Biology (Raven), 9th Edition

Chapter 38: Transport in Plants

Post-Test

1
Loss of turgor pressure in guard cells causes an uptake of
A)K+.
B)H+.
C)ATP.
D)CO2.
E)Na+.
2
What chemical property is most necessary for water to move from roots to the shoot of a plant?
A)Hydrogen bonding between water molecules
B)Capillary action within tracheids of plants
C)Active transport of solutes from the soil into root cells (such as root hairs)
D)Proton pumps drawing water into cells through osmosis
E)Opening and closing of stomata
3
The Casparian strip is a hydrophobic barrier that allows discrimination of which particles may pass through the
A)epidermis.
B)cortex.
C)ground tissue.
D)xylem.
E)endodermis.
4
Guttation occurs as a result of
A)excessive heat on a leaf surface.
B)excessive light on a leaf surface.
C)root pressure.
D)active transport of water into leaf cells.
E)active transport of solute into vessels.
5
The reason guard cells bend open is because water moves in through osmosis. This is because
A)potassium accumulates within the cell, rendering it hypertonic.
B)chloride enters the cell, making it hypertonic.
C)proton pumps create membrane potential, which drives accumulation of osmotically active substances.
D)All of the above affect guard cell behavior.
E)none of these are important in water movement.
6
What structure on pneumatophores (a modified root) allows mangrove plants to survive in flooded regions by facilitating gas exchange?
A)Stomata
B)Halophytes
C)Parenchyma
D)Lenticels
E)Collenchyma
7
How might a "sink" increase the amount of bulk flow of material towards itself through the phloem?
A)It will actively unload material across the living membrane of a phloem cell, causing more to flow in to take its place.
B)It will pump in hydrogen and sugar together in order to create a hypotonic situation within phloem cells next to it.
C)By quickly breaking down sugars in its vicinity, the "sink" will create a gradient down which new material will flow and accumulate.
D)The sink will decrease its turgor pressure, causing water potential to move new, energy rich material to take its place.
E)Stomata in the sink will open and draw in new, fresh photosynthate to take its place.
8
Water moves from low water potential to higher water potential.
A)True
B)False
9
Cells that travel the simplest route exclusively move from cell-to-cell via
A)membrane proteins.
B)phospholipid channels.
C)vacuole portals.
D)cell wall diffusion.
E)plasmodesmata.
10
In xylem elements, as the diameter of a tracheid decreases, the tensile strength of the fluid column within it
A)increases.
B)decreases.
C)approaches zero.
D)approaches infinity.
E)becomes more likely to cavitate.
11
Transpiration rate is regulated by the activity of
A)proton pumps.
B)xylem diameter sphincters.
C)phloem diameter sphincters.
D)cell wall expansion
E)guard cell dilation.
12
What is the most significant problem faced by most plants during flooding?
A)Deprivation from sunlight
B)Leaching of solutes into the environment
C)Erosion of the root system
D)Oxygen deprivation
E)Excessive transpiration
13
Which of the following best describes the difference between phloem transport and xylem transport?
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.
14
Movement across a plant's cell wall requires
A)solute pressure.
B)auxin.
C)osmotic pressure.
D)pressure potential.
E)physical pressure.
15
Water moves from the soil into the plant if the water potential of the root is _____________
A)less than that of the soil.
B)continuously changing.
C)greater than that of the soil.
D)equal to the water potential of the soil.
E)greater than that of the leaves.
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