Deck 39: Plant Responses to Environmental Challenges

Question 1

Halophytes

A) may accumulate abscisic acid in their vacuoles.
B) may have water potentials that are lower than those of other plants.
C) only accumulate sodium.
D) have low root-to-shoot ratios.
E) rarely accumulate sodium.

Answer 1

C

Question 2

Plants that tolerate heavy metals commonly

A) differ genetically from other members of their species.
B) do not take up the heavy metals.
C) are tolerant to all heavy metals.
D) are slow to colonize an area rich in heavy metals.
E) weigh more than plants that are sensitive to heavy metals.

Answer 2

A

Question 3

Phytoalexins

A) are always present in plants.
B) occur in uniform concentration throughout a plant.
C) are toxic to many fungi and bacteria.
D) have no effect on viral infections.
E) None of the above

Answer 3

C

Question 4

In defense against tissue damage caused by pathogens,

A) animals repair damaged tissues and plants seal off damaged tissues.
B) animals seal off damaged tissues and plants repair damaged tissues.
C) both plants and animals sometimes seal off and sometimes repair damaged tissues.
D) both plants and animals repair damaged tissues.
E) both plants and animals seal off damaged tissues.

Question 5

Which statement about secondary metabolites is not true?

A) They may be used in defense against fungi.
B) Some are poisonous to herbivores.
C) Some are amino acids that are normally part of proteins.
D) Water soluble molecules are stored in vacuoles.
E) Some mimic the hormones of animals.

Question 6

Polysaccharides serve to

A) store water in plants.
B) defend against pathogens.
C) repel predators because they are toxic to animals.
D) act as salt glands.
E) strengthen cell walls to form a barrier against invasion of a pathogen.

Question 7

In order for an R gene to confer resistance, an invader must have a corresponding

A) R gene.
B) tRNA.
C) virus.
D) Avr gene.
E) bacterium.

Question 8

Plants sometimes protect themselves from their own toxic secondary metabolites by

A) producing special enzymes that destroy the toxin.
B) storing precursors of the toxic substances in one compartment and the enzymes that convert those precursors to toxic products in another compartment.
C) storing the toxic substances in mitochondria or chloroplasts.
D) distributing the toxic substances to all cells of the plant.
E) performing crassulacean acid metabolism.

Question 9

Which of the following is not an adaptation to dry environments?

A) Increased solute concentration in the vacuoles
B) Hairy leaves
C) A heavier cuticle over the leaf epidermis
D) Sunken stomata
E) A root system that grows each rainy season and dies back when it is dry

Question 10

In the gene-for-gene resistance mechanism, if a plant has a resistance gene and a pathogen has the matching avirulence gene,

A) the pathogen's gene overrides the plant's gene and infects the plant.
B) the plant will become susceptible to the pathogen.
C) the plant is resistant to the pathogen.
D) the plant is resistant to all pathogens, whether or not they have the avirulence gene.
E) None of the above

Question 11

A plant's first line of defense is its

A) outer surface.
B) root system.
C) apical meristem.
D) lenticels.
E) vascular system.

Question 12

Which statement about latex is not true?

A) It is sometimes contained in laticifers.
B) It is typically white.
C) It is often toxic to insects.
D) It is a rubbery solid.
E) Milkweeds produce it.

Question 13

Which of the following is not a common defense against bacteria and fungi?

A) Lignin formation
B) Phytoalexins
C) A waxy covering
D) The hypersensitive response
E) Mycorrhizae

Question 14

Pathogens employ _______ genes that code for molecules called elicitors.

A) phytoalexin
B) hypersensitive-response
C) extensin
D) lignin
E) avirulence

Question 15

Herbivory

A) is an attack by plants on animals.
B) always reduces plant growth.
C) usually increases the rate of photosynthesis in the remaining leaves.
D) reduces the rate of transport of photosynthetic products from the remaining leaves.
E) is always lethal to the grazed plant.

Question 16

Phytoalexin production is an example of

A) a constitutive plant defense.
B) an environmental challenge.
C) an induced plant defense.
D) a mechanical defense.
E) a constitutive and induced plant defense.

Question 17

The ability of plants to employ resistance genes to counter pathogen avirulence genes is called

A) physical isolation.
B) a receptor mechanism.
C) gene-for-gene resistance.
D) a pathogen response.
E) signaling.

