Question 1

The weed killer 2,4-D is a synthetic cytokinin.

Accepted Answer

A) True 
 B)False

Question 2

Gibberellins promote fruit development in some species in which auxin does not.

Accepted Answer

A) True 
 B)False

Question 3

Which of the following statements about 2,4-D is FALSE?

Accepted Answer

A)   It is a synthetic auxin.
B)   It is used as an herbicide.
C)   It is not broken down in plants as readily as IAA.
D)   It is absorbed more readily than IAA
E)   It kills grasses more readily than broad-leaf weeds. .

Question 4

Cell wall extensibility, and thus cell expansion, is increased by ______ but decreased by ______.

Accepted Answer

A)   auxin and ethylene; GA and ABA
B)   auxin and GA; ABA and ethylene
C)   auxin and ABA; GA and ethylene
D)   ABA and ethylene; auxin and GA
E)   ABA and GA; auxin and ethylene

Question 5

Which of the following is a phenolic compound with a structure similar to aspirin?

Accepted Answer

A)   systemin
B)   florigen
C)   brassinosteroids
D)   salicylic acids
E)   jasmonic acid

Question 6

In apical dominance, the apical bud:

Accepted Answer

A)   inhibits the growth of lateral buds.
B)   stimulates the growth of lateral buds.
C)   stimulates the upward growth of the stem.
D)   stimulates the growth of leaves.
E)   inhibits the downward growth of the root.

Question 7

In climacteric fruits, there is a large increase in cellular respiration during ripening.

Accepted Answer

A) True 
 B)False

Question 8

______ activates the biosynthesis of ________, which then activates the genes that encode protease inhibitors.

Accepted Answer

A)   Systemin; jasmonic acid
B)   Jasmonic acid; auxin
C)   Brassinosteroid; systemin
D)   Salicylic acid; jasmonic acid
E)   Systemin brassinosteroids

Question 9

Which of the following statements concerning endogenous brassinosteroids is FALSE?

Accepted Answer

A)   They are found in virtually every part of the plant.
B)   They are synthesized from castasterone.
C)   They are essential for tracheary element differentiation.
D)   They are required for normal plant growth.
E)   They are transported from root to shoot in the xylem.

Question 10

An excised leaf floated in a kinetin solution will remain green longer than a leaf floated in water.

Accepted Answer

A) True 
 B)False

Question 11

Salicylic acid regulates thermogenesis in members of the arum family.

Accepted Answer

A) True 
 B)False

Question 12

In Arabidopsis, the ethylene receptor is located in the plasma membrane.

Accepted Answer

A) True 
 B)False

Question 13

Rice plants grow rapidly and become spindly due to the presence of gibberellic acid produced by a fungus.

Accepted Answer

A) True 
 B)False

Question 14

In roots of Arabidopsis, cytokinin ______ the initiation of lateral roots by preventing the establishment of a(n)  ______ gradient.

Accepted Answer

A)   inhibits; auxin
B)   inhibits; gibberellin
C)   stimulates; auxin
D)   stimulates; gibberellin
E)   stimulates; ethylene

Question 15

Based on the results of experiments with cultured mesophyll cells of Zinnia elegans, you would predict that if brassinosteroids were excluded from the culture medium, no tracheary elements would be formed.

Accepted Answer

A) True 
 B)False

Question 16

Plant hormones usually act alone and only occasionally "cross-talk."

Accepted Answer

A) True 
 B)False

Question 17

In studies of leaf senescence, when an excised leaf containing radioactive amino acids is spotted with a kinetin-containing solution, the spot:

Accepted Answer

A)   turns yellow and becomes nonradioactive.
B)   turns yellow and becomes more radioactive.
C)   remains green and becomes nonradioactive.
D)   remains green and becomes more radioactive.
E)   turns brown and becomes nonradioactive.

Question 18

In the acid-growth hypothesis of cell wall extensibility, which of the following events occurs FIRST?

Accepted Answer

A)   Expansins disrupt hydrogen bonds.
B)   Protons are pumped into the cell wall.
C)   Specific genes are activated.
D)   A proton-pumping enzyme is activated.
E)   Cross-links between noncellulosic polysaccharides are broken.

Question 19

Polar transport is ______ in stems, _______in leaves, and ______ in roots.

Accepted Answer

A)   acropetal; acropetal; acropetal
B)   basipetal; basipetal; basipetal
C)   acropetal; acropetal; basipetal
D)   basipetal; acropetal; acropetal
E)   basipetal; basipetal; acropetal

Question 20

The transport of auxin can be nonpolar as well as polar.

Accepted Answer

A) True 
 B)False

Exam 27: Regulating Growth and Development: the Plant Hormones

In the acid-growth hypothesis of cell wall extensibility, which of the following events occurs FIRST?

Correct AnswerverifiedShow Answer

______ activates the biosynthesis of ________, which then activates the genes that encode protease inhibitors.

Correct AnswerverifiedShow Answer

In climacteric fruits, there is a large increase in cellular respiration during ripening.

Correct AnswerverifiedShow Answer

In apical dominance, the apical bud:

Correct AnswerverifiedShow Answer

Rice plants grow rapidly and become spindly due to the presence of gibberellic acid produced by a fungus.

Correct AnswerverifiedShow Answer

An excised leaf floated in a kinetin solution will remain green longer than a leaf floated in water.

Correct AnswerverifiedShow Answer

Cell wall extensibility, and thus cell expansion, is increased by ______ but decreased by ______.

Correct AnswerverifiedShow Answer

Gibberellins promote fruit development in some species in which auxin does not.

Correct AnswerverifiedShow Answer

Which of the following statements about 2,4-D is FALSE?

Correct AnswerverifiedShow Answer

In roots of Arabidopsis, cytokinin ______ the initiation of lateral roots by preventing the establishment of a(n) ______ gradient.

Correct AnswerverifiedShow Answer

Which of the following statements concerning endogenous brassinosteroids is FALSE?

Correct AnswerverifiedShow Answer

Salicylic acid regulates thermogenesis in members of the arum family.

Correct AnswerverifiedShow Answer

In Arabidopsis, the ethylene receptor is located in the plasma membrane.

Correct AnswerverifiedShow Answer

Plant hormones usually act alone and only occasionally "cross-talk."

Correct AnswerverifiedShow Answer

Polar transport is ______ in stems, _______in leaves, and ______ in roots.

Correct AnswerverifiedShow Answer

Based on the results of experiments with cultured mesophyll cells of Zinnia elegans, you would predict that if brassinosteroids were excluded from the culture medium, no tracheary elements would be formed.

Correct AnswerverifiedShow Answer

In studies of leaf senescence, when an excised leaf containing radioactive amino acids is spotted with a kinetin-containing solution, the spot:

Correct AnswerverifiedShow Answer

Which of the following is a phenolic compound with a structure similar to aspirin?

Correct AnswerverifiedShow Answer

The transport of auxin can be nonpolar as well as polar.

Correct AnswerverifiedShow Answer

The weed killer 2,4-D is a synthetic cytokinin.

Correct AnswerverifiedShow Answer

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activates the biosynthesis of __, which then activates the genes that encode protease inhibitors.

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Cell wall extensibility, and thus cell expansion, is increased by but decreased by .

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In roots of Arabidopsis, cytokinin the initiation of lateral roots by preventing the establishment of a(n) gradient.

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Polar transport is __ in stems, _in leaves, and ____ in roots.

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