front 1 1) Given that early land plants most likely share a common ancestor
with green algae, the earliest land plants were most likely
________. C) vascular plants with well-defined root systems D) plants with well-developed leaves | back 1 A |
front 2 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? B) a tropical rain forest | back 2 B |
front 3 3) Phloem sap can flow ________. D) both ways between production and storage sites | back 3 D |
front 4 4) Why do most angiosperms have alternate phyllotaxy, with leaf
emergence at an angle of 137.5° compared to leaves above and
below? C) to reduce shading of lower leaves | back 4 D |
front 5 5) A plant developed a mineral deficiency after being treated with a
fungicide. What is the most probable cause of the deficiency? C) Active transport of minerals was inhibited. | back 5 B |
front 6 6) Which one of the following does not correctly match the form with its function? A) stem—water and minerals are transported upward D) cork cambium—increase in stem thickness | back 6 D |
front 7 7) The leaf area index is the ratio of the ________. | back 7 A |
front 8 8) Which one of the following played a critical role in the
successful colonization of land by plants? C) mycorrhizae | back 8 C |
front 9 9) Which structure or compartment is separate from the apoplastic route? A) the lumen of a xylem vessel D) the cell wall of a root hair | back 9 B |
front 10 10) The apoplast in plant tissues consists of ________. D) cell walls, plasma membrane, and cytosol | back 10 B |
front 11 11) Active transport of amino acids in plants at the cellular level requires ________. A) NADP and channel proteins D) ATP, transport proteins, and a proton gradient | back 11 D |
front 12 12) The physical property that predicts the direction of water flow is referred as ________. A) potassium pump D) sodium pump | back 12 B |
front 13 13) What is the function of proton pumps localized in the plant plasma membrane? A) to transfer phosphorus groups from ATP to proteins D) to create a membrane potential | back 13 D |
front 14 14) Which of following ions play the primary role in basic transport processes in plant cells? A) H+ D) Ca+2 | back 14 A |
front 15 15) Which of the following would be least likely to affect osmosis in plants? A) a difference in solute concentrations D) a difference in water potential | back 15 B |
front 16 16) The movement of water across biological membranes can best be predicted by ________. A) prevailing weather conditions D) water potentials | back 16 D |
front 17 17) 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. C) The cell walls would rupture, killing the cells. D) Solutes would move out of the cells. | back 17 A |
front 18 18) Solute potential in a cell is also called ________. A) water potential D) pressure potential | back 18 B |
front 19 19) 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 C) be in both directions, and the concentration of water would remain equal D) be impossible to determine from the values given here | back 19 A |
front 20 20) In the transmembrane route for transport within plant tissue,
________. | back 20 A |
front 21 21) 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 ________. 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 | back 21 C |
front 22 22) How does a flaccid cell differ from a turgid cell? A) A flaccid cell has higher pressure potential. D) A flaccid cell has lower solute potential. | back 22 B |
front 23 23) The protoplast consists of ________. | back 23 D |
front 24 24) Compared to a cell with few aquaporins in its membrane, a cell
containing many aquaporins will ________. C) have a higher water potential | back 24 A |
front 25 25) If you place flaccid plant cells in pure water, water ________
into cell because it has ________. C) enter the cell; solutes and high water potential | back 25 B |
front 26 26) If ΨP = 0.3 MPa and ΨS = -0.45 MPa, the resulting Ψ is ________.
A) +0.75 MPa D) +0.15 MPa | back 26 C |
front 27 27) Which of the following are important components of the long-distance transport process in plants?
A) II, III, IV, and V | back 27 C |
front 28 28) 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 C) be in both directions and the concentrations would remain equal D) occur only as ATP was hydrolyzed in the tissue | back 28 A |
front 29 29) Loss of water from the aerial parts of plants is called ________. A) dehydration D) transpiration | back 29 D |
front 30 30) Which of the following contribute to the surface area available for water absorption from the soil by a plant root system? I) root hairs A) II and III | back 30 B |
front 31 31) What is the overall charge on the cytoplasmic side of a plant cell plasma membrane? A) positive | back 31 B |
front 32 32) 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? C) the endodermis | back 32 C |
front 33 33) Bulk flow is much faster than diffusion or active transport. Peak
velocities in the transport of xylem sap can range from ________ for
trees with wide vessel elements. C) 5-10 m/hr | back 33 B |
front 34 34) In plant roots, the Casparian strip ________. | back 34 D |
front 35 35) Which of the following observations provides the strongest
evidence against root pressure being the principal mechanism of water
transport in the xylem? 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. | back 35 C |
front 36 36) One is most likely to see guttation in small plants when the ________. A) transpiration rates are high D) roots are not absorbing minerals from the soil | back 36 B |
front 37 37) Most of the water taken up by a plant is ________. A) used as a solvent D) used to keep cells turgid | back 37 C |
front 38 38) Transpiration in plants requires ________.