Question 18

Which of the following is not involved in the response to drought stress?

A) Abscisic acid
B) Closing of aquaporins
C) LEA gene expression
D) Closing of stomata
E) Jasmonate

Question 19

Some plants adapted to swampy environments meet the oxygen needs of their roots by means of a specialized tissue called

A) parenchyma.
B) aerenchyma.
C) collenchyma.
D) sclerenchyma.
E) chlorenchyma.

Question 20

Plants employ _______ genes that code for molecules called receptors.

A) resistance
B) pathogen
C) bacterial
D) signal transduction
E) None of the above

Question 21

The ability of grasses to grow from the base of the shoot and leaf is an adaptation to

A) dry environments.
B) soil fungi.
C) heavy metals.
D) grazing.
E) saline environments.

Question 22

Typically, when some leaves are removed from a plant,

A) less light is available to the remaining leaves.
B) less nitrogen is obtained from the soil.
C) the plant dies.
D) the rate of photosynthesis in the remaining leaves increases.
E) the transport of sugar from the remaining leaves decreases.

Question 23

The nicotine in tobacco is an example of a plant

A) alkaloid.
B) flavonoid.
C) glycoside.
D) steroid.
E) tannin.

Question 24

Which of the following are "secondary products"?

A) Proteins
B) Lipids
C) Alkaloids
D) Carbohydrates
E) Nucleic acids

Question 25

The proteins that enhance a plant's response to attack are called

A) pathogenesis-related proteins.
B) expansins.
C) antibiotics.
D) phytoalexins.
E) local defenders.

Question 26

According to some data, a unique feature of oil of wintergreen is that it can stimulate production of PR protein in

A) leaves.
B) roots.
C) flowering regions.
D) a plant harboring an infection.
E) plants neighboring the infected plant that produced it.

Question 27

The fatty acid derivative jasmonate is a

A) nucleic acid.
B) steroid.
C) hormone.
D) protease.
E) polypeptide.

Question 28

One way that grazing increases the productivity of a plant is by

A) supporting food chains in nature.
B) reducing the rate of photosynthesis in remaining leaves.
C) increasing the number of sinks for absorbed nitrogen.
D) shading younger leaves.
E) causing the production of more replacement stems.

Question 29

An RNA virus attack on a plant triggers the production of interference RNA (RNAi), which is derived from the RNA of the _______ and causes the plant to _______.

A) virus; die from a viral infection
B) plant; become immune to the virus
C) plant; form mechanical barriers
D) virus; become immune to the virus
E) virus; form mechanical barriers

Question 30

Grazing can increase photosynthetic production by

A) causing increased branching.
B) removing old or dead leaves.
C) providing increased root nutrients to the remaining leaves.
D) All of the above
E) None of the above

Question 31

Which of the following is not a hypersensitive reaction of a plant to infection?

A) Production of phytoalexins by cells around the infection
B) Death of cells near the infection
C) Death of infected cells
D) Synthesis of pathogenesis-related proteins
E) Transport of phytoalexins to all parts of the plant

Question 32

Secondary metabolites

A) are essential for basic biological reactions.
B) are similar in all plants.
C) occur more often in animals than in plants.
D) may attract or inhibit other organisms.
E) are usually of high molecular weight.

Question 33

Some plants produce the amino acid canavanine, which is toxic to many insects because it

A) inhibits respiration.
B) causes defects in protein structure and function.
C) interferes with protein digestion in the gut.
D) burns tissues due to its high acidity.
E) inhibits the synthesis of reproductive hormones.

Question 34

Grazing increases photosynthetic rates in certain plant species because

A) it allows more light to reach younger, more active leaves.
B) older leaves transport sugars more slowly to the roots.
C) it allows the roots to take up more nitrogen.
D) older, dying leaves are sugar sinks.
E) it reduces competition for atmospheric carbon dioxide.

Question 35

Steroids produced by plants may

A) attract pollinators and animals that disperse seeds.
B) affect the nervous systems of animals.
C) inhibit fungal action.
D) prevent normal development in insects.
E) impair growth of competing plants.

