Deck 46: Plant Responses to the Environment

Question 1

The synthetic herbicide 2,4- D is actually a(n)

A) florigen.
B) gibberellin.
C) ethylene gas.
D) cytokinin.
E) auxin.

Answer 1

E

Question 2

Why do bananas in a bag ripen so much faster than bananas on a counter top?

A) Auxins are present in low concentrations in the bag because sunlight stimulates the production of this hormone.
B) Abscisic acid, produced by the fruit, is trapped in the bag.
C) Ethylene, produced by the fruit, is trapped in the bag.
D) Cytokinins are present in low concentrations in the bag because sunlight stimulates the production of this hormone.
E) The bag holds in more moisture.

Answer 2

C

Question 3

The hormone was named after the fungus that causes "foolish seedling" disease in rice.

A) cytokinin
B) gibberellin
C) ethylene
D) auxin
E) florigen

Answer 3

B

Question 4

If you want to keep cut flowers fresh, treat them with

A) cytokinin.
B) ethylene.
C) abscisic acid.
D) auxin.
E) gibberellin.

Question 5

Gravitropism is a plant's

A) response to stress- inducing situations.
B) ability to form an abscission layer, so that the fruits and leaves fall from the plant.
C) directional response to gravity.
D) ability to grow only upward.
E) apical dominance.

Question 6

Seed germination is stimulated by

A) cytokinin.
B) abscisic acid.
C) florigen.
D) ethylene.
E) gibberellin.

Question 7

Which of these hormones helps plants tolerate drought and cold?

A) Ethylene
B) Gibberellin
C) Cytokinin
D) Auxin
E) Abscisic acid

Question 8

In 2007, research confirmed the existence of hormones that control the timing of flowering. These hormones are called

A) auxins.
B) florigens.
C) abscisic acids.
D) ethylenes.
E) cytokinins.

Question 9

Why does removing an overripe, mushy apple from a container of otherwise good apples help preserve the good apples?

A) Chemicals in the overripe apple stimulate the conversion of sugar to starch in the good apples.
B) Gibberellins help preserve the good apples.
C) Ethylene production in the good apples is inhibited by the lack of ethylene production in the overripe apple.
D) The production of cytokinins is inhibited in the remaining good apples.
E) The overripe apple makes ethylene gas, which can cause the good apples to ripen more quickly than usual.

Question 10

maintains seed dormancy, and ends seed dormancy by stimulating enzymes that break down the food reserves of the seed to fuel seedling growth.

A) Abscisic acid; ethylene
B) Auxin; cytokinin
C) Cytokinin; auxin
D) Gibberellin; abscisic acid
E) Abscisic acid; gibberellin

Question 11

How a plant cell responds to a hormone depends on the

A) presence of other plant cells nearby.
B) "shelf life" of the hormone.
C) cell that secretes the hormone.
D) concentration of the hormone.
E) amount of available sunlight.

Question 12

A plant's tendency to grow toward a source of light is called

A) phototropism.
B) lumitropism.
C) gravitropism.
D) amylotropism.
E) thigmotropism.

Question 13

How is the carnivorous plant lifestyle suited for an existence in bogs?

A) Bogs contain rich populations of nitrogen- fixing bacteria, which provide nitrogen to the plants.
B) Bogs contain many soil- based proteins, which are a good source of nitrogen.
C) Bogs are naturally high in nitrogen, which favors the carnivorous plant lifestyle.
D) The lack of nitrogen in bogs selects for the carnivorous plant lifestyle of ingesting and digesting animals for nitrogen.

Question 14

A scientist who claims to have discovered a new plant hormone must demonstrate that this compound is

A) produced in large amounts.
B) made from cell proteins.
C) formed in one part of the plant but has an effect in a different part.
D) needed by the plant as a major source of energy.
E) capable of stimulating differentiated cells to form meristem tissue.

Question 15

Tomatoes that are planted upside down still grow upright, displaying

A) phototropism.
B) lumitropism.
C) gravitropism.
D) amylotropism.
E) thigmotropism.

Question 16

After seeds were planted, some of the seedlings did not emerge from the soil. Is it possible they did not grow because some of the seeds were planted upside down?

A) Yes; if the seed was oriented so that the embryonic shoot pointed down, it would grow in that direction because sunlight doesn't reach it.
B) Yes; after seeds are planted, water and settling of the soil may cause them to shift in their orientation.
C) No; gibberellins and abscisic acid, in balanced concentrations, cause shoots to grow away from gravity.
D) No; sunlight penetrates soil to the depth of seeds and shoots grow toward the sunlight.
E) No; auxins in the shoots cause curvature away from gravity.

