An Overview of Transport Mechanisms in Plants |
1. |
Describe how proton pumps function in transport of materials across plant membranes, using the terms proton gradient, membrane potential, cotransport, and chemiosmosis. |
2. |
Define osmosis and water potential. Explain how water potential is measured. |
3. |
Explain how solutes and pressure affect water potential. |
4. |
Explain how the physical properties of plant cells are changed when the plant is placed into solutions that have higher, lower, or the same solute concentration. |
5. |
Define the terms flaccid, plasmolyze, turgor pressure, and turgid. |
6. |
Explain how aquaporins affect the rate of water transport across membranes. |
7. |
Name the three major compartments in vacuolated plant cells. |
8. |
Distinguish between the symplast and the apoplast. |
9. |
Describe three routes available for lateral transport in plants. |
10. |
Define bulk flow and describe the forces that generate pressure in the vascular tissue of plants. |
11. |
Relate the structure of sieve-tube cells, vessel cells, and tracheids to their functions in bulk flow. |
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Absorption of Water and Minerals by Roots |
12. |
Explain what routes are available to water and minerals moving into the vascular cylinder of the root. |
13. |
Explain how mycorrhizae enhance uptake of materials by roots. |
14. |
Explain how the endodermis functions as a selective barrier between the root cortex and vascular cylinder. |
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Transport of Xylem Sap |
15. |
Describe the potential and limits of root pressure to move xylem sap. |
16. |
Define the terms transpiration and guttation. |
17. |
Explain how transpirational pull moves xylem sap up from the root tips to the leaves. |
18. |
Explain how cavitation prevents the transport of water through xylem vessels. |
19. |
Explain this statement: “The ascent of xylem sap is ultimately solar powered.” |
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The Control of Transpiration |
20. |
Explain the importance and costs of the extensive inner surface area of a leaf. |
21. |
Discuss the factors that may alter the stomatal density of a leaf. |
22. |
Describe the role of guard cells in photosynthesis-transpiration. |
23. |
Explain how and when stomata open and close. Describe the cues that trigger stomatal opening at dawn. |
24. |
Explain how xerophytes reduce transpiration. |
25. |
Describe crassulacean acid metabolism and explain why it is an important adaptation to reduce transpiration in arid environments. |
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Translocation of Phloem Sap |
26. |
Define and describe the process of translocation. Trace the path of phloem sap from a primary sugar source to a sugar sink. |
27. |
Describe the process of sugar loading and unloading. |
28. |
Define pressure flow. Explain the significance of this process in angiosperms. |