure and functions for each structure A-D:
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Structure
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Function
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A
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Fagellum
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Allow the cell to move. |
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B
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Nucleus
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The central of euglena.
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C
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Chloroplast
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Photosynthesis.
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D
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Eyespot
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detects light.
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15. Staphlococcus aureus is made up of 82% H2O, 3% NaCl, 1% KCl, 12% Protein, 2% Nucleic Acid. A company makes and bottles a special marinade that consumers use to prepare food for grilling. The marinade consists of 50% NaCl, 10% Pepper, 20% Vinegar, 20% H2O. For each of the following substances, indicate whether or not it would move, by what process would it move (diffusion or osmosis) and in what direction it would move (into or out from S. aureus).
16. Would S. aureus survive if it contaminated a vat of this marinade? Why or why not?
17. E. coli is made up of 84% H2O, 3% NaCl, 1% KCl, 9% Protein, 3% Nucleic Acid. Pond water composition is 84% H2O, 3% NaCl, 2% KCl, 11% Minerals, soil. For each of the following substances, indicate whether or not it would move, by what process would it move
(diffusion or osmosis) and in what direction it would move (into or out from E. coli).
18. Can E. coli survive in this pond? Why or why not?