Deck 39: Sensory Systems in Plants

Question 1

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

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

Answer 1

C

Question 2

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

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

Answer 2

D

Question 3

Which cell structure is most likely responsible for sensing gravity?

A)central vacuole
B)Golgi apparatus
C)chloroplast
D)amyloplast
E)apical meristem

Answer 3

D

Question 4

A plant sustains pathogen-induced damage to one of its cell walls.A gene-for-gene response soon follows and the tissue surrounding the injury soon dies.Which signaling molecules facilitated this response?

A)Oligosaccharins
B)Ethylene
C)Gibberellins
D)Auxins
E)Abscisic acid

Question 5

Climbing plants,such as vines,rely on touch to navigate and develop tendrils that coil around objects they encounter.Roots also rely on touch to navigate their way through the soil.When roots come into contact with an object,they generally grow in a direction away from the object.Based on this information,which of the following statements is true?

A)Both tendrils and roots are displaying thigmonastic responses to an object in the environment.
B)The tendrils are displaying a thigmonastic response while the roots are displaying a thigmotropic response.
C)The tendrils are displaying a positive thigmotropic response while the roots are displaying a negative thigmotropic response.
D)The tendrils are displaying a thigmotropic response while the roots are displaying a thigmonastic response.
E)The tendrils are displaying a negative thigmotropic response while the roots are displaying a positive thigmotropic response.

Question 6

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 7

When seeds are removed from strawberries,fruit growth is stopped.This suggests the seeds contain which of the following hormones?

A)ethylene
B)auxin
C)strigolactones
D)oligosaccharides
E)gibberellins

Question 8

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 9

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 10

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 11

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 12

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 13

Abscisic acid (ABA)is synthesized in the roots in response to decreased soil water potential.ABA then translocates to the leaves,where it rapidly alters the osmotic potential of guard cells.What effect would this have on the stomata and the process of transpiration?

A)The stomata would open thereby increasing the rate of transpiration.
B)The stomata would open thereby decreasing the rate of transpiration.
C)The stomata would close thereby decreasing the rate of transpiration.
D)The stomata would close thereby increasing the rate of transpiration.
E)The change in the stomata would have no effect on the rate of transpiration.

Question 14

While touring the ancient Egypt exhibit at the local history museum,you learn that ancient Egyptians would slash figs in order to stimulate ripening.Based on your knowledge of plant hormones you hypothesize that wounding the figs must release

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

Question 15

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 woody seedlings and dicot weeds.

Question 16

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 17

Gibberellins affect many processes in plants.In seeds embryos,gibberellins are believed to signal hydrolysis of the stored food reserves through inducing the synthesis of the enzyme α-amylase.Which food source are gibberellins targeting with the release of α-amylase?

A)omega-3 fatty acids
B)starch
C)glycogen
D)fructose
E)protein

Question 18

________ 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 19

The plant hormones known as ________ may have an evolutionary origin in the common ancestor to both plants and animals.

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

Question 20

While touring a farm,the farmer tells you that she uses cytokinin to increase crop productivity.But,from biology class you know that cytokinin alone has no effect on parenchyma cells.What other substance is the farmer most likely using in conjunction with cytokinin?

A)auxin
B)abscisic acid
C)strigolactones
D)ethylene
E)suberin

Question 21

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 22

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 23

Abscisic acid synthesized in the root travels to different parts of the shoot where it regulates transpirational water loss.What is the most likely way that ABA travels from the root to the various locations within the shoot?

A)vessels and tracheids
B)sieve tubes
C)between cell walls
D)from cell to cell through the plasmodesmata

Question 24

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 25

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 26

A scientist is investigating a hormone response in rose bush stems by removing the apical meristems of the main stems.What is the most likely result of this experiment and what hormone is responsible?

A)New apical buds will develop under the influence of auxin.
B)Larger,deeper roots will form under the influence of cytokinin.
C)More leaf buds will appear along the main stems under the influence of auxin.
D)Flowers will turn yellow and fall off under the influence of auxin.
E)Lateral buds will develop under the influence of cytokinin.

Question 27

Red light and phytochrome are involved in which of the following plant growth responses? Check all that apply.