Question 36

Defensive, water-soluble secondary compounds formed by plants are usually stored in the

A) vacuoles.
B) nuclei.
C) cell walls.
D) cytoplasm.
E) membrane proteins.

Question 37

Salicylic acid in plants does not

A) increase resistance to pathogens.
B) trigger the production of pathogenesis-related proteins.
C) cause herbivorous insects to produce defective proteins.
D) protect against tobacco mosaic virus.
E) play a role in the defensive response.

Question 38

Defensive secondary metabolites can affect insect

A) nervous systems.
B) digestive systems.
C) life cycles.
D) protein synthesis.
E) All of the above

Question 39

Grazed plants may exhibit increased productivity because of

A) increased photosynthetic rates.
B) growth of more stems.
C) greater fruit production.
D) All of the above
E) None of the above

Question 40

Plants can be treated with _______ to stimulate the production of pathogenesis-related proteins.

A) salicylic acid
B) PR inducer
C) phytoalexin
D) cellulose
E) willowgen

Question 41

The pneumatophores of swamp plants are modified

A) flowers.
B) leaves.
C) roots.
D) spines.
E) stems.

Question 42

Which combination of adaptations is often observed in plants found in saline environments?

A) Salt glands and succulence
B) Salt glands and broad leaves
C) Spines and thin cuticles
D) Dense stomata and thick cuticles
E) Narrow leaves and dense stomata

Question 43

Which of the following is not an adaptation to a dry environment?

A) A deep taproot
B) Airborne roots
C) Higher accumulation of the amino acid proline
D) Fleshy leaves
E) Shallow but extensive root system

Question 44

Some halophytic plants have salt glands that

A) accumulate salt in their roots.
B) serve as barriers to salt intake.
C) maintain high salt concentrations in the plant.
D) secrete salt onto the leaf surface.
E) increase water loss from the plant.

Question 45

Non-water-soluble (hydrophobic) poisons are stored in a plant's

A) chloroplasts.
B) laticifers or epidermal waxes.
C) Golgi bodies.
D) mitochondria.
E) vacuoles.

Question 46

By accumulating the amino acid proline, plants

A) become toxic to most herbivores.
B) can carry out alcoholic fermentation.
C) can extract more water from the soil.
D) can avoid toxic effects from sodium.
E) attract animals that disperse seeds.

Question 47

Which of the following is not a method by which plants protect themselves from toxins they produce?

A) By compartmentalizing them
B) By building up a tolerance to them
C) By adjusting the timing of toxin production
D) By storing them in waxes
E) By storing them in vacuoles

Question 48

Plants can produce the respiratory poison cyanide without poisoning themselves because plants

A) do not respire.
B) store a cyanide precursor in one compartment and activating enzymes in another.
C) store water-soluble cyanide in laticifers.
D) possess enzymes that are unaffected by cyanide.
E) also produce proteins that bind and inhibit cyanide.

Question 49

High temperatures trigger heat shock proteins such as

A) nucleases.
B) kinases.
C) chaperonins.
D) antifreeze proteins.
E) proline.

Question 50

Swamp plants typically have root systems that

A) grow quickly.
B) penetrate deeply into the soil.
C) can carry out alcoholic fermentation.
D) alternate periods of growth with periods of dieback.
E) accumulate the amino acid proline.

Question 51

Plants that concentrate the harmless amino acid proline in their cells have

A) an increased negative water potential.
B) an increased rate of transpiration.
C) an increased resistance to grazing.
D) decreased salt loss.
E) decreased water uptake.

Question 52

Which of the following is the typical environment for an annual plant with a brief growing period and seeds capable of long dormant periods?

A) Desert
B) Salt marsh
C) Freshwater marsh
D) Environment contaminated with heavy metals
E) Grazed field

Question 53

Laticifers are

A) specialized cells for containing sodium ions.
B) latex-containing tubes for storing hydrophobic products.
C) waxy cells in the epidermis.
D) cells that produce poisons such as alkaloids.
E) cells in roots that take up water in dry environments.

Question 54

In conditions in which soil water is plentiful but oxygen is scarce, plants respond by

A) rapidly growing roots that penetrate deeply into the soil.
B) reverting to alcoholic fermentation.
C) inhibiting the production of ATP.
D) producing oxygen from water.
E) All of the above

Question 55

Which evidence best supports the hypothesis that the presence of toxic latex in leaves deters insects from feeding on a plant?