A) I, III, IV, and V | back 38 C |
front 39 39) During the nighttime, due to lack of transpiration, the water
potential within the vascular cylinder ________. C) lowers due to loss of minerals | back 39 A |
front 40 40) What is the main force by which most of the water within xylem
vessels moves toward the top of a tree? C) the force of root pressure | back 40 B |
front 41 41) Water potential is generally most negative in which of the following parts of a plant? A) mesophyll cells of the leaf D) cells of the root cortex | back 41 A |
front 42 42) Formation of the curved upper surface, such as occurs in a tube filled with water, is an important factor in plant water movement. A curved upper surface is created by ________. A) the upward pull of gravity on the water column in the
tube C) the water molecules being pulled upward by adhesion to the
air | back 42 D |
front 43 43) Which one of the following ions plays a critical role in the opening and closing of stomata? A) H+ D) Ca+2 | back 43 C |
front 44 44) Which of the following primarily enters a plant somewhere other than through the roots? A) carbon dioxide D) water | back 44 A |
front 45 45) 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 D) movement of K+ from the guard cells | back 45 A |
front 46 46) The high surface-to-volume ratio in leaves aids in ________. A)
more light absorption D) transpiration | back 46 C |
front 47 47) 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? C) a warm, humid day | back 47 B |
front 48 48) Photosynthesis ceases when leaves wilt, mainly because ________. A) the chlorophyll in wilting leaves is degraded D) accumulation of carbon dioxide in the leaf inhibits enzymes | back 48 C |
front 49 49) 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 ________. C) evaporative cooling and increased turgor | back 49 D |
front 50 50) Which of the following experimental procedures would most likely
reduce transpiration while allowing the normal growth of a
plant? C) putting the plant in drier soil | back 50 B |
front 51 51) 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? C) The leaves would become more turgid. | back 51 A |
front 52 52) What is the advantage of having small, needlelike leaves? A) increased transpiration rate D) decreased efficiency of light capture | back 52 B |
front 53 53) The plant hormone ________ causes stomatal closures in drought stress conditions. A) indole-3-acetic acid D) ethylene | back 53 C |
front 54 54) Plants adapted to arid environments are referred to as ________. A) mesophytes D) halophytes | back 54 B |
front 55 55) In xerophytes, ________ are referred to as crypts. A) stomata recessed in cavities D) lower epidermal cells | back 55 A |
front 56 56) Which of the following is a net sugar source for a deciduous angiosperm tree? A) new leaves in early spring D) roots in early autumn | back 56 C |
front 57 57) 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. A) 1, 2, 3, 4, 5 | back 57 B |
front 58 58) Water flows into the source end of a sieve tube because
________. B) water pressure outside the sieve tube forces in water | back 58 A |
front 59 59) Which of the following supports the finding that sugar
translocation in phloem is an active (energy-requiring)
process? B) Movement of water occurs from xylem to phloem and back
again. | back 59 A |
front 60 60) 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. D) A sink is the part of a plant where a particular solute is produced. | back 60 C |
front 61 61) In the pressure-flow mechanism, loading of sucrose from companion
cells to sieve-tube elements takes place through ________. C) sucrose-H+ symporters D) sucrose-H+ antiporters | back 61 A |
front 62 62) Which of the following is a correct statement about sugar movement in phloem? A) Diffusion can account for the observed rates of
transport. D) Only phloem cells with nuclei can perform sugar movement. | back 62 B |
front 63 63) 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 ________. | back 63 D |
front 64 64) 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? B) cell membrane | back 64 D |
front 65 65) Plasmodesmata can change in number, and when dilated can provide
a passageway for ________. C) chloroplasts | back 65 A |
front 66 66) The symplastic route can transport ________. A) sugars, mRNA, and mitochondria D) viruses, sugars, and mRNA | back 66 D |
front 67 1) Which of the following is an adaptation that enhances the uptake
of water and minerals by roots? C) active uptake by vessel elements | back 67 A |
front 68 2) Which structure or compartment is part of the symplast? A) the interior of a vessel element D) an extracellular air space | back 68 B |
front 69 3) 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. | back 69 B |
front 70 4) Photosynthesis ceases when leaves wilt, mainly because A) the chlorophyll in wilting leaves is degraded. D) photolysis, the water-splitting step of photosynthesis, cannot occur when there is a water deficiency. | back 70 C |
front 71 5) What would enhance water uptake by a plant cell? A) decreasing the Ψ of the surrounding solution D) increasing the Ψ of the cytoplasm | back 71 B |
front 72 6) A plant cell with a ΨS of -0.65 MPa maintains a constant volume
when bathed in a solution that has a ΨS of -0.30 MPa and is in an open
container. The cell has a C) ΨP of +0.35 MPa. D) ΨP of 0 MPa. | back 72 C |
front 73 7) Compared with a cell with few aquaporin proteins in its membrane,
a cell containing many aquaporin proteins will C) have a higher water potential. | back 73 A |
front 74 8) Which of the following would tend to increase transpiration? A)
spiny leaves D) higher stomatal density | back 74 D |