Chapter 36 Questions Flashcards
A fellow student brought in a leaf to be examined. The leaf was dark green, thin, had stomata on the lower surface only, and had a total surface area of ten square meters. Where is the most likely environment where this leaf was growing?
a. a tropical rain forest
b. an oasis within a grassland
c. a large, still pond
d. the floor of a deciduous forest
a. a tropical rain forest
Why do most angiosperms have alternate phyllotaxy, with leaf emergence at an angle of 137.5 degrees compared to leaves above and below?
a. to allow maximum exposure to light and to reduce shading of lower leaves
b. to allow maximum exposure to light
c. to promote a leaf area index above 8
d. to reduce shading of lower leaves
a. to allow maximum exposure to light and to reduce shading of lower leaves
A plant developed a mineral deficiency after being treated with a fungicide. What is the most probable cause of the deficiency?
a. Active transport of minerals was inhibited.
b. Mycorrhizal fungi were killed.
c. The genes for the synthesis of transport proteins were destroyed.
d. Mineral receptor proteins in the plant membrane were not functioning.
b. Mycorrhizal fungi were killed.
The apoplast in plant tissues consists of ___.
a. cell walls, plasma membrane, and cytosol
b. cell walls, extracellular spaces, and vessel elements
c. cell walls, extracellular spaces, and plasmodesmata
d. vessel elements, plasmodesmata, and extracellular spaces
b. cell walls, extracellular spaces, and vessel elements
Which of the following ions play the primary role in basic transport processes in plant cells?
a. K+
b. H+
c. Ca+2
d. Na+
b. H+
Which of the following would be least likely to affect osmosis in plants?
a. receptor proteins in the membrane
b. aquaporins
c. a difference in water potential
d. a difference in solute concentrations
a. receptor proteins in the membrane
How does a flaccid cell differ from a turgid cell?
a. A flaccid cell has higher pressure potential.
b. A flaccid cell has higher solute potential.
c. A flaccid cell has lower solute potential.
d. A flaccid cell has lower pressure potential.
d. A flaccid cell has lower pressure potential.
Compared to a cell with few aquaporins in its membrane, a cell containing many aquaporins will ___.
a. have a faster rate of active transport
b. have a lower water potential
c. have a higher water potential
d. have a faster rate of osmosis
d. have a faster rate of osmosis
Which of the following are important components of the long-distance transport process in plants? I. the cohesion of water molecules II. a negative water potential III. the root parenchyma IV. the active transport of solutes V. bulk flow from source to sink a. I, II, IV, and V b. I, III, IV, and V c. I, II, III, and V d. II, III, IV, and V
a. I, II, IV, and V
Which of the following contribute to the surface area available for water absorption from the soil by a plant root system? I. root hairs II. endodermis III. mycorrhizae IV. fibrous arrangement of the roots a. I, II, III, and IV b. I, III, and IV c. I, II, and IV d. II and III
b. I, III, and IV
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 more. This living cell would be a part of which structure?
a. the roof cortex
b. the endodermis
c. a guard cell
d. the root epidermis
b. the endodermis
In plant roots, the Casparian strip ___.
a. aids in the uptake of nutrients
b. ensures that all water and dissolved substances must pass through a cell membrane before entering the stele
c. provides energy for the active transport of minerals into the stele from the cortex
d. ensures that all minerals are absorbed from the soil in equal amounts
b. ensures that all water and dissolved substances must pass through a cell membrane before entering the stele
Transpiration in plants requires \_\_\_. I. adhesion of water molecules to cellulose II. cohesion between water molecules III. evaporation of water molecules IV. active transport through xylem cells V. transport through tracheids a. I, III, IV, and V b. I, II, IV, and V c. I, II, III, and IV d. I, II, III, and V
d. I, II, III, and V
Water potential is generally most negative in which of the following parts of a plant
a. xylem vessels in roots
b. xylem vessels in leaves
c. mesophyll cells of the land
d. cells of the root cortex
c. mesophyll cells of the land
Which one of the following ions plays a critical role in the opening and closing of stomata?
a. Na+
b. K+
c. H+
d. Ca+2
b. K+
Which of the following primarily enters a plant somewhere other than through the roots?
a. carbon dioxide
b. potassium
c. water
d. nitrogen
a. carbon dioxide
Ignoring all other factors, what kind of day would result in the fastest delivery of water and minerals to the laves of an oak tree?
a. a cool, dry day
b. a warm, humid day
c. a very hot, dry, windy day
d. a cool, humid day
c. a very hot, dry, windy day
Plants adapted to arid environments are referred to as ___.
a. xerophytes
b. halophytes
c. psilophytes
d. mesophytes
a. xerophytes
Arrange the following five events in an order that explains the mass flow of materials in the phloem.
- Water diffuses into the sieve tubes.
- Leaf cells produce sugar by photosynthesis.
- Solutes are actively transported into sieve tubes
- Sugar is transported from the cell to cell in the leaf.
- Sugar moves down the stem.
a. 2, 4, 3, 1, 5
b. 1, 2, 3, 4, 5
c. 4, 2, 1, 3, 5
d. 2, 4, 1, 3, 5
a. 2, 4, 3, 1, 5
Which of the following statements about the movement of water and inorganic nutrients in plants is true?
a. Water and nutrients move from the roots to the leavesvia the stem or trunk.
b. Water and nutrients move from the leaves to the roots via the stem or trunk.
c. Water and nutrients can move either from leaves to roots or from roots to leaves via the stem or trunk.
d. Water and nutrients are taken up by the roots and move symplastically by active transport to leaves.
e. Water and nutrients are pumped from the roots to the leaves via a proton pump.
a. Water and nutrients move from the roots to the leavesvia the stem or trunk.
About ____% of a plant’s water escapes through the stomata, although the stomata account for just ____% of the external leaf surface.
a. 75; 10
b. 75; 1–2
c. 95; 10
d. 95; 1–2
d. 95; 1–2
The basis of the pull generated by transpiration in the xylem is ____.
a. positive root pressure from differences in solute potential between soil and root.
b. positive pressure generated by the shrinking in diameter of the trunk or stem.
c. negative pressure at the air-water interface in the leaf.
d. pressure created by proton pumping of stomatal guard cells.
e. adhesion of water molecules to xylem cell walls.
c. negative pressure at the air-water interface in the leaf.
Which reflects the correct relationship of water potentials for a typical tree on a sunny day?
a. leaf Ψ < trunk Ψ < soil Ψ
b. outside air Ψ > leaf c. mesophyll Ψ < root Ψ
c. leaf Ψ > trunk Ψ > soil Ψ
d. soil Ψ < root Ψ > leaf Ψ
e. none of the above
a. leaf Ψ < trunk Ψ < soil Ψ
Water can follow two pathways in plants, apoplastic and symplastic. How do these pathways differ?
a. The apoplastic route is for water; the symplastic route is for nutrients.
b. The apoplastic route is entirely external to cell membranes; the symplastic route is inside of cells.
c. The apoplastic route is for nutrients; the symplastic route is for water.
d. The apoplastic route is used in phloem; the symplastic route is used in xylem.
b. The apoplastic route is entirely external to cell membranes; the symplastic route is inside of cells.