Question 17

triggers the formation of weak- celled abscission layers in leaves and fruits, allowing them to drop off at appropriate times during the year.

A) Cytokinin
B) Auxin
C) Abscisic acid
D) Ethylene
E) Gibberellin

Question 18

Pea plant tendrils wrapping around a string demonstrate

A) phototropism.
B) lumitropism.
C) gravitropism.
D) amylotropism.
E) thigmotropism.

Question 19

A botanist who wants to stimulate flower formation in response to light cues could treat the plants with

A) florigen.
B) auxin.
C) abscisic acid.
D) cytokinin.
E) ethylene.

Question 20

Roots grow downward and shoots grow upward due to

A) auxin.
B) cytokinin.
C) ethylene.
D) gibberellin.
E) abscisic acid.

Question 21

Suppose you have some seeds that refuse to germinate when placed in moist soil. What could you do to encourage the seeds to germinate?

A) Put them in direct sunlight.
B) Boil them.
C) Treat them with auxin.
D) Treat them with abscisic acid.
E) Treat them with gibberellin.

Question 22

Most scientists believe that the lateral buds farthest from the top of a tree are the least inhibited from sprouting because they

A) receive the most cytokinins from the roots.
B) produce gibberellins.
C) receive the least light.
D) are the most affected by gravity.
E) are shaded by the top of the tree.

Question 23

Abscisic acid enforces dormancy of seeds by

A) activating gibberellin.
B) waterproofing the seed coat.
C) binding to the molecule ATP.
D) preventing the development of the embryo and completion of the lifecycle.
E) preventing endosperm development.

Question 24

A species- specific ratio of produced in the apical meristem and _ produced in the root tips maintains a balance between shoot and root growth.

A) abscisic acid; ethylene
B) auxins; cytokinins
C) gibberellins; abscisic acid
D) cytokinins; auxins
E) abscisic acid; gibberellins

Question 25

What causes the "leaf drop" that occurs in woody plants in preparation for winter dormancy?

A) Inhibition of gibberellin
B) Opened stomata
C) Increased chlorophyll development
D) Increased ethylene production
E) Suppressed auxin production

Question 26

The relative sizes of roots and shoots are regulated by interactions between

A) gibberellins and abscisic acid.
B) auxins and cytokinins.
C) cytokinins and ethylene.
D) ethylene and abscisic acid.
E) abscisic acid and cytokinins.

Question 27

Elongation of cells in stems is promoted by

A) cytokinins and abscisic acid.
B) abscisic acid and ethylene.
C) enzymes and phytochromes.
D) ethylene and cytokinins.
E) auxins and gibberellins.

Question 28

Auxin

A) promotes phototropism.
B) stimulates flowering.
C) promotes cell division.
D) causes the development of an abscission layer.
E) inhibits stem elongation.

Question 29

What will happen to a long- day plant, such as spinach, if the light- dark pattern is interrupted by a flash of light for several days in a row during the spring?

A) Nothing will happen; growth and development will continue as normal.
B) The plants will be delayed in flowering.
C) The plants won't flower that season.
D) The plants are tricked into flowering earlier than usual.

Question 30

Which of these hormones causes cell elongation, promotes apical dominance, and stimulates root branching?

A) Gibberellin
B) Ethylene
C) Cytokinin
D) Abscisic acid
E) Auxin

Question 31

When auxin accumulates on the lower side of the root of a germinating seed, it

A) increases cell elongation on the lower side of the root
B) decreases the use of energy by the cells in the root.
C) has no effect on the root; it affects only the developing shoot.
D) increases the use of energy by the cells in the root.
E) decreases cell elongation on the lower side of the root.

Question 32

induces dormancy in seeds and buds and causes stomata to close.

A) Gibberellin
B) Cytokinin
C) Ethylene
D) Auxin
E) Abscisic acid

Question 33

The two hormones involved in seed germination and seed dormancy are

A) auxin and ethylene.
B) cytokinin and auxin.
C) abscisic acid and gibberellin.
D) gibberellin and auxin.
E) ethylene and cytokinin.

Question 34

If you were running a tree nursery and wanted to keep your trees dormant until the customer could plant them, which hormone would you spray on the trees?

