Deck 39: Plant Defense Responses

Question 1

Tannins are chemicals that help plants repel invaders by

A)over-stimulating the predator.
B)sedating the predator.
C)binding to proteins and thereby disrupting the predator's digestion.
D)injuring the external covering of the predator's body.

Answer 1

C

Question 2

The steps in the pathogen-specific response do not include

A)responding to the pathogen.
B)development of antibodies.
C)recognizing the pathogen.
D)triggering the hypersensitive response.

Answer 2

B

Question 3

How does systemin cause the activation of the wound response in tomato plants?

A)It binds directly to jasmonic acid.
B)It directly signals gene expression.
C)It induces the production of tannins.
D)It induces a jasmonic acid signaling pathway in certain cells.

Answer 3

D

Question 4

Nonnative plant invaders, such as the alfalfa plant bug, are extremely invasive and hard to control because

A)they arrive in new locations where natural predators are not present.
B)they tap into the xylem of a plant while seeking carbohydrates.
C)they cause the plants' axillary buds to grow out.
D)their populations evolve faster than the plants they attack.

Question 5

Which of the following statements about plant toxins against herbivores is false?

A)The toxin may be kept in a membrane-bound structure to keep it from harming the plant.
B)The toxin may not be toxic unless it is metabolized in the intestine of a herbivore.
C)The toxin may have also have a bad taste.
D)Even a little bit of the toxin will be deadly.

Question 6

Viruses travel through animals mainly by lysing cells and then spreading to other cells.Plant cells are not easily lysed.If a pathogen enters a plant cell and does not initiate a hypersensitive response, what is the most likely way the virus would spread to other plant cells?

A)Through the chloroplasts.
B)Directly through the cell wall.
C)Through the central vacuole.
D)Through the plasmodesmata.

Question 7

Systemic acquired resistance is

A)a broad-ranging resistance that lasts for a period of days.
B)the same as the human immune response.
C)a response whereby antibodies recognize specific antigens.
D)a response that occurs when the hypersensitive response fails.

Question 8

Which of the following steps is not one of the phases of a fungal invasion of a plant?

A)Windblown fungal spores land on plant leaves.
B)Hyphae grow through cell walls and press against the cell membrane.
C)Fungal DNA is replicated by the plant cells.
D)Hyphae differentiate into specialized structures called haustoria.

Question 9

Systemin can correctly be described as a(n)

A)peptide.
B)apoplast.
C)receptor.
D)leaf lipid.

Question 10

Evidence that black walnut trees exhibit allelopathy includes

A)the lack of vegetation growing under black walnut trees.
B)the death of hornworms that try to eat black walnut leaves.
C)the symbiotic relationship the trees have with fungi.
D)the ants that protect the trees from herbivory.

Question 11

Phytoestrogens are steroid-like chemicals that are derived from soy.One of their characteristics is that they are able to

A)paralyze nerve endings.
B)bind to the human estrogen receptor.
C)cause estrogen breakdown within human cells.
D)increase the rate of prostate cancer in men.

Question 12

Parasitoid wasps are sometimes involved in a plant's defensive response.In what way are the wasps helpful to the plant?

A)The wasps respond to a chemical the plant gives off when wounded, and the wasps lay their eggs on the caterpillar that wounded the plant.
B)The wasps live in hollow thorns of the plants, and attack the plants' predators.
C)The wasps stimulate the production of alkaloids the plants use for defense.
D)The wasps enhance the plants' hypersensitive response.

Question 13

Plants such as peppermint and sage contain oils.What is the function of these oils?

A)They help keep the plant from drying out.
B)They help repel insects.
C)They keep other plants from germinating nearby.
D)They prevent fungal infection.

Question 14

____________ occurs when a chemical signal secreted by the roots of one plant blocks the germination of nearby seeds or inhibits the growth of a neighboring plant.

A)Nodulation
B)Etiolation
C)Reduction
D)Allelopathy

Question 15

The activation of proteinase inhibitor genes occurs

A)in the cytoplasm of the affected cells.
B)on the plasma membrane of the affected cells.
C)in the nucleus of the affected cells.
D)before the systemin moves through the phloem of the plant.

Question 16

Which of the following chemicals is a signal that induces systemic acquired resistance?

