AP Biology Self Quiz Chapter 32: Transport in Plants

1. Which of the following is true concerning the water potential of a plant cell?
a. It is higher than that of air.
b. It is equal to 0 when the cell is in pure water and is turgid.
c. It is equal to 0.23 MPa.
d. It becomes higher when K + ions are actively moved into the cell.
e. It becomes lower after the uptake of water by osmosis.

2. If the guard cells and surrounding epidermal cells in a plant are deficient in potassium ions, all of the following would occur EXCEPT
a. photosynthesis would decrease.
b. roots would take up less water.
c. phloem transport rates would decrease.
d. leaf temperatures would decrease.
e. wilting would become more likely.

3. All of the following are factors in the movement of water through a terrestrial plant EXCEPT
a. hydrogen bonds linking water molecules.
b. the influence of gibberellin on cell expansion.
c. capillary action due to adhesion of water molecules for walls of thin tubes.
d. root pressure.
e. evaporation of water from the leaves.

4. Which of the following experimental procedures would significantly reduce transpiration while allowing 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

5. Active transport would be least important in the normal functioning of which of the following plant tissue types?
a. leaf epidermis
b. stem xylem
c. root endodermis
d. leaf mesophyll
e. root phloem

6. Assume a particular chemical interferes with the establishment and maintenance of proton gradients across the membranes of plant cells. All of the following processes would be greatly affected by this chemical EXCEPT
a. photosynthesis.
b. phloem loading.
c. xylem transport.
d. cellular respiration.
e. stomatal opening.

7. 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. Casparian strip
b. guard cell
c. root epidermis
d. endodermis
e. root cortex

8. Plants do not have a circulatory system like that of some animals.If a given water molecule did "circulate" (that is, go from one point in a plant to another and back) it would require the activity of
a. only the xylem.
b. only the phloem.
c. only the endodermis.
d. both xylem and endodermis.
e. both xylem and phloem.

9. Phloem transport of sucrose can be described as going from "source to sink." Which of the following would not normally function as a sink?
a. growing leaf
b. growing root
c. storage organ in summer
d. mature leaf
e. shoot tip

10. The water lost during transpiration is an unfortunate side effect of the plant's need to exchange gases. However, the plant derives some benefit from this water loss in the form of
a. evaporative cooling.
b. mineral transport.
c. increased turgor.
d. evaporative cooling and mineral transport.
e. evaporative cooling, mineral transport, and increased turgor.

11. Photosynthesis begins to decline when leaves wilt because
a. flaccid cells are incapable of photosynthesis.
b. CO 2 accumulates in the leaves and inhibits photosynthesis.
c. there is insufficient water for photolysis during light reactions.
d. stomata close, preventing CO 2 entry into the leaf.
e. the chlorophyll of flaccid cells cannot absorb light.

12. Ignoring all other factors, what kind of day would result in the fastest delivery of water and minerals to the leaves of a tree?
a. cool, dry day
b. warm, dry day
c. warm, humid day
d. cool, humid day
e. very hot, dry, windy day

13. In the pressure-flow hypothesis of translocation, from what does the pressure result?
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

14. Transpiration in plants requires all of the following EXCEPT
a. adhesion of water molecules to cellulose.
b. cohesion between water molecules.
c. evaporation of water molecules.
d. active transport through xylem cells.
e. transport through xylem cells.

15. Root hairs are most important to a plant because they
a. anchor a plant into the soil.
b. store starches.
c. increase the surface area for absorption.
d. provide a habitat for nitrogen-fixing bacteria.
e. contain xylem tissue.