Deck 28: Plants in the Environment

Question 1

Upon sensing the presence of a pathogen,a plant begins synthesizing chemicals to defend against it.This response is known as a(n)

A) arms race.
B) evoked defense.
C) induced defense.
D) elicited defense.
E) constitutive defense.

Answer 1

C

Question 2

A fungus infection occurs in the leaves of a plant.This triggers a variety of immune responses,including the production of salicylic acid,which then travels to other parts of the plant.These parts of the plant are later resistant to infection by other fungi.The plant is showing the results of

A) specific immunity.
B) constitutive defenses.
C) hypersensitive response.
D) systemic acquired resistance.
E) gene-for-gene resistance.

Answer 2

D

Question 3

A specific immune response triggered by a pathogen involves several steps.Which of these steps occurs first?

A) R proteins trigger specific immune responses.
B) PR proteins signal cells that have not yet been attacked.
C) Effector binds to cytoplasmic receptor (R protein)inside the cell.
D) Signaling molecules in the cell trigger production of defensive molecules.
E) Substances are produced to strengthen the cell wall and block plasmodesmata.

Answer 3

C

Question 4

The plant immune system is similar to the human immune system except that plants,but not humans,

A) have both general and specific immunity.
B) have protective structures and substances on their outer surfaces.
C) have receptors that recognize molecules produced by pathogens.
D) produce molecules that deter both pathogens and predators.
E) produce specific recognition molecules for many different pathogens.

Question 5

A plant's first line of defense against pathogens is its

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

Question 6

Which substance is produced in specific immunity but not in general immunity?

A) Nitric oxide
B) siRNAs
C) Jasmonic acid
D) Phytoalexins
E) Hydrogen peroxide

Question 7

Tobacco contains a resistance gene that recognizes a specific avirulence gene in tobacco mosaic virus (TMV)and mobilizes the plant's defenses against it.This is an example of

A) general immunity.
B) gene-for-gene resistance.
C) a hypersensitive response.
D) systemic acquired resistance.
E) a pathogen associated molecular pattern.

Question 8

A plant's ability to produce the enzyme chitinase would be most valuable in controlling which type of plant pathogen?

A) Virus
B) Fungus
C) Bacterium
D) Protozoan
E) Herbivore

Question 9

The presence of necrotic lesions on the leaves of a plant would suggest that the plant

A) cannot fight off a pathogen.
B) has been killed by a pathogen.
C) has prevented a pathogen from spreading.
D) has successfully fought off a pathogen.
E) has stopped a pathogen,but only temporarily.

Question 10

Some soybeans are susceptible to a disease called bacterial blight.A plant geneticist wants to genetically engineer a soybean that is resistant to this disease and needs to find a gene to splice into the plant.The scientist would most likely look for

A) a resistance (R)gene in the susceptible soybean.
B) a resistance (R)gene in an unsusceptible organism.
C) an avirulence (Avr)gene in the soybean.
D) an avirulence (Avr)gene in an unsusceptible organism.
E) an avirulence (Avr)gene in the bacterial pathogen.

Question 11

A gene in a petunia plant produces an integral membrane protein that is involved in helping the petunia resist pathogens.This gene probably codes for a

A) PAMP.
B) receptor protein.
C) cytoskeletal protein.
D) effector protein.
E) transporter protein.

Question 12

When a plant responds to a pathogen,which substance would likely be produced last and would be involved in a slow-acting response against the pathogen?

A) PR protein
B) Salicylic acid
C) Phytoalexin
D) Nitric oxide
E) Hydrogen peroxide

Question 13

Constitutive defenses of plants include all of the following except

A) cutin.
B) wax.
C) suberin.
D) elicitors.
E) cell walls.

Question 14

Which type of organism is not classified as a plant pathogen?

A) Virus
B) Fungus
C) Protist
D) Bacterium
E) Herbivore

Question 15

Which statement about an induced response to pathogens is true?

A) It is triggered by a PAMP.
B) It can never be genetically determined.
C) It is activated when constitutive defenses fail.
D) It is the first line of defense against pathogens.
E) It is always present and can be initiated at any time.

Question 16

What is a major difference between general and specific immunity in plants?

A) Only specific immunity requires activation by a trigger.
B) Only specific immunity involves changes in gene expression.
C) General immunity is much stronger than specific immunity.
D) General immunity is triggered by proteins;specific immunity is triggered by lipids or phospholipids.
E) General immunity responds to entire groups of pathogens;specific immunity responds to individual pathogens.

Question 17

Plant cell receptors that recognize the molecule chitin activate signaling pathways that lead to production of the enzyme chitinase,which breaks down chitin.In this situation,chitin is a(n)_______ and the overall response is called _______ immunity.

A) PAMP;general
B) PAMP;specific
C) effector;general
D) effector;specific
E) receptor;specific

Question 18

A plant produces the substance camalexin in response to a pathogen.Before camalexin could be produced,which type of gene had to be activated in the plant?

A) A PAMP gene
B) An avirulence (Avr)gene
C) A resistance (R)gene
D) A pathogenesis-related (PR)gene
E) A gene coding for a phytoalexin synthetase

Question 19

Fungi can directly enter and infect plant cells.Production of which type of molecule would likely be most effective at preventing fungi from entering the cells or from spreading to other cells?

A) Lignin
B) Chitin
C) Avr gene
D) Flagellin
E) siRNA

Question 20

The thick bark of a tree that deters pathogens from entering and protects the tree from herbivores is an example of a(n)

A) elicitor.
B) immune system.
C) evoked defense.
D) induced defense.
E) constitutive defense.

Question 21

Which of the following would most likely function as a plant's "first line of defense" against an herbivore?

A) Trichomes
B) Canavanine
C) Production of jasmonic acid
D) Change in cell membrane potential
E) Secondary metabolite that inhibits development

Question 22

Compounds such as methyl salicylate and volicitin are volatile.This quality enables them to aid in plant defenses by

A) speeding up the plant's immune responses.
B) turning off the production of PR proteins.
C) stimulating immune responses in neighboring plants.
D) stimulating immune responses in other parts of the plant.
E) providing a unique form of immunity that is neither constitutive nor induced.

Question 23

The characteristic defining a plant chemical as a secondary metabolite is that the chemical

A) is a small molecule.
B) mimics insect hormone actions.
C) damages the nervous systems of herbivores.
D) is released when herbivores damage the plant.
E) is used for basic plant functions such as respiration and synthesis.

Question 24

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

A) resistant only to that pathogen.
B) resistant to all pathogens.
C) susceptible only to that pathogen.
D) susceptible to all pathogens.
E) able to trigger the hypersensitive response.

Question 25

To initiate an induced immune response to herbivory,a plant must first sense the herbivore's attack.It does this when the herbivore's attack causes either

A) a neurotoxic response or inhibited respiration.
B) a neurotoxic response or a change in membrane potential.
C) release of a chemical elicitor or a change in membrane potential.
D) release of a secondary metabolite or release of a chemical elicitor.
E) a response to trichomes or other surface structures or release of a chemical elicitor.

Question 26

Most herbivores belong to which animal group?

A) Birds
B) Insects
C) Reptiles
D) Mammals
E) Amphibians

Question 27

A plant producing high levels of methyl salicylate and synthesizing large numbers of PR proteins is most likely showing

A) necrotic lesions.
B) a constitutive defense.
C) a hypersensitive response.
D) systemic acquired resistance.
E) a response to herbivores.

Question 28

Attacks on plants by herbivores differ from attacks by pathogens since herbivores

A) cause most of their damage by physically feeding on plants.
B) are all generalists,feeding on many different types of plants.
C) cause most of their damage by producing secondary metabolites.
D) are all specialists,feeding on only one type of plant.
E) cannot be controlled by constitutive or induced defenses.

Question 29

The toxicity of the secondary metabolite canavanine is based on its ability to

A) inhibit respiration.
B) act as a neurotoxin.
C) alter protein structure.
D) deter insects from feeding.
E) damage the digestive tract.

Question 30

One way systemic acquired resistance in plants differs from the hypersensitive reaction is that it

A) only acts against viruses.
B) affects only a small region of the plant.
C) begins with the production of salicylic acid.
D) uses apoptosis as a major mechanism of action.
E) only acts on the pathogen that originally triggered it.

Question 31

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

A) Transport of phytoalexins to all parts of the plant
B) Death of cells near the infection
C) Synthesis of polysaccharides to seal off the infection
D) Death of infected cells
E) Production of phytoalexins by cells around the infection

Question 32

Why does the change in cell membrane potential occur so quickly when an herbivore attacks a plant?

