Transcript Chapter 5
Chapter 36 Transport in Plants Active Lecture Questions for use with Classroom Response Systems Biology, Seventh Edition Neil Campbell and Jane Reece Edited by William Wischusen, Louisiana State University Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 1. What mechanism explains the movement of sucrose from source to sink? a) evaporation of water and active transport of sucrose from the sink b) osmotic movement of water into the sucrose-loaded sieve-tube members creating a higher hydrostatic pressure in the source than in the sink c) tension created by the differences in hydrostatic pressure in the source and sink d) active transport of sucrose through the sieve-tube cells driven by proton pumps e) the hydrolysis of starch to sucrose in the mesophyll cells that raises their water potential and drives the bulk flow of sap to the sink Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 2. The main mechanism(s) determining the direction of short-distance transport within a potato tuber is (are) a) diffusion due to concentration differences and bulk flow due to pressure differences. b) pressure flow through the phloem. c) active transport due to the hydrolysis of ATP and ion transport into the tuber cells. d) determined by the structure and function of the tonoplast of the tuber cells. e) not affected by temperature and pressure. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 3. A water molecule could move all the way through a plant from soil to root to leaf to air and pass through a living cell only once. This living cell would be a part of which structure? a) the Casparian strip b) a guard cell c) the root epidermis d) the endodermis e) the root cortex Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 4. Photosynthesis begins to decline when leaves wilt because a) flaccid cells are incapable of photosynthesis. b) CO2 accumulates in the leaves and inhibits photosynthesis. c) there is insufficient water for photolysis during light reactions. d) stomata close, preventing CO2 entry into the leaf. e) the chlorophyll of flaccid cells cannot absorb light. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 5. Which of the following experimental procedures would most likely reduce transpiration while allowing the normal growth of a plant? * a) subjecting the leaves of the plant to a partial vacuum b) increasing the level of carbon dioxide around the plant c) putting the plant in drier soil d) decreasing the relative humidity around the plant e) injecting potassium ions into the guard cells of the plant Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 6. Water flows into the source end of a sieve tube because a) sucrose has diffused into the sieve tube, making it hypertonic. b) sucrose has been actively transported into the sieve tube, making it hypertonic. c) water pressure outside the sieve tube forces in water. d) the companion cell of a sieve tube actively pumps in water. e) sucrose has been dumped from the sieve tube by active transport. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 7. In the pressure-flow hypothesis of translocation, what causes the pressure? a) root pressure b) the osmotic uptake of water by sieve tubes at the source c) the accumulation of minerals and water by the stele in the root d) the osmotic uptake of water by the sieve tubes of the sink e) hydrostatic pressure in xylem vessels Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings