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) water potentials.

Answer 1

D

Question 2

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.

Answer 2

A

Question 3

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.

Answer 3

A

Question 4

The symplast is the continuum of cytosol connected by

A) extracellular spaces.
B) apoplastic route.
C) plasmodesmata.
D) symplastic route.

Question 5

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.

Question 6

Which of the following was an essential adaptive feature for the evolution of plants from water to the land?

A) minimizing the evaporative loss of water
B) using light more effectively
C) acquiring CO₂ from the air
D) acquiring water from the ground

Question 7

The architecture and distribution of the root system and production of proteins in plants are directly relevant to the availability ________ in soil.

A) of carbon dioxide
B) and richness of nitrates
C) of fungal association
D) of water

Question 8

Which one of the following is an adaptation by plants to life on land?

A) lack of waxy cuticle
B) Calvin cycle of photosynthesis
C) xylem tracheids and vessels
D) Krebs cycle of respiration

Question 9

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.

Question 10

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) help balance the photosynthesis-transpiration compromise

Question 11

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.

Question 12

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.

Question 13

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) 0.0 (zero).

Question 14

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

Question 15

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 phloem.

Question 16

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

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.

Question 18

Typically, on average, what percentage of a plant's fresh biomass is water?

A) 70-75
B) 65-75
C) 80-90
D) 75-80

Question 19

Which of the following determines the direction of water movement across the membrane?

A) cell health
B) a difference in water potential
C) size of the cell
D) shape of the cell

Question 20

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

Question 21

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

Question 22

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 23

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.

Question 24

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

Question 25

Atmospheric nitrogen can be fixed by nitrogen-fixing bacteria. Arrange the following forms of nitrogen from the atmospheric N stage to the final form that enters the roots.
1) Ammonia
2) Nitrogen gas
3) Ammonium ion
4) Nitrite
5) Nitrate

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

Question 26

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.

Question 27

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.

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

Question 29

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.

Question 30

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

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

Question 31

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

A) leaf transfer cells
B) stem tracheid element
C) root endodermal cells
D) leaf mesophyll cells

Question 32

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

Question 33

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

Question 34

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.

Question 35

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

Question 36

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

Question 37

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 38

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) K

Question 39

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

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

Question 40

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

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

Question 41

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

Question 42

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.

Question 43

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.

Question 44

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

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

Question 45

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.

Question 46

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

A) N2.
B) NH3.
C) NO₂-.
D) NO+.

Question 47

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

Question 48

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.

Question 49

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) is part of the Rhizobium genome.

Question 50

Copper plays a critical role in ________ of plant cells.

A) water splitting in photosynthesis
B) redox reactions and lignin-biosynthetic enzymes
C) cytochromes
D) cofactor for enzymes needed for nitrogen fixation

Question 51

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

Question 52

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 CO₂.

Question 53

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

Question 54

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.

Question 55

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 pea plants

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

Question 56

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

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

Question 57

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) cellulose

Question 58

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.

Question 59

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-

Question 60

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

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.

Question 61

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.

Question 62

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.

Question 63

Nitrogen fixation is a process that

A) recycles nitrogen compounds from dead and decaying materials.
B) converts ammonia to ammonium.
C) releases nitrate from the rock substrate.
D) converts nitrogen gas into ammonia.

Question 64

In what way do nitrogen compounds differ from other minerals needed by plants?

A) Only nitrogen can be lost from the soil.
B) Only nitrogen requires the action of bacteria to be made available to plants.
C) Only nitrogen is held by cation exchange capacity in the soil.
D) Only nitrogen can be absorbed by root hairs.

Question 65

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

Question 66

Which of the following would be the most effective strategy to remove toxic heavy metals from a soil?

A) heavy irrigation to leach out the heavy metals
B) application of fertilizers to compete with heavy metal uptake
C) adding plant species that have the ability to take up and accumulate heavy metals
D) inoculating soil with mycorrhizae to avoid heavy metal uptake

Question 67

Which of the following plant structures shares the most common features and functions with a fungal hyphae?

A) stomata
B) vascular cambium
C) lenticels
D) root hairs

Question 68

The Casparian strip in plant roots is correctly described by which of the following?

A) It aids in the uptake of nutrients.
B) It provides energy for the active transport of minerals into the stele from the cortex.
C) It ensures that all minerals are absorbed from the soil in equal amounts.
D) It ensures that all water and dissolved substances must pass through a cell membrane before entering the stele.

Question 69

Pine seedlings grown in sterile potting soil grow much slower than seedlings grown in soil from the area where the seeds were collected. This is most likely because

A) the sterilization process kills the root hairs as they emerge from the seedling.
B) the normal symbiotic fungi are not present in the sterilized soil.
C) water and mineral uptake is faster when mycorrhizae are present.
D) B and C.

Question 70

Rhizobia, actinomycetes, and cyanobacteria all share the common feature that they can

A) increase water uptake in plants.
B) increase nutrient availability in the soil for plants.
C) kill parasites in the soil.
D) fix atmospheric nitrogen.

Question 71

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) Proton pumps reversed the membrane potential.

Question 72

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) absorption by mycorrhizae.
C) osmosis through the root hairs.
D) diffusion across the cuticle of the rhizome.

Question 73

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) an increase in the biosynthesis of amino acids.

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

Question 75

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) the Casparian strip
B) a guard cell
C) the root epidermis
D) the endodermis

Question 76

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) protect the roots from ultraviolet light

Question 77

Why is nitrogen fixation an essential process?

A) Nitrogen fixation can only be done by certain prokaryotes.
B) Fixed nitrogen is often the limiting factor in plant growth.
C) Nitrogen fixation is very expensive in terms of metabolic energy.
D) Nitrogen fixers are sometimes symbiotic with legumes.

Question 78

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) minerals.
D) water.

Question 79

Root hairs are most important to a plant because they

A) anchor a plant in the soil.
B) store starches.
C) increase the surface area for absorption.
D) provide a habitat for nitrogen-fixing bacteria.

Question 80

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 parasite.