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Campbell Biology, 10e (Reece)
Chapter 36 Resource Acquisition and Transport in Vascular Plants
1) Given that early land plants most likely share a common ancestor with green algae, the earliest
land plants were most likely _____.
A) nonvascular plants that grew leafless, photosynthetic shoots
B) species that did not exhibit alternation of generations
C) vascular plants with well-defined root systems
D) plants with well-developed leaves
2) A fellow student brought in a leaf to be examined. The leaf was dark green, thin, had stoma 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 large, still pond
B) a tropical rain forest
C) an oasis within a grassland
D) the floor of a deciduous forest
3) Why do most angiosperms have alternate phyllotaxy, with leaf emergence at an angle of
137.5° compared to leaves above and below?
A) To allow maximum exposure to light
B) To promote a leaf area index above 8
C) To reduce shading of lower leaves
D) To allow maximum exposure to light and to reduce shading of lower leaves
4) A plant developed a mineral deficiency after being treated with a fungicide. What is the most
probable cause of the deficiency?
A) Mineral receptor proteins in the plant membrane were not functioning.
B) Mycorrhizal fungi were killed.
C) Active transport of minerals was inhibited.
D) The genes for the synthesis of transport proteins were destroyed.
5) Which structure or compartment is separate from the apoplastic route?
A) the lumen of a xylem vessel
B) the lumen of a sieve tube
C) the cell wall of a mesophyll cell
D) the cell wall of a root hair
6) The _____ is the most efficient route of water movement in plants, while the _____ is the
most select.
A) apoplast: symplast
B) apoplast: transmembrane
C) symplast apoplast
D) transmembrane: symplast
7) Active transport of amino acids in plants at the cellular level requires _____.
A) NADP and channel proteins
B) xylem membranes and channel proteins
C) sodium/potassium pumps and xylem membranes
D) ATP, transport proteins, and a proton gradient
8) What is the function of proton pumps localized in the plant plasma membrane?
A) to transfer phosphorus groups from ATP to proteins
B) to transfer metal ions across the plasma membrane
C) to transfer anions across the plasma membrane
D) to create a membrane potential
9) Which of the following would be LEAST likely to affect osmosis in plants?
A) a difference in solute concentrations
B) receptor proteins in the membrane
C) aquaporins
D) a difference in water potential
10) The movement of water across biological membranes can best be predicted by _____.
A) prevailing weather conditions
B) aquaporins
C) level of active transport
D) water potentials
11) If isolated plant cells with a water potential averaging -0.5 MPa are placed into a solution
with a water potential of -0.3 MPa, which of the following would be the most likely outcome?
A) The pressure potential of the cells would increase.
B) Water would move out of the cells.
C) The cell walls would rupture, killing the cells.
D) Solutes would move out of the cells.
12) The value for Ψ in root tissue was found to be -0.15 MPa. If you take the root tissue and
place it in a 0.1 M solution of sucrose (Ψ = -0.23 MPa), the net water flow would _____.
A) be from the tissue into the sucrose solution
B) be from the sucrose solution into the tissue
C) be in both directions and the concentration of water would remain equal
D) be impossible to determine from the values given here
13) When an animal cell is placed in a hypotonic solution and water enters the cell via osmosis,
the volume of the cell increases until it bursts. This does not happen to plant cells, because
_____.
A) they have large central vacuoles, which provide abundant space for storage of incoming water
B) they have cell walls, which prevent the entry of water by osmosis
C) they have cell walls, which provide pressure to counteract the pressure of the incoming water
D) certain gated channel proteins embedded in their plasma membranes open as osmotic pressure
decreases, allowing excess water to leave the cell
14) How does a flaccid cell differ from a turgid cell?
A) A flaccid cell has higher pressure potential.
B) A flaccid cell has lower pressure potential.
C) A flaccid cell has higher solute potential.
D) A flaccid cell has lower solute potential.
15) Compared to a cell with few aquaporins in its membrane, a cell containing many aquaporins
will _____.
A) have a faster rate of osmosis
B) have a lower water potential
C) have a higher water potential
D) have a faster rate of active transport
16) Which of the following statements about bulk flow are correct?
I) Bulk flow is driven primarily by pressure potential.
II) Bulk flow depends on a difference in pressure potential at the source and sink.
III) Bulk flow depends on the force of gravity on a column of water.
IV) Bulk flow may be the result of either positive or negative pressure potential.