A) Many insects do not feed on latex-producing plants.
B) Latex-producing plants release a milky latex when their leaves are damaged.
C) Beetles that drain latex out of part of a leaf can then feed on that part.
D) Beetles that cut veins in the leaves can then feed on the released latex.
E) Latex-producing plants have high survival rates.

Question 56

Leaf parenchyma tissue with large spaces between cells _______ in _______.

A) provide buoyancy; aquatic plants
B) decrease transpiration; aquatic plants
C) store water; desert plants
D) form succulent leaves; desert plants
E) excrete salt; halophytes

Question 57

Which of the following is not a special adaptation of leaves to dry environments?

A) Modification into spines
B) Stomata in sunken cavities
C) Dense epidermal hairs
D) Fleshy leaves
E) Salt glands

Question 58

If a nonhalophyte and a halophyte are both placed in a salty environment, the _______ will accumulate more sodium internally, because _______.

A) halophyte; halophytes are adapted to saline environments
B) halophyte; it requires sodium as a nutrient
C) halophyte; as a succulent, it has more internal storage
D) nonhalophyte; it cannot excrete sodium after absorption
E) nonhalophyte; it requires sodium to create a negative water potential

Question 59

The presence of pneumatophores in plants is an adaptation for success in a _______ habitat.

A) desert
B) mountain
C) grassland
D) seashore
E) swamp

Question 60

Many halophytes accumulate the amino acid

A) proline.
B) arginine.
C) glycine.
D) methionine.
E) chlorine.

Question 61

Large molecules called _______ proteins are produced as a defense against infection and in cleanup operations.

Question 62

Which of the following elements is not a heavy metal?

A) Cadmium
B) Chromium
C) Lead
D) Mercury
E) Sulfur

Question 63

Which of the following is not an adaptation to a saline environment?

A) Accumulation and transport of sodium ions
B) Sequestering of sodium ions in roots
C) Salt glands in leaves
D) Fleshy, gummy leaves
E) Small leaves with small cells

Question 64

Some swamp plants have root extensions called _______ that grow into the air and deliver _______ to the rest of the root system.

Question 65

In cacti, leaves are modified to form _______, and photosynthesis is carried out in the _______ region.

Question 66

In aquatic plants, _______ tissue allows oxygen to reach submerged tissues.

Question 67

Some plants subjected to herbivory undergo increased _______.

Question 68

Plants with fleshy, water-storing leaves are called _______.

Question 69

Plants adapted to dry environments are called _______.

Question 70

When a plant detects an attack by an herbivorous insect, a(n) _______ pathway is initiated, which in turn activates defenses such as the production of protease inhibitors.

Question 71

Which of the following statements about plants and heavy metals is false?

A) Plants take up heavy metals.
B) Different populations of plants have the same capacity to tolerate heavy metals.
C) Tolerant populations of plants can evolve rapidly.
D) A plant's tolerance is determined by its genotype.
E) Plants in areas with heavy metals usually experience little competition.

Question 72

The major stress encountered by plants living in waterlogged soil is lack of _______.

Question 73

Plants produce antibiotics called _______ within hours of infection by fungi or bacteria.

Question 74

_______ proteins accumulate in maturing seeds, and are essential in drought resistance.

Question 75

The reason that certain plants can grow in soils con­taminated with high levels of heavy metals is that they

A) do not take up the heavy metals.
B) excrete the heavy metals.
C) have a genetic tolerance to the heavy metals.
D) use the heavy metals for normal biochemical functions.
E) are toxic to herbivores due to the heavy metals.

Question 76

Plants with long dormant periods interrupted by short periods of rapid growth and reproduction typically live in _______ environments.

Question 77

Plants limit the spread of viral pathogens by blocking their plasmodesmata with _______.

Question 78

Substances that are not used for basic cellular metabolism, but rather for special functions such as inhibiting other organisms, are called _______ metabolites.

Question 79

Canavanine is a(n) _______ amino acid that is synthesized by a plant to fight herbivorous insects.

Question 80

When cells accumulate the amino acid _______, their water potential becomes more negative.