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Life, 4/e

Ricki Lewis, University of New York at Albany
Mariëlle Hoefnagels, University of Oklahoma
Douglas Gaffin, University of Oklahoma
Bruce Parker, Utah Valley State College

Plant Responses to Stimuli

Chapter Quiz


1	True or false. Hormones regulate only a limited number of aspects of plant growth, and a single hormone elicits only one type of response.
		A)	True
		B)	False


2	What is the specific action of auxin?
		A)	triggers seed germination by initiating water uptake
		B)	initiates leaf and fruit abscission
		C)	causes membrane proteins to pump protons into the cell wall that, in turn, activate enzymes
		D)	All of these are correct.


3	Which of the following chemicals are herbicides?
		A)	indoleacetic acid
		B)	2, 4 ~ dichlorophenoxyacetic acid
		C)	ethylene
		D)	a and b


4	What action cannot be attributed to gibberellin?
		A)	stimulates shoot elongation
		B)	stimulates seed germination
		C)	hastens fruit ripening
		D)	All of these are correct.


5	What class of hormone is responsible for cell division in young leaves?
		A)	auxins
		B)	gibberellins
		C)	cytokinins
		D)	ethylene


6	Apical dominance involves ____________ more concentrated in roots and ___________ more concentrated in shoot tips.
		A)	auxins, cytokinins
		B)	cytokinins, auxins
		C)	gibberellins, auxins
		D)	cytokinins, gibberellins


7	What hormone is responsible for the ripening of fruit?
		A)	abscisic acid
		B)	gibberellins
		C)	cytokinins
		D)	ethylene


8	What hormone inhibits the growth-stimulating effects of the auxins?
		A)	abscisic acid
		B)	gibberellins
		C)	cytokinins
		D)	ethylene


9	What pigment is the photoreceptor for auxin, and is thus responsible for phototropism?
		A)	chlorophyll a
		B)	chlorophyll b
		C)	xanthophyll
		D)	flavin


10	True or false. The mechanism for gravitropism clearly involves amyloplasts that function as gravity detectors.
		A)	True
		B)	False


11	What hormone(s) is/are responsible for thigmotropism? auxin
		A)	auxin
		B)	cytokinin
		C)	ethylene
		D)	both a and b
		E)	both a and c


12	True or false. Thigmonastic movements can be protective.
		A)	True
		B)	False


13	Thigmonastic movements result from ______________.
		A)	reversible changes in turgor pressure
		B)	increased cell size through acidification
		C)	Both a and b are correct.
		D)	None of these is correct.


14	When a prayer plant changes the orientation of its leaves it is said to be _____________.
		A)	thigmotropic
		B)	phototropic
		C)	thigmonastic
		D)	photonastic


15	What type of plants flower regardless of length of day?
		A)	long-day plants
		B)	day-neutral plants
		C)	short-day plants
		D)	intermediate-day plants


16	What pigment is responsible for photoperiodism?
		A)	cytochrome
		B)	phytochrome
		C)	carotenoid
		D)	chlorophyll


17	___________ is the rapid elongation of seedlings to reach light before exhausting their food resources.
		A)	Senescence
		B)	Dormancy
		C)	Etiolation
		D)	Germination


18	True or false. Only photoperiodism can trigger dormancy.
		A)	True
		B)	False


19	Environmentally controlled resynchronization of a circadian rhythm is called ______________.
		A)	entrainment
		B)	synchrony
		C)	heliotropism
		D)	photoperiodism


20	True or false. Heliotropic plants maximize sun exposure to warm pollinators as well as for photosynthesis.
		A)	True
		B)	False


21	What plant communication molecule(s) help(s) regulate development by inactivating certain genes?
		A)	salicylic acid
		B)	methyl groups
		C)	jasmonic acid
		D)	brassinolide

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