Question 1

What is the unique physical property of ethylene, among all of the major plant hormones?

Accepted Answer

A)  Low melting point 
B)  It exists as a gas 
C)  High boiling point 
D)  Insolubility in ether 
E)  Water solubility 
A)  Low melting point 
B)  It exists as a gas 
C)  High boiling point 
D)  Insolubility in ether 
E)  Water solubility

Question 2

Phototropins are

Accepted Answer

A)  hormones. 
B)  hormone receptors. 
C)  light receptors for photomorphogenesis. 
D)  light receptors for phototropism. 
E)  closely related to phytochromes. 
A)  hormones. 
B)  hormone receptors. 
C)  light receptors for photomorphogenesis. 
D)  light receptors for phototropism. 
E)  closely related to phytochromes.

Question 3

Refer to the figure below.Each pair includes a dwarf plant with a hormonal deficiency and a normal-sized plant of the same species.   By comparing the plants within the same species and then making comparisons between species, you would find that plant hormones

Accepted Answer

A)  always have the same effects. 
B)  can have the same general effects in different species. 
C)  operate in dwarf plants. 
D)  are not present in dwarf plants. 
E)  have different effects in different plants. 
A)  always have the same effects. 
B)  can have the same general effects in different species. 
C)  operate in dwarf plants. 
D)  are not present in dwarf plants. 
E)  have different effects in different plants.

Question 4

Which of the following steps is initially most crucial for the survival of the growing seedling that germinated an inch underground?

Accepted Answer

A)  Production of chlorophyll 
B)  Rapid elongation of the shoot 
C)  Breaking of dormancy 
D)  Rapid start of photosynthesis 
E)  Expansion of cotyledons 
A)  Production of chlorophyll 
B)  Rapid elongation of the shoot 
C)  Breaking of dormancy 
D)  Rapid start of photosynthesis 
E)  Expansion of cotyledons

Question 5

A botanist is trying to isolate all of the auxin produced in a bean plant by extracting it from seedlings in a range of developmental stages.Which of the following features of plant hormones must the scientist take into consideration while planning the extraction protocol?

Accepted Answer

A)  They have a single specific role. 
B)  They affect mainly the cells that produce them. 
C)  They are species-specific. 
D)  They are produced in many different parts of the plant. 
E)  They elicit rapid responses. 
A)  They have a single specific role. 
B)  They affect mainly the cells that produce them. 
C)  They are species-specific. 
D)  They are produced in many different parts of the plant. 
E)  They elicit rapid responses.

Question 6

The Darwins' experiments on phototropism in seedlings of a grass plant

Accepted Answer

A)  established that the base of the coleoptile contained the photoreceptor for phototropism. 
B)  led to the hypothesis that there exists a growth-promoting substance in the coleoptile. 
C)  showed that the growing region of the coleoptile and the light-sensing area were the same. 
D)  showed that the tip of the coleoptile was not required for the phototrophic response. 
E)  showed that light has no effect on plant development. 
A)  established that the base of the coleoptile contained the photoreceptor for phototropism. 
B)  led to the hypothesis that there exists a growth-promoting substance in the coleoptile. 
C)  showed that the growing region of the coleoptile and the light-sensing area were the same. 
D)  showed that the tip of the coleoptile was not required for the phototrophic response. 
E)  showed that light has no effect on plant development.

Question 7

Refer to the figure below.   Both sets of tomatoes were picked before ripening.The tomatoes on the right are red, while those on the left are still green, because

Accepted Answer

A)  the red tomatoes have been treated with cytokinins. 
B)  the red tomatoes have been treated with gibberellins. 
C)  the red tomatoes have been treated with auxin. 
D)  the red tomatoes have been treated with ethylene. 
E)  the green tomatoes have been exposed to far-red light. 
A)  the red tomatoes have been treated with cytokinins. 
B)  the red tomatoes have been treated with gibberellins. 
C)  the red tomatoes have been treated with auxin. 
D)  the red tomatoes have been treated with ethylene. 
E)  the green tomatoes have been exposed to far-red light.

Question 8

Florists use silver thiosulfate to

Accepted Answer

A)  delay abscission of petals caused by the action of auxin. 
B)  delay abscission of leaves caused by the action of abscisic acid. 
C)  keep petals from turning brown because of the action of ethylene. 
D)  keep leaves green longer by promoting the action of cytokinins. 
E)  prevent microbial decay of senescing leaves and petals. 
A)  delay abscission of petals caused by the action of auxin. 
B)  delay abscission of leaves caused by the action of abscisic acid. 
C)  keep petals from turning brown because of the action of ethylene. 
D)  keep leaves green longer by promoting the action of cytokinins. 
E)  prevent microbial decay of senescing leaves and petals.

Question 9

Refer to the figure below, showing two plants of the same type grown under different experimental conditions.   Which scenario describing the use of mutant plants in hormone studies such as this one is realistic?

Accepted Answer

A)  The plants are both normal, but only one has been subjected to a genetic screen. 
B)  The plants are both dwarf mutants, but only one has been subjected to a genetic screen. 
C)  The plants are both dwarf mutants, but one has grown to normal proportions after being treated with an external application of a growth hormone such as gibberellin. 
D)  The plants are both normal, but one reversed its growth and became a dwarf after being treated with a growth hormone inhibitor. 
E)  The plants were subjected to different regimes of red and far-red light. 
A)  The plants are both normal, but only one has been subjected to a genetic screen. 
B)  The plants are both dwarf mutants, but only one has been subjected to a genetic screen. 
C)  The plants are both dwarf mutants, but one has grown to normal proportions after being treated with an external application of a growth hormone such as gibberellin. 
D)  The plants are both normal, but one reversed its growth and became a dwarf after being treated with a growth hormone inhibitor. 
E)  The plants were subjected to different regimes of red and far-red light.

Question 10

Which plant hormone induces fruit softening?

Accepted Answer

A)  Cytokinin 
B)  Ethylene 
C)  Gibberellin 
D)  Auxin 
E)  Brassinosteroid 
A)  Cytokinin 
B)  Ethylene 
C)  Gibberellin 
D)  Auxin 
E)  Brassinosteroid

Question 11

If you see a leaf on a tomato plant drop after a long period of vigorous photosynthesis and this is followed by physiological decline, you can conclude that auxin stopped antagonizing

Accepted Answer

A)  ethylene. 
B)  brassinosteroid. 
C)  phototropin. 
D)  cytokinin. 
E)  gibberellin. 
A)  ethylene. 
B)  brassinosteroid. 
C)  phototropin. 
D)  cytokinin. 
E)  gibberellin.

Question 12

The plant hormones called auxins do not affect

Accepted Answer

A)  root initiation 
B)  leaf abscission 
C)  apical dominance 
D)  cell expansion 
E)  inhibition of stem elongation 
A)  root initiation 
B)  leaf abscission 
C)  apical dominance 
D)  cell expansion 
E)  inhibition of stem elongation

Question 13

Phytochrome does not

Accepted Answer

A)  absorb red light to become activated. 
B)  absorb far-red light to become deactivated. 
C)  act as a protein kinase. 
D)  bind to transcription factors. 
E)  promote formation of the apical hook during germination. 
A)  absorb red light to become activated. 
B)  absorb far-red light to become deactivated. 
C)  act as a protein kinase. 
D)  bind to transcription factors. 
E)  promote formation of the apical hook during germination.

Question 14

All of the following may serve to break dormancy and initiate seed germination except

Accepted Answer

A)  abrasion. 
B)  fire. 
C)  exposure to water. 
D)  treatment with abscisic acid. 
E)  treatment with gibberellins. 
A)  abrasion. 
B)  fire. 
C)  exposure to water. 
D)  treatment with abscisic acid. 
E)  treatment with gibberellins.