A) The response relies on chemicals that are already present in the plant.
B) The response relies on chemical signals,which are always rapid.
C) The response relies on an elicitor,which can be made quickly.
D) The membrane is the cell structure closest to the environment.
E) Both b and c

Question 33

Production of siRNAs in plant immunity results in _______,which provides the plant with systemic resistance against _______.

A) recombinant DNA;viruses
B) RNA degradation;bacteria
C) RNA interference;viruses
D) RNA interference;bacteria
E) RNA degradation;both viruses and bacteria

Question 34

An RNA virus attack on a plant triggers the production of siRNA.These siRNAs are derived from the RNA of the _______ and cause the plant to _______.

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

Question 35

To stimulate the production of pathogenesis-related proteins,a scientist might treat plants with

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

Question 36

Which statement about jasmonate is false?

A) It is a plant hormone.
B) Its production is stimulated by elicitors.
C) It is part of the signal transduction pathway.
D) It is part of the plant's "chemical warfare" defenses.
E) It triggers production of volatile compounds that attract predatory insects.

Question 37

For an R gene to confer resistance,an invading pathogen must have a corresponding

A) R gene.
B) tRNA.
C) T gene.
D) detector.
E) Avr gene.

Question 38

Plants produce alkaloid neurotoxins such as nicotine to deter herbivores.These chemicals can be classified as both

A) primary metabolites and constitutive defenses.
B) secondary metabolites and constitutive defenses.
C) primary metabolites and induced defenses.
D) secondary metabolites and induced defenses.
E) secondary metabolites and mechanical defenses.

Question 39

Which hypothetical treatment would likely enable an insect larva to resist canavanine?

A) Hormonal treatment to delay metamorphosis
B) Hormonal treatment to accelerate metamorphosis
C) RNA interference to stop production of improper proteins
D) Genetic engineering to add an enzyme enabling its tRNA to distinguish between arginine and canavanine
E) Genetic engineering to add an enzyme enabling its tRNA to distinguish between lecuine and canavanine

Question 40

Genetically engineering tobacco plants to increase their nicotine concentration would most likely result in plants with

A) greater resistance to herbivores.
B) less resistance to herbivores.
C) more jasmonic acid.
D) better nervous system function.
E) greater tolerance to insecticides.

Question 41

Which statement about the plant secondary metabolites used in "chemical warfare" against herbivores is false?

A) Many carry out basic plant functions.
B) They have a variety of effects on animals.
C) There are more than 10,000 known types.
D) They vary in size,but most are small molecules.
E) Some are produced by a single species,while others are produced by many different plants.

Question 42

An accumulation of the amino acid proline and other solutes enables plants to

A) become toxic to most herbivores.
B) carry out alcoholic fermentation.
C) avoid the toxic effects of sodium.
D) extract water from the soil by osmosis.
E) initiate a signaling pathway to close stomata.

Question 43

An accumulation of proline and secondary metabolites in vacuoles helps plants counteract which type of environmental stress?

A) Heat
B) Cold
C) Drought
D) Saturation
E) High heavy metal concentrations

Question 44

Considering the signal transduction pathway involved in induced defenses,what would be the most likely outcome if a mutation in JAZ interfered with its capacity to bind to jasmonate?

A) Production of protease inhibitors would decrease.
B) Elicitors would bind to receptors less readily.
C) Elicitors would bind to receptors more readily.
D) Production of protease inhibitors would increase.
E) Jasmonate production would decrease.

Question 45

Plants such as sorghum produce cyanide,a highly toxic defensive chemical.These plants avoid poisoning themselves by

A) dissolving the cyanide in waxes.
B) storing the cyanide in separate vacuoles.
C) storing the cyanide in the intercellular spaces.
D) modifying the cyanide so it is only toxic outside the plant cell.
E) storing the cyanide precursor separately from its activating enzyme.

Question 46

Which adaptation would not be useful to a plant living in a dry environment?

A) A deep taproot
B) Airborne roots
C) Fleshy leaves
D) Proline accumulation
E) A shallow but extensive root system

Question 47

Desert plants such as cacti can take up copious amounts of water quickly and use it slowly during long dry periods because of their

A) trichomes.
B) fleshy leaves.
C) pneumatophores.
D) shallow but extensive roots.
E) high concentrations of proline.

Question 48

Which of the following represents the correct chronological ordering of the events in the signaling pathway against herbivory?

