Transport Through The Cell Membran
mattymatt121
QuestionsfortheTransportthroughtheCellMembraneHandoutdraft5.docxQuestions for the Transport through the Cell Membrane Handout
Name _________________________
Total points = 72
Grade = your score/total points
1. Explain the specific reasons why it is necessary for the cell membrane to control the transport of substances into and out of the cell. Define selectively permeable. Identify the essential substances that must be moved into the cell and the waste products that must be moved out. 6 points
2. Compare active transport and passive transport. Include in your comparison energy requirements for each and the difference in the direction of transport with regard to concentration gradient. 4 points
4. Assume you have a U-shaped glass tube. A membrane permeable to both sucrose and water separates side A from side B. At the beginning of the experiment, the concentration of sucrose on side A is 10%. The solution of sucrose on side B is 30%. The tube is allowed to stand for one hour. What is the transport process that takes place? Support your answer by giving the reason that it is that process. Describe the direction of diffusion of sucrose; do the same for water. At the end of the experiment, what will be the concentration of sucrose on side A, on side B? 10 points
5. What is the effect of a) concentration gradient, b) molecular weight and c) temperature on the diffusion of substances? 6 points
6. Define: facilitated diffusion. Compare facilitated diffusion to a) ordinary diffusion and b) active transport. 6 points
7. Define osmosis. 2 points
8. Assume you have a U-shaped glass tube. A membrane permeable to water but not permeable to sucrose separates side A from side B. At the beginning of the experiment, the concentration of sucrose on side A is 40%. The concentration of sucrose on side B is 20%. The tube is allowed to stand for one hour. What transport process is this? Support your answer by giving the reason that it is that process. Describe the direction of movement of water; do the same for the sucrose. At the end of the experiment will the concentrations of the water and the sucrose come to an equilibrium and become equal on both sides? Why or why not? 10 points
9. Define isotonic, hypertonic, and hypotonic solutions. Explain what happens to a red blood cell placed in a) a 10% salt solution, b) a 0.9% salt solution and c) a pure (100%) water solution. Identify each solution as isotonic, hypertonic or hypotonic. 12 points
10. Define plasmolysis. A plant cell such as an Elodea cell is examined first in a drop of plain water, and is then examined as a drop of 20% salt solution replaces the drop of plain water on the microscope slide. Describe the changes in the cell that would be visible under the microscope. Based on your understanding of osmosis, explain those changes. 6 points
11. Define active transport. 2 points
