Chapter 32

1. Roots take up K⁺ ions
a. with both solute and electrochemical gradients.
b. with the solute gradient and against the electrochemical gradient.
c. against the solute gradient and with the electrochemical gradient.
d. against both solute and electrochemical gradients.
e.independently of any gradients.

2. The use of transmembrane proton gradients in solute transport across membranes is called
a. cotransport.
b. chemiosmosis.
c. bulk flow.
d. selective channeling.
e. osmosis.

3. A root cell's ability to take up water is determined by _ and measured in _ .
a. the ion concentration/pH
b. the electron concentration/eV
c. the water potential/MPa
d. osmosis/d
e. membrane potential/eV

4. In a water hose that is divided by a selectively permeable membrane, physical pressure and the addition of solutes to one half will
a. both decrease its water potential.
b. both increase its water potential.
c. increase and decrease its water potential, respectively.
d. decrease and increase its water potential, respectively.
e. have no effect on its water potential.

5. You have lettuce in your refrigerator that is one day old. What could you do to increase its crispiness slightly?
a. Soak it in saltwater.
b. Soak it in distilled water.
c. Soak it in sugar water.
d. Dry it off with a towel.
e. Press it slightly.

6. Ion pumps in plant cells generally build the following relative H₊ concentrations in the vacuole, cytoplasm, and their immediate environment:
a. low/high/low
b. low/low/high
c. high/low/high
d. high/high/low
e. low/low/low

7. The symplast is
a. the joined cytoplasms of plant tissue cells.
b. the area between neighboring plant tissue cells.
c. the pores between plant tissue cells.
d. the joined cell walls of plant tissue cells.
e. the area between the tonoplast and the plasma membrane in a plant cell.

8. Bulk flow is
a. passive flow of water that contains solutes.
b. water flowing in separate waves.
c. flow of water and solutes driven by osmosis.
d. flow of water and solutes driven by pressure.
e. water flow through the apoplast.

10. The Casparian strip, made of _ , ensures that _ .
a. lignin/water does not leak out of the stele
b. lignin/minerals and water pass through the apoplast
c. suberin/minerals and water pass through the apoplast
d. suberin/minerals and water pass through the plasma membranes
e. suberin/minerals and water pass through the tracheids

10. During the passage from the soil to the xylem, a mineral may follow which route?
a. apoplastic/apoplastic/symplastic
b. apoplastic/symplastic/apoplastic
c. symplastic/apoplastic/symplastic
d. symplastic/apoplastic/apoplastic
e. all of the above

11. Hydathodes are used
a. during transpiration.
b. during osmotic water uptake at night.
c. during guttation.
d. for the generation of root pressure.
e. for the transpiration pull.

12. The meniscus in a leaf
a. lies at the end of the petiole and allows leaf movements.
b. connects the water in the stomata to the water in the xylem.
c. is the convex water surface in the stomata.
d. is the outer membrane of the vacuole.
e. is the concave water surface in the stomata.

13. A wilted looking plant probably did not get sufficient _ over the day.
a. water
b. water and minerals
c. water and CO₂
d. water, minerals, and CO₂
e. water, minerals, CO₂, and O₂

14. It is reported that tree trunks change in diameter slightly in response to the water potential. Can you use the circumference of the tree in your front lawn as a reliable thermometer (assuming you know how much it grows)?
a. Yes, the water potential changes linearly with air temperature
b. Yes, as long as you calibrate the circumference of the tree with the air temperature.
c. No, because the relationship between water potential and air temperature is not linear.
d. No, because the water potential also depends on humidity in the air.
e. No, because the water potential is generated by root pressure in the morning and by transpiration in the afternoon.

15. Commonly, a plant looses _ g of water for each g of fixed CO₂.
a. 2
b. 20
c. 200
d. 400
e. 600

16. The opening of the stomata is controlled by
a. K₊ fluxes in and out of the guard-cell tonoplast.
b. the evaporation from the guard cells.
c. the Cl_- fluxes in and out of the guard cells.
d. the angle of the meniscus.
e. the water in the guard cell walls.

17. You measure the gases in a green house. Your result show that CO₂ concentration goes down at night and remains relatively constant during daytime. You conclude that
a. you are measuring common photosynthetic activity.
b. your plants may not have enough water.
c. you have mostly CAM plants in your greenhouse.
d. the blue light is filtered out by the green house glass.
e. a lot of plant material is decomposed over night.

18. Vermont maple syrup consists mostly of fluid that was
a. transported through phloem.
b. transported through xylem.
c. transported through stomata.
d. transported through roots.
e. stored in fruits.

19. Transfer cells are modified
a. sieve-tube members.
b. tracheids.
c. vessel elements.
d. companion cells.
e. hydathodes.

20. The selection of minerals that are taken up by roots takes place
a. in the cell walls.
b. in the root hairs.
c. in the symplast.
d. in the plasma membranes.
e. in the tonoplast.