Deck 40: Sensory Systems in Plants

Question 1

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.

Answer 1

C

Question 2

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.

Answer 2

C

Question 3

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

Answer 3

A

Question 4

_______________ 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

Question 5

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

Question 6

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

Question 7

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.

Question 8

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

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

Question 9

While flipping through an agriculture products catalog, you come across the following advertisment, "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

Question 10

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

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

Question 11

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

Question 12

The elongation of stems is stimulated by

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

Question 13

Which cell structure is most likely responsible for sensing gravity?

A)central vacuole
B)Golgi appartus
C)chloroplast
D)amyloplast

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.

Question 15

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

Question 16

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.

Question 17

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

Question 18

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

Question 19

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.

Question 20

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 $\alpha$ -amylase.Which food source are gibberellins targeting with the release of $\alpha$ -amylase?

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

Question 21

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.

Question 22

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.

Question 23

Directional, light-triggered plant development is known as

A)thigmotropism.
B)phototropism.
C)thigmonasty.
D)photomorphogenesis.

Question 24

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.

Question 25

Red light and phytochrome are involved in which of the following plant growth responses? Check all that apply._____ thigmotropic responses
__X__ inhibition of seed germination
__X__ elongation of etiolated shoots
__X__ detection of crowding by neighboring plants

Question 26

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

Question 27

Which of the following describe a role that ethylene plays in plant physiology.Check all that apply.__X__ Retarding stem and root elongation.__X__ Hastening the ripening of fruit._____ Inhibition of leaf abscission.__X__ Inhibition of lateral bud growth.__X__ Accelerates the loss of damaged fruits.

Question 28

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 29

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.

Question 30

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

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

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.

Question 33

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 34

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.

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

Question 36

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.

Question 37

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.

Question 38

The directional growth response of plants to touch is called

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

Question 39

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

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

Question 40

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.

Question 41

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.

Question 42

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

Question 43

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

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.