Deck 29: Resource Acquisition, Nutrition, and Transport in Vascular Plants

Question 1

The movement of water across biological membranes can best be predicted by

A) negative charges in the cell wall.
B) prevailing weather conditions.
C) aquaporins.
D) level of active transport.
E) water potentials.

Answer 1

E

Question 2

All of the following have an effect on water potential (Ψ) in plants except

A) physical pressure.
B) water-attracting matrices.
C) dissolved solutes.
D) osmosis.
E) DNA structure.

Answer 2

E

Question 3

Which of the following statements is false about bulk flow?

A) It is driven primarily by pressure potential.
B) It is more effective than diffusion over distances greater than 100 μm.
C) It depends on a difference in pressure potential at the source and sink.
D) It depends on the force of gravity on a column of water.
E) It may be the result of either positive or negative pressure potential.

Answer 3

D

Question 4

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.
E) be flaccid.

Question 5

Plants do not have a circulatory system like that of some animals. If a water molecule 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 endodermis.
E) both the xylem and the phloem.

Question 6

Which of the following statements about xylem is incorrect?

A) It conducts material from root tips to leaves.
B) The conducting cells are part of the apoplast.
C) It transports mainly sugars and amino acids.
D) It typically has a lower water potential than is found in soil.
E) No energy input is required for transport.

Question 7

Plasmodesmata can change in number, and when dilated can provide a passageway for

A) macromolecules such as RNA and proteins.
B) ribosomes.
C) chloroplasts.
D) mitochondria.
E) cytoskeletal components.

Question 8

The ancestors of land plants were aquatic algae. Which of the following is not an evolutionary adaptation to life on land?

A) C3 photosynthesis
B) a waxy cuticle
C) root hairs
D) xylem and phloem
E) guard cells

Question 9

Active transport involves all of the following except

A) diffusion of solute through the lipid bilayer of a membrane.
B) pumping of solutes across the membrane.
C) hydrolysis of ATP.
D) transport of solute against a concentration gradient.
E) specific transport proteins in the membrane.

Question 10

All of the following are plant adaptations to life on land except

A) tracheids and vessels.
B) root hairs.
C) cuticle.
D) the Calvin cycle of photosynthesis.
E) collenchyma.

Question 11

Which of the following is not a function of the plasma membrane proton pump?

A) hydrolyzes ATP
B) produces a proton gradient
C) generates a membrane potential
D) equalizes the charge on each side of a membrane
E) stores potential energy on one side of a membrane

Question 12

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 above the shallow fresh water in which they lived.
B) species that did not exhibit alternation of generations.
C) vascular plants with well-defined root systems.
D) plants with well-developed leaves.
E) species with a well-developed, thick cuticle.

Question 13

Which of the following statements about transport in plants is false?

A) Weak bonding between water molecules and the walls of xylem vessels or tracheids helps support the columns of water in the xylem.
B) Hydrogen bonding between water molecules, which results in the high cohesion of the water, is essential for the rise of water in tall trees.
C) Although some angiosperm plants develop considerable root pressure, this is not sufficient to raise water to the tops of tall trees.
D) Most plant physiologists now agree that the pull from the top of the plant resulting from transpiration is sufficient, when combined with the cohesion of water, to explain the rise of water in the xylem in even the tallest trees.
E) Gymnosperms can sometimes develop especially high root pressure, which may account for the rise of water in tall pine trees without transpiration pull.

Question 14

Which structure or compartment is not part of the plant's apoplast?

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 transfer cell
E) the cell wall of a root hair

Question 15

All of the following normally enter the plant through the roots except

A) carbon dioxide.
B) nitrogen.
C) potassium.
D) water.
E) calcium.

Question 16

Which of the following would be least likely to affect osmosis in plants?

A) proton pumps in the membrane
B) a difference in solute concentrations
C) receptor proteins in the membrane
D) aquaporins
E) a difference in water potential

Question 17

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 concentrations would remain equal.
D) occur only as ATP was hydrolyzed in the tissue.
E) be impossible to determine from the values given here.

Question 18

Active transport of various materials in plants at the cellular level requires all of the following except

A) a proton gradient.
B) ATP.
C) a membrane potential.
D) transport proteins
E) xylem membranes.

Question 19

An open beaker of pure water has a water potential (Ψ) of

A) -0.23 MPa.
B) +0.23 MPa.
C) +0.07 MPa.
D) -0.0000001 MPa.
E) 0.0 (zero).

Question 20

If ΨP = 0.3 MPa and ΨS = -0.45 MPa, the resulting Ψ is

A) +0.75 MPa.
B) -0.75 MPa.
C) -0.15 MPa.
D) +0.15 MPa.
E) -0.42 MPa.

Question 21

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
E) root hairs

Question 22

Active transport would be least important in the normal functioning of which of the following plant tissue types?

A) leaf transfer cells
B) stem tracheary elements
C) root endodermal cells
D) leaf mesophyll cells
E) root sieve-tube elements

Question 23

Which of the following has the lowest (most negative) water potential?

A) root cortical cells
B) root xylem
C) trunk xylem
D) leaf cell walls
E) leaf air spaces

Question 24

What is the driving force for the movement of solutes in the phloem of plants?

A) gravity
B) a difference in water potential (Ψ) between the source and the sink
C) root pressure
D) transpiration of water through the stomata
E) adhesion of water to phloem sieve tubes

Question 25

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.
E) The osmotic pressure of the cells would decrease.

Question 26

Which of the following statements is false concerning the xylem?

A) Xylem tracheids and vessels fulfill their vital function only after their death.
B) The cell walls of the tracheids are greatly strengthened with lignin and cellulose fibrils forming thickened rings or spirals.
C) Water molecules are transpired from the cells of the leaves, and replaced by water molecules in the xylem pulled up from the roots due to the cohesion of water molecules.
D) Movement of materials is by mass flow; solutes in xylem sap move due to a positive turgor pressure gradient from source to sink.
E) In the morning, sap in the xylem begins to move first in the twigs of the upper portion of the tree, and later in the lower trunk.

Question 27

Phloem transport of sucrose is often described as going from source to sink. Which of the following would not normally function as a sink?

A) growing leaf
B) growing root
C) storage organ in summer
D) mature leaf
E) shoot tip

Question 28

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) nucleic acids; flower; root
D) proteins; root; leaf
E) sugars; stem; root

Question 29

Guard cells do which of the following?

A) protect the endodermis
B) accumulate K+ in order to close the stomata
C) contain chloroplasts that import K+ directly into the cells
D) guard against mineral loss through the stomata
E) help balance the photosynthesis-transpiration compromise

Question 30

In which plant cell or tissue would the pressure component of water potential most often be negative?

A) leaf mesophyll cell
B) stem xylem
C) stem phloem
D) root cortex cell
E) root epidermis

Question 31

Which of the following does not involve active transport across membranes?

A) the movement of mineral nutrients from the apoplast to the symplast
B) the movement of mineral nutrients from mesophyll cells into xylem cells
C) the movement of sugar from one sieve-tube element to the next
D) the movement of K+ across guard cell membranes during stomatal opening
E) the movement of mineral nutrients into cells of the root cortex

Question 32

Which of the following is not an important component of the long-distance transport process in plants?

A) the cohesion of water molecules
B) a negative water potential
C) the root parenchyma
D) the active transport of solutes
E) bulk flow from source to sink

Question 33

What is the role of proton pumps in root hair cells?

A) establish ATP gradients
B) maintain the H+ gradient
C) pressurize xylem transport
D) eliminate excess electrons
E) assist in active uptake of water molecules

Question 34

The following factors may sometimes play a role in the movement of sap through xylem. Which one depends on the direct expenditure of ATP by the plant?

A) capillarity of water within the xylem
B) evaporation of water from leaves
C) cohesion among water molecules
D) concentration of ions in the symplast
E) bulk flow of water in the root apoplast

Question 35

Water flows into the source end of a sieve tube because

A) sucrose has diffused into the sieve tube, making it hypotonic.
B) sucrose has been actively transported into the sieve tube, making it hypertonic.
C) water pressure outside the sieve tube forces in water.
D) the companion cell of a sieve tube actively pumps in water.
E) sucrose has been transported out of the sieve tube by active transport.

