Biology, Eighth Edition (Raven)

Chapter 38: Transport in Plants

Pre Test

True or false: Water moves from low water potential to higher water potential. (p. 758)
Cells that travel the symplast route exclusively move from cell-to-cell via (p. 763)
A)membrane proteins.
B)phospholipid channels.
C)vacuole portals.
D)cell wall diffusion.
In xylem elements, as the diameter of a tracheid decreases, the tensile strength of the fluid column within it (p. 765)
C)approaches zero.
D)approaches infinity.
E)becomes more likely to cavitate.
Transpiration rate is regulated by the activity of (p. 765)
A)proton pumps.
B)xylem diameter sphincters.
C)phloem diameter sphincters.
D)cell wall expansion
E)guard cell dilation.
What is the most significant problem faced by most plants during flooding? (p. 768)
A)Deprivation from sunlight
B)Leaching of solutes into the environment
C)Erosion of the root system
D)Oxygen deprivation
E)Excessive transpiration
Which of the following best describes the difference between phloem transport and xylem transport? (p. 769)
A)Xylem transport requires active pumping at stomata. Phloem doesn't.
B)Phloem movement relies on the water column in plants and is solar powered. Xylem isn't.
C)Phloem carries fluid from the soil to the leaves, while xylem is the reverse.
D)Phloem can reverse direction, depending on the activity of the "source" and "sink" of its materials. Xylem is more unidirectional.
E)Xylem has soluble materials within it. Phloem contains insoluble ones.
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