lab report 4 jennifer jacob

lab report 4 jennifer jacob - through a selectively...

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Section Name Jennifer Jacob Date March 7, 2010 Instructor Exercise 4 CELL PHYSIOLOGY Review Questions 1. What is a selectively permeable membrane, and why is it so important that the plasma membrane is selectively permeable? A selectively permeable membrane is a membrane that allows the passage of only certain substances, selected on the basis of the size and usefulness of molecules. This is important to keep unwanted molecules out of the cell. 2. Define diffusion. Diffusion is the passive movement of molecules or particles along a concentration gradient , or from regions of higher to regions of lower concentration . 3. Do all molecules diffuse at the same rate? Explain your answer based on the experiment you did in this lab exercise. No, molecules do not diffuse at the same rate. 4. What are two important factors that determine whether or not molecules pass
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Unformatted text preview: through a selectively permeable membrane? Explain your answer. Size and solubility determine whether molecules pass through a selectively permeable membrane because if the molecule is too big or it is not soluble it will not pass through the membrane. 5. Define osmosis. Osmosis is the net diffusion of water across a selectively permeable membrane. 6. Explain how the experiments you performed demonstrated the principle of osmosis. The experiments showed that the solutes affected the concentration and diffusion of water. 7. A potato cube is placed in an unknown solution and weighs significantly more when removed and weighed after one hour. Is the unknown solution hypertonic, isotonic, or hypotonic? isotonic...
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lab report 4 jennifer jacob - through a selectively...

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