Question 36

One would expect to find the highest density of aquaporins in which of the following?

A) the plasma membrane of guard cells
B) the pits of a tracheid
C) the plasma membrane of parenchyma cells in a ripe fruit
D) the plasma membrane of a mature mesophyll cell in a leaf
E) the membrane lining plasmodesmata

Question 37

The opening of stomata is thought to involve

A) an increase in the solute concentration of the guard cells.
B) a decrease in the solute concentration of the stoma.
C) active transport of water out of the guard cells.
D) decreased turgor pressure in the guard cells.
E) movement of K+ from the guard cells.

Question 38

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.
E) Sugar transport does not require energy.

Question 39

Which of the following essential nutrients plays an essential role in the opening and closing of the stomatal aperture?

A) Fe
B) Bo
C) Mg
D) H
E) K

Question 40

Photosynthesis begins to decline when leaves wilt because

A) chloroplasts within wilted leaves are incapable of photosynthesis.
B) CO2 accumulates in the leaves and inhibits the enzymes needed for photosynthesis.
C) there is insufficient water for photolysis during the light reactions.
D) stomata close, restricting CO2 entry into the leaf.
E) extreme heat causes photosynthetic enzymes to denature.

Question 41

Which of the following elements is incorrectly paired with its function in a plant?

A) nitrogen-component of nucleic acids, proteins, hormones, coenzymes
B) magnesium-component of chlorophyll; activates many enzymes
C) phosphorus-component of nucleic acids, phospholipids, ATP, several coenzymes
D) potassium-cofactor functional in protein synthesis, osmosis, operation of stomata
E) sulfur-component of DNA; activates some enzymes

Question 42

For this pair of items, choose the option that best describes their relationship. (a) The average size of particles that constitute silt
(b) The average size of particles that constitute clay

A) Item (a) is larger than item (b).
B) Item (a) is smaller than item (b).
C) Item (a) is exactly or very approximately equal to item (b).
D) Item (a) bears no relationship to item (b).

Question 43

Several properties are characteristic of a soil in which typical plants would grow well. Of the following, which would be the least conducive to plant growth?

A) abundant humus
B) numerous soil organisms
C) compacted soil
D) high porosity
E) high cation exchange capacity

Question 44

Which of the following would be in the lowest concentration in an actively growing shoot tip?

A) zinc
B) nitrogen
C) phosphorus
D) potassium
E) calcium

Question 45

Reddish-purple coloring of leaves, especially along the margins of young leaves, is a typical symptom of deficiency of which element?

A) C
B) Mg2+
C) N
D) P
E) K+

Question 46

The bulk of a plant's dry weight is derived from

A) soil minerals.
B) CO2.
C) the hydrogen from H2O.
D) the oxygen from H2O.
E) the uptake of organic nutrients from the soil.

Question 47

A soil well suited for the growth of most plants would have all of the following properties except

A) abundant humus.
B) air spaces.
C) good drainage.
D) high cation exchange capacity.
E) a high pH.

Question 48

Why does overwatering a plant kill it?

A) Water does not have all the necessary minerals a plant needs to grow.
B) Water neutralizes the pH of the soil.
C) The roots are deprived of oxygen.
D) Water supports the growth of root parasites.
E) Water lowers the water potential of the roots.

Question 49

For this pair of items, choose the option that best describes their relationship. (a) The amount of molybdenum in a gram of dried plant material
(b) The amount of sulfur in a gram of dried plant material

A) Item (a) is greater than item (b).
B) Item (a) is less than item (b).
C) Item (a) is exactly or very approximately equal to item (b).
D) There is not enough information to make a meaningful comparison.

Question 50

Which two elements make up more than 90% of the dry weight of plants?

A) carbon and nitrogen
B) oxygen and hydrogen
C) nitrogen and oxygen
D) oxygen and carbon
E) carbon and potassium

Question 51

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) 2, 1, 4, 3, 5
B) 1, 2, 3, 4, 5
C) 2, 4, 3, 1, 5
D) 4, 2, 1, 3, 5
E) 2, 4, 1, 3, 5

Question 52

What is a major function of magnesium in plants?

