Question 1

Which of the following statements is NOT correct about a circadian rhythm?

Accepted Answer

A)  These rhythms tend to persist even in the absence of daily light cues.
B)  An example is the opening of stomates in the morning and their closing at night.
C)  If plants are maintained in total darkness or total light,their circadian rhythm acts on a faster time scale.
D)  The primary usefulness of circadian rhythms seems to be to measure day-length changes so plants respond appropriately to seasonal environmental changes.E) None of the above
F) C) and D)

Question 2

Which of the following defense systems would most likely have evolved in response to the leaves of a plant being preyed upon by aphids?

Accepted Answer

A)  After the plant is chewed it produces a proteinase inhibitor that will destroy the digestive enzymes of the predator feeding upon it.The proteinase inhibitor will be produced throughout the entire plant in order to discourage predation in other areas of the plant.
B)  After the plant is chewed it produces a proteinase inhibitor that will destroy the digestive enzymes of the predator feeding upon it.The proteinase inhibitor is produced at the site of injury in an attempt to stem the loss of phloem from the site of injury.
C)  The leaves of various plants have evolved to resemble the eggs butterflies in an attempt to decrease the number of butterflies that lay eggs on them.
D)  The plants produce tannins in the outer leaves in an attempt to discourage predation by insects.
E)  All of the choices are correct.F) C) and D)
G) A) and B)

Question 3

Photoperiodism requires

Accepted Answer

A)  a biological clock which can measure time.
B)  a photoreceptor called phytochrome.
C)  increased turgor pressure.
D)  protease inhibitors.
E)  a biological clock which can measure time and a photoreceptor called phytochrome only are correct.F) D) and E)
G) None of the above

Question 4

Figure:  The cylinders in this experiment represent a 24-hour period.The light area represents light periods during a 24-hr.period and the dark area represents dark periods during a 24-hr.period.The critical length of dark vs.light periods for flowering is depicted by the dotted line.Note that some plants are flowering and some are not flowering.Study the results of this experiment on photoperiodism and flowering to determine whether the following statements are True or False.
-Short-day plants flower when the day length is longer than the critical length.

Accepted Answer

A) True 
 B)False

Question 5

Plant hormones are generally produced in _______ tissues.

Accepted Answer

A)  cortical (cortex) 
B)  epidermal
C)  meristematic
D)  vascular
E)  floralF) A) and C)
G) A) and B)

Question 6

Which of the following is (are) an effect(s) of auxin?

Accepted Answer

A)  Applied to a woody cutting,auxin causes roots to develop.
B)  Auxin production by seeds promotes the growth of fruit.
C)  Trees sprayed with auxin will keep mature fruit from falling to the ground.
D)  Under the effect of gravity,auxin moves to the lower surface of roots and stems,causing roots to curve downward and stems to curve upward.
E)  All of the choices are effects of auxin.F) D) and E)
G) B) and D)

Question 7

The conclusion drawn from these results is that the length of the dark period,not the light period,controls flowering.

Accepted Answer

A) True 
 B)False

Question 8

Which of the following plant hormones stimulates the ripening of fruit and inhibits plant growth?

Accepted Answer

A)  abscisic acid
B)  auxin
C)  cytokinin
D)  ethylene
E)  gibberellinF) A) and D)
G) A) and E)

Question 9

The germinating corn seed pictured below is displaying

Accepted Answer

A)  negative gravitropism.
B)  positive gravitropism.
C)  thigmotropism.
D)  negative phototropism.
E)  positive phototropism.F) C) and D)
G) All of the above

Question 10

Auxin stimulates leaf release,while ethylene keeps leaves from falling.

Accepted Answer

A) True 
 B)False

Question 11

Cyanogenic glycosides are secondary metabolites that are used as medicines for people.

Accepted Answer

A) True 
 B)False

Question 12

Which of the following plant hormones was studied in the 1880s by Charles and Francis Darwin in experiments on phototropism?

Accepted Answer

A)  abscisic acid
B)  auxin
C)  cytokinin
D)  ethylene
E)  gibberellinF) A) and B)
G) B) and E)

Question 13

Which of the following plant hormones is associated with the closure of stomata in a plant under water stress?

Accepted Answer

A)  abscisic acid
B)  auxin
C)  cytokinin
D)  ethylene
E)  gibberellinF) A) and E)
G) C) and D)

Question 14

Which statement about plant hormones is NOT true?

Accepted Answer

A)  Plant hormones include at least one form that is a gas.
B)  Each naturally occurring hormone has a specific chemical structure.
C)  Hormones are among the principal internal regulators of plant growth.
D)  Responses to plant hormones may be observed in nearly any part of a plant.
E)  All known growth regulators of plants are chemicals produced naturally in plants.F) A) and E)
G) C) and E)

Question 15

The general sequence by which a plant responds to external stimuli is

Accepted Answer

A)  chloroplast-vascular bundle-sap.
B)  reception-transduction-cellular response.
C)  sensory nerve-interneuron-motor nerve.
D)  input-reflex-output.
E)  leaf-stem-root.F) A) and D)
G) None of the above

Question 16

Plants could readily develop seasonal responses for flowering based on temperature changes but have "elected" through evolution to manage their rhythms based on a comparison of daylight and darkness.Why has the day-night ratio system been selected?

