Bio Ch36 Pretest – Flashcards
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The proton pump _____.
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uses the energy stored in ATP to produce a hydrogen ion gradient
( This proton gradient occurs across a membrane)
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A plant cell placed in a solution with a lower water potential will _____.
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lose water and plasmolyze
( Water moves from a region of higher water potential to a region of lower water potential. Loss of water pulls the plasma membrane away from the cell wall, producing plasmolysis.)
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The water potential of a cell is defined by the equation Ψ = Ψs + Ψp. Which of the following statements is true?
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Ψp may be either positive or negative.
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Which of the following is a correct statement about a difference between xylem and phloem transport?
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Xylem sap moves up; phloem sap moves up or down.
( The direction of movement in xylem is from roots to leaves. Phloem sap is transported throughout the plant from source to sink.)
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Which one of the following refers to the loss of water through the stomata in a plant's leaves?
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transpiration
( The stomata in the leaves are entry points for the carbon dioxide necessary for photosynthesis, but they are also exit points for the evaporation of water by transpiration.)
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The last thing all water and solute molecules pass through before they enter the vascular system of roots and move upward to the leaves is _____.
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an endodermal cell
( The endodermis is the innermost layer of the root cortex and surrounds the vascular tissue.)
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The Casparian strip is _____.
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a band of waterproof suberin impregnated through endodermal cell walls.
( Within the wall of each endodermal cell is the Casparian strip, a belt of waxy material that blocks the passage of water and dissolved minerals.)
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A student is performing a chemical analysis of xylem sap. This student should not expect to find much _____.
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sugar
( Phloem, not xylem, transports sugar.)
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Xerophytes minimize water loss by _____.
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using the CAM pathway
( CAM plants obtain CO2 through their stomata at night, thus conserving water.)
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The solute most abundant in phloem sap is _____.
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sugar
( Phloem transports sugar from a sugar source to a sugar sink.)
