Deck 41: Sensory Systems in Plants

Question 1

Which gaseous hormone stimulates the ripening of fruits?

A)abscisic acid
B)gibberellin
C)indoleacetic acid
D)ethylene
E)cytokinin

Answer 1

D

Question 2

The hormone _________ has a more pronounced role in stem elongation if auxin is also present.

A)ethylene
B)gibberellin
C)cytokinin
D)abscisic acid
E)brassinolide

Answer 2

B

Question 3

Which of the following traits does not apply to brassinosteroids?

A)They were first discovered in pollen.
B)They are released from the cell wall by enzymes secreted by pathogens.
C)Their functions overlap with those of auxins and gibberellins.
D)Their characteristics are similar to animal steroids.
E)They may have evolved before the evolutionary divergence of plants and animals.

Answer 3

B

Question 4

Rapid turgor pressure changes in specialized multicellular swellings called ____________ are associated with leaves that move in response to touch or light.

A)petioles
B)pulvini
C)stipules
D)pudicas
E)coleoptiles

Question 5

Which of the following statements about phytochrome is not true?

A)It exists in two interconvertible forms.
B)P_R absorbs red light.
C)P_FR is biologically inactive.
D)P_FR reverts to P_R in the dark.
E)Several versions of phytochrome exist with overlapping but distinctive functions.

Question 6

Which of the following statements about gravitropism is false?

A)Shoots exhibit negative gravitropism.
B)Amyloplasts play a role in perceiving gravity.
C)Gravitropic responses are evident at germination.
D)Ethylene is important in plants' responses to gravity.
E)In roots,the gravity-sensing cells are located in the root cap.

Question 7

________________ are complex carbohydrates that are released from plant cell walls and appear to regulate both pathogen responses and growth and development in some plants.

A)Brassinosteroids
B)Oligosaccharides
C)Cytokinins
D)Auxins
E)Glycoproteins

Question 8

________________ is directional growth responses of plants to a unidirectional source of light.

A)Gravitropism
B)Thigmotropism
C)Dormancy
D)Phototropism
E)Thermotropism

Question 9

The elongation of stems is stimulated by

A)auxin only.
B)gibberellin only.
C)ethylene only.
D)auxin and gibberellin.
E)auxin and ethylenE.

Question 10

Cytokinins are related to or derived from which purine base?

A)adenine
B)thymine
C)guanine
D)cytocine
E)uracil

Question 11

Which of these is not one of the steps that lead to a gravitropic response in plants?

A)Signals form in the cell that perceives the stimulus.
B)Differential cell elongation occurs.
C)Auxin accumulates unevenly on opposite sides of the stem or root,stimulating the bending in response to gravity.
D)Amyloplasts float upward inside the perceptive cells.
E)Hormone signals are transported away from the tips of the roots or shoots.

Question 12

Red light and phytochrome are involved in all of the following plant growth responses except

A)thigmotropic responses.
B)inhibition of seed germination.
C)elongation of etiolated shoots.
D)signals for overlapping distances between plants.
E)photomorphogenesis.

Question 13

If temperatures suddenly rise 5 to 10º C,__________ proteins are produced to help stabilize other proteins.

A)denatured
B)photosensitive
C)chilling
D)heat shock
E)oxidative

Question 14

Mature plants may become __________ in dry or cold seasons in order to survive long periods that are unfavorable for growth.

A)dormant
B)dehydrated
C)photoperiodic
D)thigmonastic
E)gravitropic

Question 15

Abscisic acid suppresses growth of buds and promotes

A)lengthening.
B)dormancy.
C)rolling.
D)color change.
E)development.

Question 16

The plant hormones known as ___________ are structurally similar to animal steroid hormones.

A)brassinosteroids
B)oligosaccharides
C)cytokinins
D)auxins
E)abscisic acids

Question 17

Which of the following is not one of the seven major kinds of plant hormones?

