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| 1 | |
Loss of turgor pressure in guard cells causes an uptake of |
| | A) | K+. |
| | B) | H+. |
| | C) | ATP. |
| | D) | CO2. |
| | E) | Na+. |
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| 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 |
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| 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. |
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| 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. |
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| 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. |
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| 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 |
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| 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. |
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| 8 | |
Water moves from low water potential to higher water potential. |
| | A) | True |
| | B) | False |
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| 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. |
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| 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. |
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| 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. |
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| 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 |
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| 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. |
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| 14 | |
Movement across a plant's cell wall requires |
| | A) | solute pressure. |
| | B) | auxin. |
| | C) | osmotic pressure. |
| | D) | pressure potential. |
| | E) | physical pressure. |
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| 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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