A) Receptor-elicitor binding,binding of jasmonate to JAZ,traveling of jasmonate through plasmodesmata,increased expression of protease inhibitor
B) Receptor-elicitor binding,binding of jasmonate to JAZ,increased expression of protease inhibitor,traveling of jasmonate through plasmodesmata
C) Receptor-elicitor binding,traveling of jasmonate through plasmodesmata,binding of jasmonate to JAZ,increased expression of protease inhibitor
D) Traveling of jasmonate through plasmodesmata,receptor-elicitor binding,binding of jasmonate to JAZ,increased expression of protease inhibitor
E) Traveling of jasmonate through plasmodesmata,receptor-elicitor binding,increased expression of protease inhibitor,binding of jasmonate to JAZ

Question 49

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

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

Question 50

Which plant adaptation would be found in a water-saturated,rather than a dry,environment?

A) Spines
B) Fleshy leaves
C) Dense epidermal hairs
D) Pneumatophores
E) Stomata in sunken cavities

Question 51

Several plants,including the castor oil plant,defend themselves against herbivory by producing highly toxic water-soluble proteins called ricins.Proricin,consisting of A and B chains,is stored in vacuoles called protein bodies.It becomes active when an enzyme inside the protein body cleaves the A and B chains.This suggests that the castor oil plant is able to avoid self-poisoning by

A) compartmentalizing the ricins.
B) storing the ricins on the plant surface.
C) storing the ricins in the plasma membrane.
D) both compartmentalizing the ricins and storing them as precursors.
E) both storing the ricins in the plasma membrane and storing them as precursors.

Question 52

Laticifers in milkweed plants (Asclepias sp. )are storage areas for latex containing toxic defensive chemicals.Milkweeds are able to protect themselves from their own toxic chemicals by

A) storing the latex in tubelike laticifers that empty into xylem tubes.
B) storing the latex in tubelike laticifers that empty into phloem tubes.
C) storing the latex in tubelike laticifers that run along the veins.
D) only synthesizing chemicals to store in latex when they are needed.
E) allowing the latex to leak out when it begins to poison the plant.

Question 53

Xerophytes live in which type of environment?

A) Marsh
B) Desert
C) Temperate evergreen forest
D) Area with very cold temperatures
E) Area with high mercury concentration

Question 54

The evidence that some beetles cut veins of milkweeds to interrupt the flow of latex to other parts of the plant demonstrates that

A) laticifers are always effective as plant defenses.
B) laticifers are always ineffective as plant defenses.
C) these beetles have learned to bypass an effective plant defense.
D) these beetles are able to overcome the toxicity of chemicals in latex.
E) milkweeds are unable to protect themselves from their own poisons.

Question 55

A desert plant shedding its leaves during the dry season is engaged in

A) succulence.
B) drought avoidance.
C) drought hardening.
D) hyperaccumulation.
E) solute accumulation.

Question 56

Leaves of a plant may be damaged accidentally-for example,when an animal steps on them.In this situation,the plant does not mobilize its immune defenses;it only does so in case of herbivory.How does the plant tell the difference?

A) Herbivory lasts longer than accidental injury.
B) Herbivory is more damaging than accidental injury.
C) Herbivores release chemicals that mimic plant reactions.
D) Herbivores cause mechanical damage;accidental injury does not.
E) Herbivores release elicitors in their saliva,triggering plant reactions.

Question 57

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

A) vacuoles.
B) chloroplasts.
C) Golgi bodies.
D) cell membranes.
E) epidermal waxes.

Question 58

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

A) Desert
B) Salt marsh
C) Grazed field
D) Freshwater marsh
E) Recently mined area

Question 59

Plants in saturated environments such as mangrove swamps are most often subject to which environmental stressor?

A) Heat
B) Cold
C) High salinity
D) Slow growth rates
E) Low oxygen concentration

Question 60

A scientist is testing a variety of plant compounds to determine which,if any,have characteristics that would make them good natural insecticides.Which compound would best meet this requirement?

A) A pigment that provides color for flowers
B) A volatile compound that acts as an insect neurotoxin
C) A substance produced as a byproduct of respiration
D) A volatile compound that attracts pollinators
E) An essential oil with a pleasant odor that attracts insects

Question 61

Hyperaccumulators most likely evolved in areas having soils containing

A) excess water.
B) limited water.
C) limited nutrients.
D) high salt concentrations.
E) high heavy metal concentrations.

Question 62

Which statement about aerenchyma tissue is false?