A)auxin
B)nitrogen oxide
C)cytokinin
D)gibberellin
E)ethylene

Question 18

Charles Darwin and his son experimented with which plant growth response?

A)gravitropism
B)circadian rhythms
C)phototropism
D)heat shock
E)thermotropism

Question 19

_______________ are chemical substances produced in small quantities in one part of an organism and then transported to another part of the organism,where they bring about physiological responses.

A)Glycoproteins
B)Photosynthates
C)Hormones
D)Heat shock proteins
E)Pulvini

Question 20

Which of the following statements about hormones is false?

A)They are chemical signals produced in the organism.
B)They are produced in small,often minute quantities.
C)They are produced in one part of the organism and transported to another.
D)Their effect is the same throughout the organism.
E)They can stimulate certain physiological processes while inhibiting others.

Question 21

The acid-growth hypothesis links

A)oligosaccharins to pH changes.
B)cytokinin to thigmonasty.
C)auxin to cell wall expansion.
D)gibberellin to root elongation.
E)ethylene to leaf abscission.

Question 22

What endogenous process helps plants to keep their movements and other responses synchronized with the environment?

A)purine monitoring
B)solar tracking
C)a circadian clock
D)auxin cycling
E)gravitropism

Question 23

Which of the following actions is not a major function of auxins?

A)inhibition of leaf abscission
B)promotion of seed germination
C)stimulation of the elongation of cells by acting on cell walls
D)stimulation of the formation of roots on cuttings
E)promotion of the activity of the vascular cambium

Question 24

Which naturally-occurring plant hormone has a major role in the phototropic response of plants?

A)auxin
B)gibberellin
C)abscisic acid
D)ethylene
E)2,4-D

Question 25

When Darwin covered the tip of a grass seedling with metal foil and then illuminated it from one side,what happened to the seedling?

A)It bent away from the directional light.
B)It did not respond to the directional light.
C)It grew toward the light,as expected.
D)It waved back and forth.
E)It wilted and died.

Question 26

Gibberellins were first identified in

A)rice.
B)apples.
C)bananas.
D)tomatoes.
E)grapes.

Question 27

A compound similar to auxin,2,4,5-trichlorophenoxyacetic acid (2,4,5-T),has been used

A)as a fertilizer for corn and wheat.
B)as a spray to promote flowering of pineapple.
C)as an organic substitute for chlorine bleach.
D)to detoxify the dangerous poison dioxin.
E)an herbicide for killing weeds and woody seedlings.

Question 28

Turgor movements in plants are responsible for all of the following actions except

A)reversible changes in water pressure within plant cells.
B)reduction of water loss from transpiration.
C)folding of leaflets in the Mimosa pudica plants.
D)flowers that open during the day and close at night.
E)inducing changes in the active form of phytochromE.

Question 29

The plant hormone that is functional as a gas is

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

Question 30

Cytokinins promote cell division and differentiation in plant tissues,but only in the presence of what other plant hormone?

A)auxin
B)ethylene
C)abscisic acid
D)gibberellin
E)oligosaccharin

Question 31

Which of the following statements about abscisic acid is false?

A)It is produced chiefly in mature green leaves and in fruits.
B)It stimulates the growth of dormant buds.
C)It promotes leaf senescence.
D)It plays an important role in controlling the opening and closing of stomata.
E)It plays a role in seed dormancy.

Question 32

Which of the following plant hormones promotes fruit ripening?

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

Question 33

During a viticulturist's presentation on growing and managing grapes,why did he state that it is imperative to encourage the grapevine's natural tendency for positive thigmotropism?

A)To encourage the vine's response to move toward the early morning light as opposed to the late afternoon sun.
B)To encourage the roots to grow deeper and spread out.
C)To encourage the grapes to retain their sugar for a longer period of time.
D)To encourage the twining stems to wrap around the supporting wires.
E)To encourage the self-pruning that is natural to grapevines.