A) Cytokinin
B) Ethylene
C) Abscisic acid
D) Gibberellin
E) Auxin

Question 35

To encourage the formation of well- developed, heavily branched roots, you should treat cuttings with

A) gibberellin.
B) abscisic acid.
C) auxin.
D) ethylene.

Question 36

When auxin accumulates on the lower side of the shoot of a germinating seed, it

A) decreases cell elongation on the lower side of the shoot.
B) decreases the use of energy by the cells in the shoot.
C) increases the use of energy by the cells in the shoot.
D) has no effect on the shoot; it affects only the developing root.
E) increases cell elongation on the lower side of the shoot.

Question 37

Ethylene

A) promotes leaf and fruit drop.
B) causes phototropism.
C) promotes gravitropism.
D) stimulates seed germination.
E) prevents leaf senescence.

Question 38

Most scientists believe that the lateral buds nearest the top of a tree are most inhibited from sprouting because they

A) produce gibberellins.
B) are the most affected by gravity.
C) receive the most auxin from the apical bud.
D) are most exposed to the light.
E) are shaded by the apical bud and the top of the tree.

Question 39

Placing a ripe apple in a bag of green bananas will cause the bananas to ripen quickly. This is because the apple

A) releases heat.
B) absorbs cytokinin.
C) produces ethylene gas.
D) forms digestive enzymes.
E) makes auxin.

Question 40

Cutting a hedge with a trimmer stimulates it to become bushy because

A) removing the apical meristems makes more auxin, which stimulates lateral branch buds to grow.
B) removing the lateral buds results in apical dominance under the influence of cytokinins.
C) removing the apical meristems makes less ethylene, which stimulates lateral branches to grow.
D) removing the apical meristems results in less auxin, which results in more lateral branch growth.

Question 41

Leaves of the Venus flytrap and other sensitive plants move quickly due to

A) reduced permeability to potassium ions.
B) muscle- like plant cells called myophytes.
C) an electrical stimulus and rapid diffusion of ions out of motor cells.
D) hormones that cause plant cell movement.

Question 42

plants bloom only when the duration of uninterrupted darkness is shorter than a critical length.

A) Short- day
B) Phytochrome- system
C) Neutral- day
D) Gibberellin- regulated
E) Long- day

Question 43

If a plant is living under conditions that limit root growth, shoot growth is

A) limited as well, due to less cytokinin being produced by the root.
B) unaffected by the amount of root growth.
C) stimulated, due to less cytokinin being produced by the root.
D) stimulated, due to more auxin being produced by the apical meristem.
E) limited as well, due to more auxin being produced by the apical meristem.

Question 44

Some plants under attack by insects can communicate this information to other parts of the same plant and to nearby plants via

A) low- frequency sound waves.
B) the release of chemicals into their roots.
C) vibrations in their roots.
D) the release of chemicals into the air.

Question 45

If a storm breaks off the top of a tree, within a year or two, one of the lower branches will grow upward and become the new tree top, while inhibiting other branches from doing the same. This is an example of

A) the presence of cytokinins.
B) apical dominance.
C) the formation of an abscission layer.
D) the influence of ethylene.
E) phytochrome inhibition.

Question 46

At night, when little red light is available to the plants in an area, what occurs?

A) Pr stimulates flowering.
B) Pr is converted to Pfr.
C) Pfr is converted to Pr.
D) Pr and Pfr are both destroyed.
E) Pr and Pfr are both formed from inactive phytochrome.

Question 47

The phytochrome that is active and absorbs far- red light is

A) Pfr.
B) Pe.
C) Pa.
D) Pr.

Question 48

A new type of strawberry plant produces fruit in the late spring, throughout the summer, and into the fall. It is a(n) plant.

A) day- neutral
B) long- day
C) short- day
D) indeterminate- day
E) night- determinate

Question 49

Plants that flower in the United States only in the early spring (when nights are long) are _ _ plants.

A) day- neutral
B) long- day
C) short- day
D) indeterminate- day
E) night- determinate

Question 50

What caterpillar saliva- based chemical stimulates a corn plant to release an alarm signal?

A) Volicitin
B) Salicylic acid
C) Methyl salicylate
D) Florigen
E) Salicin

Question 51

Willow trees and many other plants produce , from which aspirin is made.

A) nicotine
B) salicylic acid
C) acetic acid
D) acetaminophen
E) volantin

Question 52

The process of aging is called

A) senescence.
B) abscission.
C) elongation.
D) maturation.
E) death.