Accepted Answer

A)  Temperature has no effect upon plant biochemistry.
B)  Temperature is a gradation but day/night is all-or-nothing.
C)  A plant's nervous system is tuned to light stimuli and not to temperature stimuli.
D)  Temperatures fluctuate widely across seasons and from year to year,but photoperiod comparisons are a more reliable indicator of season.E) B) and D)
F) All of the above

Question 17

Figure:  The cylinders in this experiment represent a 24-hour period.The light area represents light periods during a 24-hr.period and the dark area represents dark periods during a 24-hr.period.The critical length of dark vs.light periods for flowering is depicted by the dotted line.Note that some plants are flowering and some are not flowering.Study the results of this experiment on photoperiodism and flowering to determine whether the following statements are True or False.
-Short-day plants flower when the day length is shorter than the critical length,but the required dark period is interrupted by a flash of light.

Accepted Answer

A) True 
 B)False

Question 18

Which of the following is a receptor that responds to light?

Accepted Answer

A)  photochrome
B)  phototropin
C)  gibberellins
D)  cytokinins
E)  photochrome and phototropin are correct.F) A) and E)
G) C) and D)

Question 19

______ is often referred to as the "stress" hormone since it initiates and maintains seed and bud dormancy.

Accepted Answer

A)  Ethylene
B)  Cytokinins
C)  Abscisic acid
D)  GibberellinsE) B) and D)
F) A) and C)

Question 20

Which plant hormone produced in apical meristems inhibits the growth of axillary buds?

Accepted Answer

A)  abscisic acid
B)  auxin
C)  cytokinin
D)  ethylene
E)  gibberellinF) B) and E)
G) A) and B)

Exam 26: Flowering Plants: Control of Growth Responses

Which of the following is a receptor that responds to light?

Correct Answer
verified

Auxin stimulates leaf release,while ethylene keeps leaves from falling.

Correct Answer
verified

Photoperiodism requires

Correct Answer
verified

Which of the following is (are) an effect(s) of auxin?

Correct Answer
verified

Which plant hormone produced in apical meristems inhibits the growth of axillary buds?

Correct Answer
verified

Which of the following plant hormones stimulates the ripening of fruit and inhibits plant growth?

Correct Answer
verified

Which statement about plant hormones is NOT true?

Correct Answer
verified

Plants could readily develop seasonal responses for flowering based on temperature changes but have "elected" through evolution to manage their rhythms based on a comparison of daylight and darkness.Why has the day-night ratio system been selected?

Correct Answer
verified

Correct Answer
verified

______ is often referred to as the "stress" hormone since it initiates and maintains seed and bud dormancy.

Correct Answer
verified

Correct Answer
verified

The general sequence by which a plant responds to external stimuli is

Correct Answer
verified

Which of the following plant hormones is associated with the closure of stomata in a plant under water stress?

Correct Answer
verified

Which of the following statements is NOT correct about a circadian rhythm?

Correct Answer
verified

Which of the following plant hormones was studied in the 1880s by Charles and Francis Darwin in experiments on phototropism?

Correct Answer
verified

Which of the following defense systems would most likely have evolved in response to the leaves of a plant being preyed upon by aphids?

Correct Answer
verified

The germinating corn seed pictured below is displaying

Correct Answer
verified

Cyanogenic glycosides are secondary metabolites that are used as medicines for people.

Correct Answer
verified

The conclusion drawn from these results is that the length of the dark period,not the light period,controls flowering.

Correct Answer
verified

Plant hormones are generally produced in _______ tissues.

Correct Answer
verified

Exam 26: Flowering Plants: Control of Growth Responses

Which of the following is a receptor that responds to light?

Correct AnswerverifiedShow Answer

Auxin stimulates leaf release,while ethylene keeps leaves from falling.

Correct AnswerverifiedShow Answer

Photoperiodism requires

Correct AnswerverifiedShow Answer

Which of the following is (are) an effect(s) of auxin?

Correct AnswerverifiedShow Answer

Which plant hormone produced in apical meristems inhibits the growth of axillary buds?

Correct AnswerverifiedShow Answer

Which of the following plant hormones stimulates the ripening of fruit and inhibits plant growth?

Correct AnswerverifiedShow Answer

Which statement about plant hormones is NOT true?

Correct AnswerverifiedShow Answer

Plants could readily develop seasonal responses for flowering based on temperature changes but have "elected" through evolution to manage their rhythms based on a comparison of daylight and darkness.Why has the day-night ratio system been selected?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

______ is often referred to as the "stress" hormone since it initiates and maintains seed and bud dormancy.

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

The general sequence by which a plant responds to external stimuli is

Correct AnswerverifiedShow Answer

Which of the following plant hormones is associated with the closure of stomata in a plant under water stress?

Correct AnswerverifiedShow Answer

Which of the following statements is NOT correct about a circadian rhythm?

Correct AnswerverifiedShow Answer

Which of the following plant hormones was studied in the 1880s by Charles and Francis Darwin in experiments on phototropism?

Correct AnswerverifiedShow Answer

Which of the following defense systems would most likely have evolved in response to the leaves of a plant being preyed upon by aphids?

Correct AnswerverifiedShow Answer

The germinating corn seed pictured below is displaying

Correct AnswerverifiedShow Answer

Cyanogenic glycosides are secondary metabolites that are used as medicines for people.

Correct AnswerverifiedShow Answer

The conclusion drawn from these results is that the length of the dark period,not the light period,controls flowering.

Correct AnswerverifiedShow Answer

Plant hormones are generally produced in _______ tissues.

Correct AnswerverifiedShow Answer

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