Question 34

Coconut milk was an extremely useful additive in plant tissue culture because,in addition to amino acids,it contains

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

Question 35

Which of these is not true about gibberellins?

A)They are produced in the apical regions of shoots and roots.
B)They promote internode elongation.
C)They can be applied to certain dwarf mutants to restore normal growth and development.
D)They hasten seed germination.
E)They inhibit amylases and other hydrolytic enzymes in seeds.

Question 36

Ethylene plays a number of roles in plants,including all of the following except

A)retarding stem and root elongation.
B)hastening the ripening of fruits.
C)increasing the storage life of apples,bananas,and oranges.
D)accelerating the loss of damaged leaves and fruits.
E)retarding lateral bud growth.

Question 37

Which tropism is not correctly matched with its meaning?

A)phototropism-response to light
B)gravitropism-response to gravity
C)thigmotropism-response to touch
D)thermotropism-response to temperature
E)heliotropism-response to carbon dioxide

Question 38

One effect of auxin,which triggers the elongation of cells,is to affect cell walls by increasing their

A)permeability.
B)plasticity.
C)stiffness.
D)thickness.
E)water solubility.

Question 39

The directional growth response of plants to touch is called

A)phototropism.
B)gravitropism.
C)thigmotropism.
D)photoperiodism.
E)thermotropism.

Question 40

Which of the following is not a characteristics of cytokinins?

A)stimulate cell division
B)inhibit growth of lateral roots
C)related to or derived from adenine
D)help determine the course of tissue differentiation
E)accelerate leaf aging

Question 41

Choose the letter of the best match from the following:
A.abscisic acid
B.auxin
C.ethylene
D.cytokinin
E.gibberellin
A chemical derivative of adenine.

Question 42

Removing the apical bud of a stem usually results in

A)faster flowering.
B)a bushier plant.
C)stunted growth.
D)leaf abscission.
E)starch accumulation.

Question 43

What happens when coleoptiles are illuminated with directional light from the side instead of from directly overhead?

A)More auxin is produced.
B)Less auxin is produced.
C)Auxin is transported away from the lighted side.
D)Auxin is transported toward the lighted side.
E)Auxin receptors are activated.

Question 44

Before ARF transcription factors can trigger auxin-induced gene expression,what must happen?

A)Auxin binds to ubiquitin,a degradation tag.
B)Auxin degrades Aux/IAA proteins which repress ARF transcription factors.
C)Auxin binds to TIR1,an auxin receptor.
D)Auxin must bind to the ARF transcription factor.
E)Ubiquitin must destroy TIR1 to release Aux/IAA proteins.

Question 45

All of the following are uses of synthetic auxins,such as NAA and IBA,in agriculture and horticulture except

A)to promote flowering and fruiting in pineapples.
B)to prevent fruit drop.
C)to induce formation of roots in plant cuttings.
D)to prevent leaf and fruit abscission.
E)to produce bushier plants.

Question 46

Most dwarf plants are mutants that

A)produce too much gibberellin.
B)cannot produce auxin.
C)produce too much cytokinin.
D)have defective auxin receptors.
E)cannot produce gibberellin.

Question 47

Auxin from the apical bud

A)stimulates the growth of lateral buds.
B)inhibits the transport of sucrose towards the roots.
C)stimulates the growth of leaves.
D)inhibits the growth of lateral buds.
E)inhibits tip elongation.

Question 48

Several scientists,including Charles and Francis Darwin,Frits Went and others,demonstrated that auxins caused stems to bend toward light in a series of elaborate experiments.Went was the researcher who finally determined that bending of the stem toward light was a result of which mechanism?

A)Light caused a reduction in auxin concentration and a reduction in stem elongation on the lighted side of the plant stem,and thus a bending in the direction of the light.
B)The transport of auxin to the shaded side of the plant stem stimulated stem elongation and a bending in the direction of the light.
C)Auxin concentration was equal on both sides (lighted and shaded)of the stem;however,the apical meristem responded to the presence of light.
D)A combination of positive phototropism and a negative gravitropism.
E)The stems actually were responding to the agar blocks that had been used in the experiments.