A)thigmotropic responses
B)inhibition of seed germination
C)elongation of etiolated shoots
D)detection of crowding by neighboring plants

Question 28

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 29

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 30

The directional growth response of plants to touch is called

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

Question 31

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 32

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 discourage early ripening of the fruit

Question 33

A viticulturist wants to grow larger grapes.Which specific hormone would a viticulturist apply to the plants?

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

Question 34

Which of the following are true statements about gibberellins? Check all that apply.

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

Question 35

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 36

In Arabidopsis plants,about 7% of its genome is devoted to processes tied to which molecule?

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

Question 37

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 38

While flipping through an agriculture products catalog,you come across the following advertisement,"The Centralized Ripening System-makes large scale hormone distribution even easier!".What hormone does this product distribute?

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

Question 39

Directional,light-triggered plant development is known as

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

Question 40

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 41

Which part of a root tip is responsible for perceiving gravity?

A)root cap
B)zone of cell division
C)zone of elongation
D)zone of maturation

Question 42

Which of the following describe a role that ethylene plays in plant physiology.Check all that apply.

A)Retarding stem and root elongation
B)Inhibition of leaf abscission
C)Hastening the ripening of fruit
D)Inhibition of lateral bud growth
E)Accelerates the loss of damaged fruits

Question 43

Plants maintain higher levels of phytochrome at their growing tips where phytochrome plays important roles in growth responses to light.Phytochrome levels are also high in areas of the plant that are "greening".What does this suggest about the role of phytochrome in these "greening" zones?

A)Phytochrome is absorbing green wavelengths of light.
B)In these areas,phytochrome is the first step in the electron transport chain of photosynthesis.
C)Phytochrome is facilitating the transcription and translation of photosynthesis related proteins.
D)Phytochrome is facilitating the migration of chlorophyll pigments from other areas of the plant.

Question 44

Why do plants growing outside often have shorter and thicker stems than plants of the same species grown indoors?

A)The plants inside have a more constant source of light and therefore a higher level of phytochrome.
B)The outdoor plants are subject to mechanical stresses and they are exhibiting a thigmomorphogenic response.
C)The outdoor plants are subject to touch by animals and other plants and are exhibiting a thigmotropic response.
D)The indoor plants have elevated levels of auxin and are therefore taller than the outside plants.

Question 45

While researching the effects of light on chlorophyll synthesis in sorghum,you find that brief pulses of red light stimulates the synthesis of chlorophyll a and b.This would suggest that chlorophyll synthesis is directed by the P_r form of phytochrome.

Question 46

How do heat shock proteins protect plants from high temperatures?

A)Heat shock proteins stabilize other proteins so that they don't denature at higher temperatures.
B)Heat shock proteins prevent carbohydrates from being hydrolized at higher temperatures.
C)Heat shock proteins prevent the double helix of DNA molecules from unwinding at higher temperatures.
D)Heat shock proteins prevent lipids from dissolving at higher temperatures.

Question 47

The removal of the root cap eliminates the ability of a root to respond to gravity.

Question 48

Which of the following about seed dormancy is not true?

A)Seed dormancy is common in tropical climates.
B)High levels of abscisic acid trigger seed dormancy.
C)Annual plants frequently utilize seed dormancy to wait until after the dry season has ended before germinating.
D)Embryos inside of some seeds can germinate after hundreds of years.

Question 49

Which of the following statements about abscisic acid are true? Check all that apply.

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 50

Research has shown that cytokinin levels fluctuate seasonally in temperate plants.What season would you expect to see the lowest levels of cytokinins and why would this be adaptive?

A)Spring,because lower levels of cytokinin allow auxin to promote rapid growth in stem height.This will allow the plant to compete effectively for sunlight.
B)Summer,because lower levels of cytokinin would slow growth down and delay leaf aging.This will allow the plant to maximize the production of starch and increase it's sugar reserves.This will help ensure the plant's survival through Autumn and Winter.
C)Autumn,because lower levels of cytokinin at this time of year will induce the production of ethylene.This will result in maturation of fruit and ensure effective seed dispersal before Winter.
D)Winter,because lower levels of cytokinin will place buds into a dormant state.This will protect the underlying tissues from freezing until Spring.