A) to be a component of lignin-biosynthetic enzymes
B) to be a component of DNA and RNA
C) to be a component of chlorophyll
D) to be active in amino acid formation
E) to be required to regenerate phosphoenolpyruvate in C4 and CAM plants

Question 53

Most of the dry weight of a plant is derived from

A) NO3- and CO2.
B) K+ and CO2.
C) PO43- and K+.
D) H2O and K+.
E) H2O and CO2.

Question 54

Which of the following soil minerals is most likely leached away during a hard rain?

A) Na+
B) K+
C) Ca2+
D) NO3-
E) H+

Question 55

If you wanted to increase the cation exchange and water retention capacity of loamy soil, what should you do?

A) Adjust the soil pH to 7.9.
B) Add clay to the soil.
C) Practice no-till agriculture.
D) Add fertilizer containing potassium, calcium, and magnesium to the soil.
E) Increase the number of sand particles in the soil.

Question 56

Synthesis of which of the following compounds in a mature leaf would be least impacted by a temporary soil nitrogen deficiency?

A) chlorophyll
B) DNA
C) RNA
D) amino acids
E) cellulose

Question 57

The NPK percentages on a package of fertilizer refer to the

A) total protein content of the three major ingredients of the fertilizer.
B) percentages of manure collected from different types of animals.
C) relative percentages of organic and inorganic nutrients in the fertilizer.
D) percentages of three important mineral nutrients.
E) proportions of three different nitrogen sources.

Question 58

In hydroponic culture, what is the purpose of bubbling air into the solute?

A) to keep dissolved nutrients evenly distributed
B) to provide oxygen to the root cells
C) to inhibit the growth of aerobic algae
D) to inhibit the growth of anaerobic bacteria
E) to provide CO2 for photosynthesis

Question 59

For this pair of items, choose the option that best describes their relationship. (a) The amount of nitrogen in a fertilizer marked "15-10-5"
(b) The amount of nitrogen in a fertilizer marked "15-5-5"

A) Item (a) is greater than item (b).
B) Item (a) is less than item (b).
C) Item (a) is exactly or very approximately equal to item (b).
D) Item (a) is unrelated to item (b).

Question 60

Which of the following elements is required for the stability of cell walls?

A) zinc
B) chlorine
C) calcium
D) molybdenum
E) manganese

Question 61

Which of the following is a primary difference between ectomycorrhizae and endomycorrhizae?

A) Endomycorrhizae have thicker, shorter hyphae than ectomycorrhizae.
B) Endomycorrhizae, but not ectomycorrhizae, form a dense sheath over the surface of the root.
C) Ectomycorrhizae do not penetrate root cells, whereas endomycorrhizae grow into invaginations of the root cell membranes.
D) Ectomycorrhizae are found in woody plant species; about 85% of plant families form ectomycorrhizae.
E) There are no significant differences between ectomycorrhizae and endomycorrhizae.

Question 62

A rootless, green plant is found growing on the branches and trunks of rain forest trees, but lacks any apparent adaptation for collecting rainwater. This plant is most likely

A) an epiphyte.
B) a nitrogen-fixing plant.
C) a carnivorous plant.
D) a symbiotic plant.
E) a parasite.

Question 63

The most efficient way to increase essential amino acids in crop plants for human consumption would be to

A) breed for higher yield of deficient amino acids.
B) increase the amount of fertilizer used on fields.
C) use 20-20-20 fertilizer instead of 20-5-5 fertilizer.
D) engineer nitrogen-fixing nodules into crop plants lacking them.
E) increase irrigation of nitrogen-fixing crops.

Question 64

You are weeding your garden when you accidentally expose some roots of your pea plants. You notice swellings (root nodules) on the roots and there is a reddish tinge to the ones you accidentally damaged. Most likely your peas plants

A) suffer from a mineral deficiency.
B) are infected with a parasite.
C) are benefiting from a mutualistic bacterium.
D) are developing offshoots from the root.
E) contain developing insect pupa.

Question 65

Carnivorous plants have evolved mechanisms that trap and digest small animals. The products of this digestion are used to supplement the plant's supply of

A) energy.
B) carbohydrates.
C) lipids and steroids.
D) minerals.
E) water.

