Photosynthesis ceases when leaves wilt, mainly because
a. The chlorophyll in wilting leaves is degraded.
b. Accumulation of CO₂ in the leaf inhibits enzymes.
c. Stomata close, preventing CO₂ from entering the leaf.
d. Photolysis, the water-splitting step of photosynthesis, cannot occur when there is a water deficiency.

Compared with a cell with few aquaporin proteins in its membrane, a cell containing many aquaporin proteins will

a. Have a faster rate of osmosis

b. Have a lower water potential

c. Have a higher water potential

d. Accumulate water by active transport

What would enhance water uptake by a plant cell?

a. Decreasing the Ψ of the surrounding solution

b. Positive pressure on the surrounding solution

c. The loss of solutes from the cell

d. Increasing the Ψ of the cytoplasm

A plant cell with a Ψ_S of −0.65MPa maintains a constant volume when bathed in a solution that has a Ψ_S of −0.30MPa and is in an open container. The cell has a

a. Ψ_P of +0.65MPa

b. Ψ of −0.65MPa

c. Ψ_P of +0.35MPa

d. Ψ_P of 0 MPa

Which structure or compartment is part of the symplast?

a. The interior of a vessel element

b. The interior of a sieve tube

c. The cell wall of a mesophyll cell

d. An extracellular air space

Which of the following is an adaptation that enhances the uptake of water and minerals by roots?

a. Mycorrhizae

b. Pumping through plasmodesmata

c. Active uptake by vessel elements

d. Rhythmic contractions by cells in the root cortex

Movement of phloem sap from a source to a sink

a. Occurs through the apoplast of sieve-tube elements

b. Depends ultimately on the activity of proton pumps

c. Depends on tension, or negative pressure potential

d. Results mainly from diffusion