A) It stores oxygen.
B) It stores water.
C) It aids in buoyancy.
D) It has a low metabolic rate.
E) It diffuses oxygen to the rest of plant.

Question 63

During freezing weather,a plant that lacks antifreeze proteins is likely to experience all of these conditions except

A) dehydration.
B) punctured organelles.
C) punctured cell membranes.
D) formation of ice crystals.
E) denaturation of proteins.

Question 64

A plant that lives in a desert and is a "drought avoider" most likely

A) has spines.
B) has trichomes.
C) is a succulent.
D) has periods of dormancy.
E) has stomatal crypts.

Question 65

Scientists working to produce a transgenic rice plant containing a fish gene that codes for an antifreeze protein are most likely trying to

A) determine if fish genes can survive in plants.
B) produce a rice plant that grows at colder temperatures.
C) produce a rice plant that speeds up the growth of ice crystals in freezing weather.
D) produce a rice plant that undergoes cold-hardening more quickly.
E) produce a rice plant that is more suitable for high temperature ranges.

Question 66

During drought stress in plants,a signaling pathway initiates the production of two types of substances: _______ to conserve water and maintain cell membrane integrity,and _______ to stabilize protein structure.

A) jasmonic acid;abscisic acid
B) abscisic acid;jasmonic acid
C) LEA proteins;abscisic acid
D) abscisic acid;LEA proteins
E) LEA proteins;jasmonic acid

Question 67

Which substance is upregulated in plants experiencing either drought stress or cold-hardening?

A) Tannins
B) Nicotine
C) Jasmonate
D) Canavanine
E) LEA proteins

Question 68

The pneumatophores of swamp plants are modified

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

Question 69

The ventilation system in a greenhouse malfunctions,causing the temperature to rise almost 7°C in a very short time.The plants begin to undergo heat shock,causing them to produce which type of protein?

A) Proline
B) Kinases
C) Nucleases
D) Antifreeze proteins
E) Chaperonins

Question 70

If the concentration of LEA proteins in a plant is decreasing,the plant is most likely experiencing

A) decreased drought stress.
B) decreased heat stress.
C) increased drought stress.
D) increased heat stress.
E) decreased heavy metal concentrations.

Question 71

Which type of stress is most likely to denature a plant's proteins?

A) High temperatures
B) Heavy metals
C) Low temperatures
D) Herbivores
E) High salt concentrations

Question 72

Recent research has identified the presence of LEA proteins in several groups of animals as well as in plants.In what type of environment do these animals most likely live?

A) Saline
B) Arctic
C) Desert
D) Swampy
E) Temperate

Question 73

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

A) growing deep taproots.
B) inhibiting ATP production.
C) producing oxygen from water.
D) diffusing oxygen through lenticels.
E) releasing the hormone abscisic acid.

Question 74

When plants suffer cold stress,but the temperature is still above freezing,which aspect of the plant cell is most subject to damage?

A) The ability to dissipate heat
B) The ability to form antifreeze proteins
C) The ability to form heat-shock proteins
D) The membrane's fluidity
E) The membrane's ability to contain substances

Question 75

A plant lives in a marshy environment where its roots are always submerged.Its leaf and stem tissues are most likely modified by the presence of

A) aerenchyma.
B) pneumatophores.
C) LEA proteins.
D) a thick cuticle.
E) additional stomata.

Question 76

Which biochemical aspects of plants and their cells are quickly compromised as a result of excessive drought?

A) Protein structure and membrane integrity
B) Protein structure and cellular respiration
C) Membrane integrity and cellular respiration
D) Abscisic acid production and stomatal closing
E) Abscisic acid production and chaperonin production

Question 77

The first hormone produced by a plant as part of an induced response to drought stress is

A) ethylene.
B) abscisic acid.
C) canavanine.
D) jasmonate.
E) heat shock protein.

Question 78

Some halophytic plants have salt glands that

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

Question 79

Which response to high temperatures is most analogous to the cold-hardening response to low temperatures?

A) The production of hairs
B) The growth of spines
C) The production of jasmonate
D) The production of chaperonins
E) The production of abscisic acid

Question 80

Most xerophytes adapt to dry conditions with the use of constitutive,rather than induced,mechanisms.The most likely reason is that constitutive mechanisms

A) are always present.
B) evolve more readily.
C) provide better protection.
D) are more energy-efficient.
E) do not require the use of energy.