Question 66

Which of the following is not a function of rhizobacteria?

A) produce hormones that stimulate plant growth
B) produce antibiotics that protect roots from disease
C) absorb toxic metals
D) carry out nitrogen fixation
E) supply growing roots with glucose

Question 67

Which of the following is not true of micronutrients in plants?

A) They are elements required in relatively small amounts.
B) They are required for a plant to grow from a seed and complete its life cycle.
C) They generally help in catalytic functions in the plant.
D) They are the essential elements of small size and molecular weight.
E) Deficiencies vary widely by soil type.

Question 68

An example of a mutualistic association between a plant and a fungus would be

A) nitrogen fixation.
B) Rhizobium infection.
C) mycorrhizae.
D) parasitic infection.
E) assisted pollination.

Question 69

The enzyme complex nitrogenase catalyzes the reaction that reduces atmospheric nitrogen to

A) N2
B) NH3
C) NO2
D) NO+
E) NO-

Question 70

If a plant is infected with nitrogen-fixing bacteria, what is the most probable effect on the plant?

A) It gets chlorosis.
B) It dies.
C) It will have a higher concentration of N2 in its roots and shoots.
D) It will likely grow faster than an uninfected plant.
E) It becomes flaccid due to the loss of water and nutrients from the roots.

Question 71

Which of the following is a true statement about nitrogen fixation in root nodules?

A) The plant contributes the nitrogenase enzyme.
B) The process is relatively inexpensive in terms of ATP costs.
C) Leghemoglobin helps maintain a low O2 concentration within the nodule.
D) The process tends to deplete nitrogen compounds in the soil.
E) The bacteria of the nodule are autotrophic.

Question 72

Which of the following, if used as a fertilizer, would be most immediately available for plant uptake?

A) NH3
B) N2
C) CN2H2
D) NO3
E) amino acids

Question 73

The earliest vascular plants on land had underground stems (rhizomes) but no roots. Water and mineral nutrients were most likely obtained by

A) absorption by hairs and trichomes.
B) diffusion through stomata.
C) absorption by mycorrhizae.
D) osmosis through the root hairs.
E) diffusion across the cuticle of the rhizome.

Question 74

What are epiphytes?

A) aerial vines common in tropical regions
B) haustoria used for anchoring to host plants and obtaining xylem sap
C) plants that live in poor soil and digest insects to obtain nitrogen
D) plants that grow on other plants but do not obtain nutrients from their hosts
E) plants that have a symbiotic relationship with fungi

Question 75

Iron deficiency is often indicated by yellowing in newly formed leaves. This suggests that iron

A) is a relatively immobile nutrient in plants.
B) is tied up in formed chlorophyll molecules.
C) is concentrated in the xylem of older leaves.
D) is concentrated in the phloem of older leaves.
E) is found in leghemoglobin and reduces the amount available to new plant parts.

Question 76

Upregulation of leghemoglobin biosynthesis in a leguminous species would most likely indicate

A) the plant is suffering from a mineral deficiency.
B) the successful inoculation of nitrogen-fixing bacteria.
C) the plant is suffering from water stress.
D) the plant has been infected with mycorrhizae.
E) an increase in the biosynthesis of amino acids.

Question 77

A corn (Zea mays) mutant is developed that is impaired in magnesium uptake. The most likely phenotypic expression would be

A) chlorosis, especially in the older leaves.
B) a purple tinge to actively growing shoots.
C) severely stunted root growth and branching.
D) a reduction in leaf surface area.
E) a delay in flowering.

Question 78

In a root nodule, the gene coding for nitrogenase

A) is inactivated by leghemoglobin.
B) is absent in active bacteroids.
C) is found in the cells of the pericycle.
D) protects the nodule from nitrogen.
E) is part of the Rhizobium genome.

Question 79

If an African violet has chlorosis, which of the following elements might be a useful addition to the soil?

A) chlorine
B) molybdenum
C) copper
D) iodine
E) magnesium

Question 80

Hyphae form a covering over roots. These hyphae create a large surface area that helps to do which of the following?

A) aid in absorbing minerals and ions
B) maintain cell shape
C) increase cellular respiration
D) anchor a plant
E) protect the roots from ultraviolet light