Question 1

Explain the mechanisms required for a Venus flytrap to close its trap when stimulated by an insect.

Accepted Answer

Turgor pressure is required to cause the Venus flytrap to close.Turgor pressure is created when the trigger cells are stimulated.An electrical charge is transmitted throughout the lobes of the leaf.One explanation for the cause of this electrical charge is that the lobes of the leaf secrete hydrogen ions into the cell walls allowing them to swell by osmosis.Another explanation is that the lobes on the inner portion of the midrib lose ions leading to a water loss through osmosis and collapsing the cells.

Question 2

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.
-If a plant is placed on its side,cells on the lower side of the stem will respond to gravity and elongate,making the stem turn so that it continues to grow downward.

Accepted Answer

A) True 
 B)False  False

Question 3

Which of the following plant hormones was discovered in infected rice seedlings that grew extremely tall and slender with "foolish seedling disease"?

Accepted Answer

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

Question 4

________ 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) Gibberellins 
A) Ethylene 
B) Cytokinins 
C) Abscisic acid 
D) Gibberellins

Question 5

Explain how a hormone will trigger the signal transduction pathway in a plant.

Accepted Answer

1.Receptor: a molecule in the plasma mem

Question 6

Which of the following statements best describes how plants use hormones during signal transduction?

Accepted Answer

A) The hormone will bind to a specific receptor in the plasma membrane.It will then trigger a series of relay proteins that alter the signal into one that will impact the cellular machinery.Once the machinery is altered a change in gene expression will occur causing a change in the physical expression of the plant. 
B) The hormone will trigger a series of relay proteins to alter the signal into one that will impact the cellular machinery.Once the signal is changed the hormone will bind to a specific receptor in the plasma membrane.It will then cause a change in gene expression to occur causing a change in the physical expression of the plant. 
C) The hormone will bind to a specific receptor in the plasma membrane.It will then trigger a series of relay proteins that alter the signal into one that will impact the cellular machinery.Once the machinery is altered a change in the physical expression will occur causing a change in the actual genes of the plant. 
D) None of these describes how plants use hormones during signal transduction. 
A) The hormone will bind to a specific receptor in the plasma membrane.It will then trigger a series of relay proteins that alter the signal into one that will impact the cellular machinery.Once the machinery is altered a change in gene expression will occur causing a change in the physical expression of the plant. 
B) The hormone will trigger a series of relay proteins to alter the signal into one that will impact the cellular machinery.Once the signal is changed the hormone will bind to a specific receptor in the plasma membrane.It will then cause a change in gene expression to occur causing a change in the physical expression of the plant. 
C) The hormone will bind to a specific receptor in the plasma membrane.It will then trigger a series of relay proteins that alter the signal into one that will impact the cellular machinery.Once the machinery is altered a change in the physical expression will occur causing a change in the actual genes of the plant. 
D) None of these describes how plants use hormones during signal transduction.

Question 7

Which of the following plant hormones breaks dormancy in seeds and buds when applied to the plant?

Accepted Answer

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

Question 8

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

Question 9

Which of the following plant hormones prevents plant tissues from senescing,or aging?

Accepted Answer

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

Question 10

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.
-A hormone is produced in small amounts in a tissue,and it causes a physiological action within that same tissue soon after its production.

Accepted Answer

A) True 
 B)False

Question 11

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

Accepted Answer

A) phytochrome 
B) phototropin 
C) gibberellins 
D) cytokinins 
E) Phytochrome and phototropin are correct. 
A) phytochrome 
B) phototropin 
C) gibberellins 
D) cytokinins 
E) Phytochrome and phototropin are correct.

Question 12

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. 
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.

Question 13

Removing the top of a plant to create fuller growth involves which of the following hormones?

Accepted Answer

A) auxins 
B) ethylene 
C) gibberellins 
D) cytokinins 
A) auxins 
B) ethylene 
C) gibberellins 
D) cytokinins

Question 14

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

Question 15

A plant's response to an external stimulus involves receptors.A receptor that responds to light normally contains

Accepted Answer

A) a series of relay proteins. 
B) a pigment component. 
C) a transduction pathway. 
D) an end product of a metabolic pathway. 
A) a series of relay proteins. 
B) a pigment component. 
C) a transduction pathway. 
D) an end product of a metabolic pathway.

Question 16

How does gibberellin actually work?

Accepted Answer

A) In the presence of blue light,it triggers additional photosynthesis and growth. 
B) It attaches to a plasma membrane receptor and results in gene activation to produce the enzyme amylase that releases sugars for additional cell growth,division,and elongation. 
C) In the presence of light,it increases the formation of additional DNA that codes for additional plant structures. 
D) In the presence of unidirectional light,it moves to the shady side and activates an ATP-driven proton pump that results in weakened cell walls and eventual elongation. 
E) In the presence of light,it increases the turgor pressure of the cell and accelerates growth. 
A) In the presence of blue light,it triggers additional photosynthesis and growth. 
B) It attaches to a plasma membrane receptor and results in gene activation to produce the enzyme amylase that releases sugars for additional cell growth,division,and elongation. 
C) In the presence of light,it increases the formation of additional DNA that codes for additional plant structures. 
D) In the presence of unidirectional light,it moves to the shady side and activates an ATP-driven proton pump that results in weakened cell walls and eventual elongation. 
E) In the presence of light,it increases the turgor pressure of the cell and accelerates growth.

Question 17

Which of the following is NOT a physiological change related to photoperiodism?

Accepted Answer

A) seed germination 
B) root branching 
C) breaking bud dormancy 
D) some flowering 
E) onset of senescence 
A) seed germination 
B) root branching 
C) breaking bud dormancy 
D) some flowering 
E) onset of senescence

Question 18

Which statement is NOT true about photoperiodism?

Accepted Answer

A) A short-day plant flowers when the day length is shorter than a critical length. 
B) A day-neutral plant flowers according to some form of regulation other than photoperiodism. 
C) A long-day plant will flower when the day length is longer than a critical length. 
D) The phytochrome form Pfr is converted to Pr in daylight,producing the active form that induces flowering in long-day plants. 
A) A short-day plant flowers when the day length is shorter than a critical length. 
B) A day-neutral plant flowers according to some form of regulation other than photoperiodism. 
C) A long-day plant will flower when the day length is longer than a critical length. 
D) The phytochrome form Pfr is converted to Pr in daylight,producing the active form that induces flowering in long-day plants.

Question 19

Which of the following pertain to movement of plants?

Accepted Answer

A) nastic movements 
B) thigmotropism 
C) phototropism 
D) gravitropism 
E) All of the choices are correct. 
A) nastic movements 
B) thigmotropism 
C) phototropism 
D) gravitropism 
E) All of the choices are correct.

Question 20

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

Exam 26: Flowering Plants: Control of Growth Responses

Explain the mechanisms required for a Venus flytrap to close its trap when stimulated by an insect.

Which of the following plant hormones was discovered in infected rice seedlings that grew extremely tall and slender with "foolish seedling disease"?

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

Explain how a hormone will trigger the signal transduction pathway in a plant.

Which of the following statements best describes how plants use hormones during signal transduction?

Which of the following plant hormones breaks dormancy in seeds and buds when applied to the plant?

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

Which of the following plant hormones prevents plant tissues from senescing,or aging?

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

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?

Removing the top of a plant to create fuller growth involves which of the following hormones?

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

A plant's response to an external stimulus involves receptors.A receptor that responds to light normally contains

How does gibberellin actually work?

Which of the following is NOT a physiological change related to photoperiodism?

Which statement is NOT true about photoperiodism?

Which of the following pertain to movement of plants?

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

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