Question 53

What happens to phytochromes after several days of dark, rainy weather?

A) Pr absorbs darkness and converts to Pfr.
B) Pr stimulates flowering.
C) Pr and Pfr become unstable and both are destroyed.
D) Pr and Pfr are both formed from inactive phytochrome.
E) Pfr spontaneously reverts to Pr.

Question 54

The phytochrome Pr

A) is the active form of Pfr.
B) is inactive and absorbs red light.
C) is very unstable.
D) absorbs far- red light.

Question 55

Which pigment is responsible for the phototropism responses of plants?

A) Phytochrome
B) Ethylene
C) Chlorophyll
D) Auxin
E) Xanthophyll

Question 56

Short- day plants flower only if

A) the duration of uninterrupted darkness is longer than some species- specific length.
B) their phytochrome- mediated responses are inhibited.
C) they are in the shade.
D) abscisic acid is available.

Question 57

Plants that flower in the United States in July (when nights are short) are plants.

A) day- neutral
B) long- day
C) short- day
D) indeterminate- day
E) night- determinate

Question 58

Senescence in plants usually involves

A) apical dominance.
B) the presence of cytokinins.
C) the development of photosynthetic enzymes.
D) the formation of an abscission layer.
E) shade from other plants.

Question 59

Which environmental factor is most significant for flowering?

A) Water availability
B) Day length
C) Light intensity
D) Temperature
E) Nitrogen availability

Question 60

Which of the following is TRUE of the relationship between the phytochrome system and the biological clock of plants?

A) The phytochrome system detects light and resets the biological clock.
B) The phytochrome system manufactures special cells that control the biological clock.
C) The biological clock detects light and sends the information to the phytochrome system.
D) The phytochrome system serves as the biological clock for plants.
E) There is no relationship between the phytochrome system and the biological clock.

Question 61

When a peach blossom is pollinated, auxin and/or _ stimulates the development of fruit from the ovary.

Question 62

Cytokinins cause most of their responses in plants by stimulating cell .

Question 63

The only plant hormone that is a gas is cytokinin.

Question 64

In seeds from northern areas, what plant hormone often needs to be removed to get them to germinate, and how can it be removed?

Question 65

In the late winter, as seeds prepare to germinate, the levels of in seeds should be declining as the levels of are increasing.

Question 66

Venus flytraps catch insects in order to supplement their input of

A) phosphorus.
B) potassium.
C) nitrogen.
D) magnesium.
E) meat.

Question 67

Defend this statement: Plants are just as capable of responding to their environment as are animals.

Question 68

Vibrations from an insect trapped inside a carnivorous sundew and thrashing around to escape stimulate the sundew's response. What happens next?

A) The sundew's leaves snap shut and their spiked edges mesh, trapping the insect.
B) An electrical shock kills the insect.
C) Thigmotropism is activated, and it kills the insect.
D) The plant secretes a cocktail of digestive enzymes that rapidly breaks down the insect's body.

Question 69

Auxins are used in rooting powders to encourage the formation of well- branched roots.

Question 70

Plants, as prey, can't run away from their predators, but they can defend themselves. Is the predatory nature of Venus flytraps a defense mechanism, or does it serve some other purpose?

Question 71

A Native American tradition uses a "tea" made by soaking willow bark in water as a pain- reliever. Does it work? Why?

Question 72

Radish plants under insect attack

A) rapidly fold their petioles together.
B) produce the defensive toxin nicotine.
C) produce bitter chemicals and grow spines on their leaves.
D) release salicin, which is converted to salicylic acid within the insect.

Question 73

Ripening fruits are attached firmly to their trees, but once they are mature, the trees must release them. How does this happen?

Question 74

How do auxin and cytokinin interact to affect the shape and growth of a plant?

Question 75

Corn plants release chemicals that attract a parasitic wasp. The wasp, in turn, protects the corn plants from destruction by

A) stinging bees.
B) too dry soils.
C) caterpillars.
D) root worms.
E) other wasps.

Question 76

Why can flowers be brought "into bloom" out of season by changing the duration of light and darkness?

Question 77

Plants are able to measure the length of the night using the system.

Question 78

Shoots grow up and roots grow down due to thigmotropism.

Question 79

What kinds of hormonal changes occur as trees prepare for winter dormancy?

Question 80

If a coleus plant becomes tall and spindly, what can you do to encourage it to develop lateral branches, so that it becomes bushier?