A) I and III
B) II and III
C) I, II, and IV
D) I, II, III, and IV
17) 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) II, III, IV, and V
B) I, III, IV, and V
C) I, II, IV, and V
D) I, II, III, and V
18) Loss of water from the aerial parts of plants is called _____.
A) dehydration
B) respiration
C) gas exchange
D) transpiration
19) 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) II and III
B) I, III, and IV
C) I, II, and IV
D) I, II, III, and IV
20) What is the overall charge on the cytoplamsic side of a plant cell plasma membrane?
A) positive
B) negative
C) neutral
21) 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) a guard cell
B) the root epidermis
C) the endodermis
D) the root cortex
22) In plant roots, the Casparian strip _____.
A) aids in the uptake of nutrients
B) provides energy for the active transport of minerals into the stele from the cortex
C) ensures that all minerals are absorbed from the soil in equal amounts
D) ensures that all water and dissolved substances must pass through a cell membrane before
entering the stele
23) Which of the following observations provides the strongest evidence against root pressure
being the principal mechanism of water transport in the xylem?
A) Not all soils have high concentrations of ions.
B) Root pressure requires movement of water into the xylem from surrounding cells in the roots.
C) Over long distances, the force of root pressure is not enough to overcome the force of gravity.
D) There is no water potential gradient between roots and shoots.
24) One is most likely to see guttation in small plants when the _____.
A) transpiration rates are high
B) root pressure exceeds transpiration pull
C) the preceding evening was hot, windy, and dry
D) roots are not absorbing minerals from the soil
25) Most of the water taken up by a plant is _____.
A) used as a solvent
B) used as a hydrogen source in photosynthesis
C) lost during transpiration
D) used to keep cells turgid
26) 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 V
D) I, II, III, and IV
27) What is the main force by which most of the water within xylem vessels moves toward the
top of a tree?
A) active transport of ions into the stele
B) evaporation of water through stoma
C) the force of root pressure
D) osmosis in the root
28) Water potential is generally most negative in which of the following parts of a plant?
A) mesophyll cells of the leaf
B) xylem vessels in leaves
C) xylem vessels in roots
D) cells of the root cortex
29) As an undergraduate research assistant, your duties involve measuring water potential in
experimental soil-plant-atmosphere systems. Assume you make a series of measurements in a
system under normal daylight conditions, with stomata open and photosynthesis occurring.
Which of the following correctly depicts the trend your measurement data should follow if the
cohesion-tension mechanism is operating?
A) ψsoil < ψroots = ψleaves < ψatmosphere
B) ψatmosphere < ψleaves = ψroots < ψsoil
C) ψsoil < ψroots < ψleaves < ψatmosphere
D) ψatmosphere < ψleaves < ψroots < ψsoil
30) Formation of menisci, such as occurs in a tube filled with water, is an important factor in
plant water movement. A meniscus is created by _____.
A) the upward pull of gravity on the water column in the tube
B) downward pressure from the atmosphere on the topmost layer of water molecules
C) the water molecules being pulled upward by adhesion to the air
D) the topmost layer of water molecules being pulled downward by the hydrogen bonds to the
water molecules below
31) Which mechanism of water transport in xylem can contribute to recovery from cavitation?
A) cohesion-tension
B) capillarity
C) pressure flow
D) root pressure
32) Which of the following primarily enters a plant somewhere other than through the roots?
A) carbon dioxide
B) nitrogen
C) potassium
D) water
33) The opening of stomata is thought to involve _____.
A) an increase in the solute concentration of the guard cells
B) active transport of water out of the guard cells
C) decreased turgor pressure in guard cells
D) movement of K+ from the guard cells
34) Ignoring all other factors, what kind of day would result in the fastest delivery of water and
minerals to the leaves of an oak tree?
A) cool, dry day
B) very hot, dry, windy day
C) warm, humid day
D) cool, humid day
35) Photosynthesis ceases when leaves wilt, mainly because _____.
A) the chlorophyll in wilting leaves is degraded
B) flaccid mesophyll cells are incapable of photosynthesis
C) stomata close, preventing carbon dioxide from entering the leaf
D) accumulation of carbon dioxide in the leaf inhibits enzymes
36) The water lost during transpiration is a side effect of the plant's exchange of gases. However,
the plant derives some benefit from this water loss in the form of _____.
A) increased turgor and increased growth
B) mineral transport and increased growth
C) evaporative cooling and increased turgor
D) evaporative cooling and mineral transport
37) Which of the following experimental procedures would most likely reduce transpiration
while allowing the 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
38) Several tomato plants are growing in a small garden plot. If soil water potential were to drop
significantly on a hot, summer afternoon, which of the following would most likely occur?
