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Chapter 39: Plant Responses to Internal and External Signals
 
Chapter Quiz
 

Chapter Quiz


1 .       A conformational change in a substance called phytochrome _____. (Concept 39.1E-Book) [Hint]

 causes a plant to bend toward light
 triggers fruit drop
 leads to de-etoliation
 is responsible for gravitropism
 causes changes in a plant in response to stresses such as water shortage
2 .       Growth that results in curvatures of whole plant organs toward or away from stimuli is called _____. (Concept 39.2E-Book) [Hint]

 gravitropism
 phototropism
 thigmotropism
 heliotropism
 all of the above
3 .       You are interested in determining what part of a plant is actually sensitive to light for phototropism. A good first experiment would be to _____. (Concept 39.2E-Book) [Hint]

 remove the apical meristem and apply auxin before beginning light treatments
 shine light from one side only. Then measure the auxin diffusing down the stem on the light and the shaded sides
 cover one part (for instance, the tip or base) before beginning light treatments
 spray auxin on just one part of the plant at a time to determine which one stimulates flowering
 try light treatments of different colors (first blue, then yellow, then green) to see which promotes flowering the fastest
4 .       The immediate, direct effect of auxin in cell elongation, according to the acid growth hypothesis, is to _____. (Concept 39.2E-Book) [Hint]

 increase the hydrostatic pressure in cells, stretching their walls
 activate ATP-driven proton (H+) pumps
 shift the pH and thus activate enzymes that break the hydrogen bonds
 move water into vacuoles
 activate the synthesis of new cytoplasm
5 .       A graduate student growing plant cells in a laboratory dish wants them to _____; therefore, the student treats them with cytokinins. (Concept 39.2E-Book) [Hint]

 enlarge
 become dormant
 grow roots
 produce auxin
 divide
6 .       A callus will develop roots if you use a _____ auxin concentration and a _____ cytokinin concentration in the medium. (Concept 39.2E-Book) [Hint]

 high ... high
 high ... low
 low ... high
 low ... low
 low ... high or low
7 .       In shoots, branching is inhibited by _____ from the tip of a growing shoot, but this effect is countered by _____ from the roots. (Concept 39.2E-Book) [Hint]

 cytokinins ... auxin
 gibberellins ... ethylene
 auxin ... cytokinins
 gibberellins ... abscisic acid
 auxin ... abscisic acid
8 .       Which hormone would a florist most likely spray on cut flowers to keep them fresh? (Concept 39.2E-Book) [Hint]

 auxin
 gibberellins
 cytokinins
 brassinosteriods
 ethylene
9 .       As leaf lettuce matures, a tall flowering shoot extends beyond the basal edible leaves. After the plant bolts like this, it no longer produces broad, tasty leaves. Suppose you want to prevent bolting so that you can harvest lettuce longer. You may want to prevent the plant from synthesizing _____. (Concept 39.2E-Book) [Hint]

 abscisic acid
 gibberellins
 cytokinins
 ethylene
 brassinosteroids
10 .       Seeds of many desert plants will not germinate until a heavy rain washes away their _____. (Concept 39.2E-Book) [Hint]

 phytochrome
 abscisic acid
 gibberellins
 auxin
 phytoalexins
11 .       The synthesis and release of abscisic acid in a plant is a response to _____. (Concept 39.2E-Book) [Hint]

 water deficit
 oxygen deprivation
 salt stress
 heat stress
 herbivory
12 .       The triple response to mechanical stress does not involve _____. (Concept 39.2E-Book) [Hint]

 increased stem elongation
 stem thickening
 asymmetric growth
 the inactivation of kinase
 ethylene
13 .       The abscission layer _____. (Concept 39.2E-Book) [Hint]

 causes a shoot to bend toward light
 secretes cytokinin
 is the location of the biological clock in a plant
 detects light and measures the photoperiod
 is where a leaf separates from a stem
14 .       In the autumn, the amount of _____ decreases, rendering the cells of the abscission layer more sensitive to _____. (Concept 39.2E-Book) [Hint]

 ethylene ... auxin
 gibberellin ... abscisic acid
 cytokinin ... abscisic acid
 auxin ... ethylene
 gibberellin ... auxin
15 .       Which one, if any, of these features is not characteristic of ethylene? (Concept 39.2E-Book) [Hint]

 It is an organic compound.
 It is active in small amounts.
 Ethylene is involved in one of the rare examples of a positive feedback loop.
 A burst of ethylene is almost always associated with apoptosis.
 All of the above statements are true regarding ethylene.