Question 15

The cellular mechanism by which auxin promotes cell growth is called the

Accepted Answer

A)  cohesion-tension theory. 
B)  acid growth hypothesis. 
C)  Turing paradox. 
D)  phototropic hypothesis. 
E)  expansion hypothesis. 
A)  cohesion-tension theory. 
B)  acid growth hypothesis. 
C)  Turing paradox. 
D)  phototropic hypothesis. 
E)  expansion hypothesis.

Question 16

Explain the molecular chain of events that occurs in a plant when its phytochrome is exposed to red light.

Accepted Answer

When the "default" phytochrome P_r absorbs

Question 17

Most plant hormones are

Accepted Answer

A)  steroids. 
B)  peptides. 
C)  neurotransmitters. 
D)  small organic molecules. 
E)  based on tyrosine. 
A)  steroids. 
B)  peptides. 
C)  neurotransmitters. 
D)  small organic molecules. 
E)  based on tyrosine.

Question 18

What treatment can hasten the ripening of figs due to its induction of ethylene production?

Accepted Answer

A)  Removal of leaf cover 
B)  Application of auxin 
C)  Washing with soap 
D)  Coating with oil 
E)  Wounding the fruit 
A)  Removal of leaf cover 
B)  Application of auxin 
C)  Washing with soap 
D)  Coating with oil 
E)  Wounding the fruit

Question 19

If a shoot cutting is treated with auxin, which of the following is likely to result?

Accepted Answer

A)  Extensive root production 
B)  Suppression of apical dominance 
C)  Growth of lateral buds 
D)  Bolting of the shoot 
E)  Flowering 
A)  Extensive root production 
B)  Suppression of apical dominance 
C)  Growth of lateral buds 
D)  Bolting of the shoot 
E)  Flowering

Question 20

Refer to the figure below.   The leaf on the right is green and healthy because

Accepted Answer

A)  it has been exposed to far-red light. 
B)  it has been exposed to blue or UV light. 
C)  it has been treated with ethylene. 
D)  it has been treated with cytokinins. 
E)  it is a mutant that lacks a functional brassinosteroid signal transduction pathway. 
A)  it has been exposed to far-red light. 
B)  it has been exposed to blue or UV light. 
C)  it has been treated with ethylene. 
D)  it has been treated with cytokinins. 
E)  it is a mutant that lacks a functional brassinosteroid signal transduction pathway.

Exam 36: Regulation of Plant Growth

What is the unique physical property of ethylene, among all of the major plant hormones?

Phototropins are

Refer to the figure below.Each pair includes a dwarf plant with a hormonal deficiency and a normal-sized plant of the same species. By comparing the plants within the same species and then making comparisons between species, you would find that plant hormones

Which of the following steps is initially most crucial for the survival of the growing seedling that germinated an inch underground?

A botanist is trying to isolate all of the auxin produced in a bean plant by extracting it from seedlings in a range of developmental stages.Which of the following features of plant hormones must the scientist take into consideration while planning the extraction protocol?

The Darwins' experiments on phototropism in seedlings of a grass plant

Refer to the figure below. Both sets of tomatoes were picked before ripening.The tomatoes on the right are red, while those on the left are still green, because

Florists use silver thiosulfate to

Refer to the figure below, showing two plants of the same type grown under different experimental conditions. Which scenario describing the use of mutant plants in hormone studies such as this one is realistic?

Which plant hormone induces fruit softening?

If you see a leaf on a tomato plant drop after a long period of vigorous photosynthesis and this is followed by physiological decline, you can conclude that auxin stopped antagonizing

The plant hormones called auxins do not affect

Phytochrome does not

All of the following may serve to break dormancy and initiate seed germination except

The cellular mechanism by which auxin promotes cell growth is called the

Explain the molecular chain of events that occurs in a plant when its phytochrome is exposed to red light.

Most plant hormones are

What treatment can hasten the ripening of figs due to its induction of ethylene production?

If a shoot cutting is treated with auxin, which of the following is likely to result?

Refer to the figure below. The leaf on the right is green and healthy because

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