A) Size of stomatal openings would decrease.
B) Transpiration would increase.
C) The leaves would become more turgid.
D) The uptake of carbon dioxide would be enhanced.
39) What is the advantage of having small, needlelike leaves?
A) increased transpiration rate
B) decreased transpiration rate
C) increased efficiency of light capture
D) decreased efficiency of light capture
40) Which of the following is a net sugar source for a deciduous angiosperm tree?
A) new leaves in early spring
B) fruits in summer
C) roots in early spring
D) roots in early autumn
41) Phloem transport is described as being from source to sink. Which of the following would
most accurately complete this statement about phloem transport as applied to most plants in the
late spring?
Phloem transports ________ from the ________ source to the ________ sink.
A) amino acids; root; mycorrhizae
B) sugars; leaf; apical meristem
C) proteins; root; leaf
D) sugars; woody stem; root
42) Arrange the following five events in an order that explains the mass flow of materials in the
phloem.
1. Water diffuses into the sieve tubes.
2. Leaf cells produce sugar by photosynthesis.
3. Solutes are actively transported into sieve tubes.
4. Sugar is transported from cell to cell in the leaf.
5. Sugar moves down the stem.
A) 1, 2, 3, 4, 5
B) 2, 4, 3, 1, 5
C) 4, 2, 1, 3, 5
D) 2, 4, 1, 3, 5
43) Water flows into the source end of a sieve tube because _____.
A) sucrose has been actively transported into the sieve tube, making it hypertonic
B) water pressure outside the sieve tube forces in water
C) the companion cell of a sieve tube actively pumps in water
D) sucrose has been transported out of the sieve tube by active transport
44) Which of the following supports the finding that sugar translocation in phloem is an active
(energy-requiring) process?
A) Sucrose occurs in higher concentrations in companion cells than in the mesophyll cells where
it is produced.
B) Movement of water occurs from xylem to phloem and back again.
C) Strong pH differences exist between the cytoplasm of the companion cell and the mesophyll
cell.
D) ATPases are abundant in the plasma membranes of the mesophyll cells.
45) Which one of the following statements about transport of nutrients in phloem is correct?
A) Solute particles are actively transported from phloem at the source.
B) Companion cells control the rate and direction of movement of phloem sap.
C) Differences in osmotic concentration at the source and sink cause a hydrostatic pressure
gradient to be formed.
D) A sink is the part of a plant where a particular solute is produced.
46) In the pressure-flow mechanism, loading of sucrose from companion cells to sieve-tube
elements takes place through _____.
A) plasmodesmata
B) facilitated diffusion
C) sucrose-H+ symporters
D) sucrose-H+ antiporters
47) Which of the following is a correct statement about sugar movement in phloem?
A) Diffusion can account for the observed rates of transport.
B) Movement can occur both upward and downward in the plant.
C) Sugar is translocated from sinks to sources.
D) Only phloem cells with nuclei can perform sugar movement.
48) Plants do not have a circulatory system like that of some animals. If a water molecule in a
plant did "circulate" (that is, go from one point in a plant to another and back in the same day), it
would require the activity of _____.
A) only the xylem
B) only the phloem
C) only the endodermis
D) both the xylem and the phloem
49) As an undergraduate research assistant, you are assisting with a radioisotope tracer
experiment. You expose a mature leaf on one side of the lower shoot of a sugar beet plant to
14CO2 and then track the movement of the 14C atoms by radiography. Where are you LEAST
likely to detect 14C?
A) the treated leaf
B) the shoot apical meristem
C) the roots
D) a mature upper leaf on the opposite side of the plant from the treated leaf
50) Which of the following is a similarity between xylem and phloem transport?
A) Many cells in both tissues have sieve plates.
B) Expenditure of energy from ATP is required.
C) Transpiration is required for both processes.
D) Bulk flow of water is involved.
51) Some botanists argue that the entire plant should be considered as a single unit rather than a
composite of many individual cells. Which of the following cellular structures best supports this
view?
A) cell wall
B) cell membrane
C) vacuole
D) plasmodesmata
52) Plasmodesmata can change in number, and when dilated can provide a passageway for
_____.
A) macromolecules such as ribonucleic acid (RNA) and proteins
B) ribosomes
C) chloroplasts
D) mitochondria
53) The symplastic route can transport _____.
A) sugars, mRNA, and mitochondria
B) mRNA, mitochondria, and proteins
C) mitochondria, mRNA, and viruses
D) viruses, sugars, and mRNA