A)salicylic acid
B)brassinosteroids
C)systemin
D)avr

Question 17

Which of the following methods do fungi use in order to penetrate the initial layer of a plant's defenses?

A)mechanical bridging
B)sharp mouthparts
C)entry through stomates
D)secretion of phospholipids to dissolve the cuticle The phases of fungal infection are discussed in Section 39.1.

Question 18

Which of the following plant secondary metabolites is used as an antimalarial drug?

A)morphine
B)taxol
C)genistein
D)quinine

Question 19

Which of the following statements about the pathogen-specific response is true?

A)The pathways involved always trigger the hypersensitive response.
B)The pathogen is recognized by its avr gene product.
C)There is never a gene-for-gene response.
D)If the R gene product is not triggered, no disease will occur.

Question 20

The series of metabolic events that occurs within tomato plants in response to wounding is

A)a systemic response.
B)a waterfall effect.
C)the hypersensitive response.
D)a pathogen-specific response.

Question 21

Which common crop may contain traces of hormone-like substances that may affect human health?

A)corn
B)wheat
C)peanuts
D)soybean

Question 22

What is the main difference between plant defense mechanisms that use secondary chemical metabolites versus plant defense mechanisms that use a systemic response?

A)The metabolites are not as lethal as the systemic response.
B)The metabolites are present at all times, and the systemic response must be induced.
C)The metabolites can only help in defense against insects, not against other plants.
D)The metabolites are toxic to the plants that produce them, the systemic response is safer.

Question 23

Cyanogenic glycosides, which break down into cyanide, are toxic to cells because they inhibit the function of which organelle(s)?

A)Golgi apparatus
B)Ribosome
C)Nucleolus
D)Mitochondria

Question 24

Many plants are filled with toxins that kill or deter herbivores.Many plants sequester these compounds within the cell.Where in the plant cell are these toxic substances most likely stored?

A)Central vacuole
B)Mitochondria
C)The stroma
D)Amyloplasts

Question 25

If a bacterium containing a mutation in the avirulence gene lands on a plant that has the corresponding R gene, the bacterium may not initiate rapid cell death in the plant.

Question 26

A nematode that has parasitized a plant has breached the cutin layer of the epidermis.

Question 27

The plant alkaloid ricin is nontoxic inside castor beans, but becomes active when digested by an animal.The toxic form of ricin kills by

A)inactivating the animal's immune system.
B)over stimulating the animal's heart rate.
C)inactivating ribosomes needed for translation.
D)binding to RNA polymerase.

Question 28

Systemic response occurs when plants exhibit generalized defense responses in organs distant from the wound.

Question 29

Which category of plant second metabolites includes stimulants like caffeine, nicotine, and cocaine?

A)tannins
B)alkaloids
C)phenolics
D)cyanogenic glycosides

Question 30

Using biotechnology, plant breeders attempt to find and incorporate specific resistance genes into plants that lack them.Once a plant has been given a resistance gene, it will have indefinite protection from the associated pathogen.

Question 31

A patient who requires repeated dosing with strong analgesics over a period of more than a few days might be prescribed which of the following secondary plant metabolites?

A)Genistein
B)Morphine
C)Quinine
D)Taxol

Question 32

Parasitic fungi will usually attack a plant through stomata on the root surface.

Question 33

Taxol, a secondary metabolite from the bark of the Pacific yew tree, is used as a treatment for

A)diabetes.
B)breast cancer.
C)indigestion.
D)headaches.

Question 34

Treating a plant with a fungicide could interfere with the plant's uptake of nitrogen.

Question 35

A plant has a mutation in the gene that codes for systemin.What is the likely consequence of this mutation?

A)The plant will have a stronger than normal wound response.
B)The mutated form of systemin would be recognized as a pathogen and a hypersensitive response will be initiated.
C)The levels of jasmonic acid will build inside the cell creating a toxic environment.
D)Systemin receptors will not be activated and proteinase inhibitor will not be transcribed.

Question 36

Why don't ants that protect the Acacia tree scare off bees trying to pollinate the tree's flowers?

A)They can't climb to the tops of the tree.
B)The bees are too big.
C)The bees fly in and out quickly.
D)The open flowers contain a chemical that is an ant deterrent.