Exam 26: Flowering Plants: Control of Growth Responses

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.

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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.

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

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

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1. Receptor: a molecule in the plasma me...

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

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

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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 P_fr is converted to P_r in daylight, producing the active form that induces flowering in long-day plants.

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