Question 49

Skototropism is an unusual tropism based on growth toward darkness rather than toward light as in phototropism.Which of these is an example?

A)plants growing in the shade of another plant
B)germinating seedlings growing through the soil
C)root tips growing in the soil
D)vine seedlings on the forest floor searching for tree trunks to climb
E)night-blooming flowers

Question 50

Which of the following statements about phototropisms is false?

A)They mostly occur through a response to green light and an estradiol receptor.
B)They include bending of plant stems toward light.
C)Occasionally roots exhibit a weak negative phototropic response.
D)They help plants position themselves better toward available light.
E)They can influence the development of plant organs.

Question 51

When one plant is shaded by another,why is the ratio of far-red to red light increased compared to an unshaded plant?

A)Phytochrome in the taller plant absorbs most of the red light.
B)Auxin absorbs mostly far-red light.
C)As light passes through the leaves of the taller plant,most of the red light is absorbed by chlorophyll.
D)Far-red light mostly reflects off the surface of the soil while red light is mostly absorbeD.
E)Shade is enriched in far-red wavelengths of light.

Question 52

A scientist is investigating a hormone response in rose bush stems.The apical meristems of the main stems were removed to allow the lateral buds to develop.What hormone will induce the development of lateral buds once the apical meristems are removed?

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

Question 53

What color of light triggers the phototropic response in coleoptiles?

A)blue
B)green
C)yellow
D)red
E)far-red

Question 54

When gibberellin binds to its receptor,what happens to activate the gibberellin-dependent transcription factor GA-TRXN?

A)Ethylene is released.
B)A ubiquitin tag is used to degrade the GA-TRXN inhibitor.
C)A DELLA protein is degraded,freeing the GA-TRXN.
D)A DELLA protein is attached to GA-TRXN to activate it.
E)The gibberellin is transferred to an alternate binding sitE.

Question 55

Directional,light-triggered plant development is known as

A)thigmotropism.
B)phototropism.
C)thigmonasty.
D)photomorphogenesis.
E)acid-growth movement.

Question 56

In some genetically engineered tomatoes,fruit ripening was delayed by crippling the gene that produces which hormone?

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

Question 57

A viticulturist wants to grow larger grapes.A plant physiologist suggests which specific hormone treatment to increase the internode lengths of the plants?

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

Question 58

In Arabidopsis plants,about 10% of its genome is devoted to processes tied to which molecule?

A)auxin
B)ubiquitin
C)rubisco
D)phytochrome
E)gibberellins

Question 59

A plant physiologist treats a leaf with abscisic acid and observes that the stomata close.What happened inside the guard cells during the experiment?

A)Abscisic acid influences the movement of sodium ions out of the guard cells.
B)Abscisic acid influences the movement of potassium ions out of the guard cells.
C)Abscisic acid binds carbon dioxide and causes carbonate crystals to block the stomatal opening.
D)Abscisic acid binds with auxins and induces water molecules to exit the guard cells.
E)Abscisic acid causes the guard cells to become more turgid.

Question 60

How do nastic movements differ from tropisms?

A)Nastic movements are slower than tropisms.
B)Nastic movements only occur in the dark.
C)Tropisms are directional responses to directional stimuli;nastic movements are the same regardless of the direction of the stimulus.
D)Nastic movements happen after a stimulus,tropisms happen during a stimulus.
E)Nastic movements are not reversiblE.

Question 61

Choose the letter of the best match from the following:
A.abscisic acid
B.auxin
C.ethylene
D.cytokinin
E.gibberellin
Influential in the opening and closing of stomata.

Question 62

Choose the letter of the best match from the following:
A.abscisic acid
B.auxin
C.ethylene
D.cytokinin
E.gibberellin
Its defoliant effects were first noticed when it leaked from gas lights;later found to be produced by plants themselves.