16 .       Some seeds require light for germination, which is controlled by the phytochrome system. In which one of the following treatments would germination not occur? (Concept 39.3E-Book) [Hint]

 red light only
 red light followed by far-red light
 far-red light followed by red light
 green light followed by red light
 red light and far-red light together, followed by red light only
17 .       Circadian rhythms are _____. (Concept 39.3E-Book) [Hint]

 responses to the number of hours of daylight
 innate 24-hour cycles of behavior or physiological change
 monthly cycles of behavior or physiological change
 metabolic processes related to the light/dark cycling of the environment
 none of the above
18 .       Photoperiodism is _____. (Concept 39.3E-Book) [Hint]

 the ability to perceive shortwave ultraviolet light
 an attraction to light
 found only in plants
 a physiological response of an organism to alternating light and dark cycles
 an aversion to light
19 .       An Alaskan trapper worried about being attacked by grizzly bears left on the lights in his cabin all the time. Plants just outside the cabin flowered a month early. Which of the following best explains this? (Concept 39.3E-Book) [Hint]

 It was due to phototropism.
 They must have been long-night plants.
 The lights must have emitted far-red light.
 They must have been long-day plants.
 They must have been short-day plants.
20 .       A certain short-day plant flowers when days are less than 12 hours long. Which of the following will cause it to flower? (Concept 39.3E-Book) [Hint]

 a 9-hour night and a 15-hour day with 1 minute of darkness after 7 hours
 an 8-hour day and a 16-hour night with a flash of white light after 8 hours
 a 13-hour night and an 11-hour day with 1 minute of darkness after 6 hours
 a 12-hour day and a 12-hour night with a flash of red light after 6 hours
 alternating 4-hour periods of light and darkness
21 .       A certain plant flowers only if days are shorter than 10 hours. Which of the following will cause it to flower? (Concept 39.2E-Book) [Hint]

 8 hours light, 8 hours dark, flash of red light, 8 hours dark
 12 hours light, 6 hours dark, flash of red light, 6 hours dark
 8 hours light, brief dark period, 8 hours light, 8 hours dark
 8 hours light, 8 hours dark, flash of red light, flash of far-red light, 8 hours dark
 6 hours light, 6 hours dark, 6 hours light, 6 hours dark
22 .       _____ appear to be responsible for gravitropism. (Concept 39.4E-Book) [Hint]

 Statoliths
 Phytoalexins
 Gibberellins
 Cytokinins
 Phytochromes
23 .       A rapid loss of water in specialized cells in the sensitive plant Mimosa pudica causes _____. (Concept 39.4E-Book) [Hint]

 seed germination
 the plant to bend toward light
 stomatal openings, initiating photosynthesis
 stress that results in the production of PR proteins
 leaves to droop
24 .       Inhibiting the growth of shallow roots is a response of plants to _____. (Concept 39.4E-Book) [Hint]

 water deficit
 oxygen deprivation
 salt stress
 heat stress
 herbivory
25 .       The formation of air tubes in submerged roots is an adaptation to _____. (Concept 39.4E-Book) [Hint]

 water deficit
 oxygen deprivation
 salt stress
 heat stress
 cold stress
26 .       When a plant that is not adapted to salty water is exposed to salty water, it will _____. (Concept 39.4E-Book) [Hint]

 lose water rather than absorb it
 thrive
 form air tubes
 synthesize and release abscisic acid
 keep its stomata closed
27 .       The production of organic solutes by plants is a response to _____. (Concept 39.4E-Book) [Hint]

 water deficit
 oxygen deprivation
 salt stress
 heat stress
 herbivory
28 .       Which one of the following describes a plant's response to heat stress? (Concept 39.4E-Book) [Hint]

 production of heat-shock proteins
 closing of stomata
 production of abscisic acid
 production of heat-shock proteins and closing of stomata
 production of heat-shock proteins, closing of stomata, and altering the lipid composition of their membranes
29 .       How are heat-shock proteins thought to work? (Concept 39.4E-Book) [Hint]

 They promote evaporative cooling.
 They help other proteins retain their functional shapes.
 They regulate stomatal opening and closing.
 They facilitate the uptake of water.
 They increase water potential.
30 .       Increasing the proportion of unsaturated fatty acids in their membranes is a response of plants to _____. (Concept 39.4E-Book) [Hint]

 water deficit
 oxygen deprivation
 salt stress
 cold stress
 herbivory
31 .       Increasing the cytoplasmic levels of specific well-tolerated solutes, such as sugars, helps a plant to cope with _____. (Concept 39.4E-Book) [Hint]

 water deficit
 oxygen deprivation
 heat stress
 cold stress
 herbivory
32 .       The production of canavanine is a response of some plants to _____. (Concept 39.5E-Book) [Hint]

 water deficit
 oxygen deprivation
 salt stress
 cold stress
 herbivory
33 .       In at least some species of plants, a leaf damaged by a caterpillar may _____. (Concept 39.5E-Book) [Hint]

 synthesize and release chemicals that attract wasps that prey on the caterpillar
 produce large quantities of heat-shock proteins that discourage foraging
 increase the proportion of unsaturated fatty acids in the membranes
 respond by producing organic solutes that affect water potential
 increase the synthesis and release of abscisic acid, a deterrent to foraging
34 .       The first line of defense against pathogens is _____. (Concept 39.5E-Book) [Hint]

 gene-for-gene recognition
 specific plant disease resistance (R) genes
 production of oligosaccharides
 production of phytoalexines
 physical barrier of the epidermis (or periderm)
35 .       Plant defenses against the herbivores that feed on them include _____. (Concept 39.5E-Book) [Hint]

 poisons such as canavanine
 physical defenses, such as thorns and spines
 distasteful compounds
 chemicals that mimic insect hormones and cause developmental malformations in insects that eat them
 all of the above





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