Question 1

Experiments on the positive phototropic response of plants indicate that ________.

Accepted Answer

A)   light destroys auxin
B)   auxin moves down the plant apoplastically
C)   auxin is synthesised in the area where the stem bends
D)   auxin can move to the shady side of the stemE) A) and D)
F) B) and C)

Question 2

You have a small tree in your yard that is the height that you want it, but does not have as many branches as you want. How can you prune it to trigger it to increase the number of branches?

Accepted Answer

A)   Cut off the leaves at the ends of several branches.
B)   Cut off the tips of the main shoots.
C)   Cut off lower branches.
D)   Cut off the leaves at the base of most of the branches.E) A) and D)
F) A) and C)

Question 3

Apical dominance in plants is under the control of ________.

Accepted Answer

A)   sugar
B)   various plant hormones
C)   cell division
D)   sugar and various plant hormonesE) B) and D)
F) All of the above

Question 4

________ prevents seeds from germinating until conditions are favourable for the growth of the plant.

Accepted Answer

A)   Ethylene
B)   Zeaxanthin
C)   Gibberellin
D)   Abscisic acidE) None of the above
F) C) and D)

Question 5

Which event during the evolution of land plants favoured the synthesis of secondary compounds?

Accepted Answer

A)   the greenhouse effect throughout the Devonian period
B)   the reverse-greenhouse effect during the Carboniferous period
C)   the association of the roots of land plants and fungi
D)   the rise of herbivoryE) A) and C)
F) C) and D)

Question 6

The detector of light during de-etiolation (greening)  of a tomato plant is (are)  ________.

Accepted Answer

A)   carotenoids
B)   xanthophylls
C)   phytochrome
D)   auxinE) A) and B)
F) A) and C)

Question 7

Plants often use changes in day length (photoperiod)  to trigger events such as dormancy and flowering. It is logical that plants have evolved this mechanism because photoperiod changes ________.

Accepted Answer

A)   are more predictable than air temperature changes
B)   predict moisture availability
C)   are modified by soil temperature changes
D)   can reset the biological clockE) A) and B)
F) B) and C)

Question 8

The rapid leaf movements resulting from a response to touch (thigmotropism)  primarily involve ________.

Accepted Answer

A)   potassium channels
B)   nervous tissue
C)   aquaporins
D)   stress proteinsE) B) and C)
F) A) and D)

Question 9

In the autumn, the leaves of some trees change colour. This happens because chlorophyll breaks down and the accessory pigments become visible. What hormone is responsible for this?

Accepted Answer

A)   phototropin
B)   abscisic acid
C)   cytokinin
D)   ethyleneE) None of the above
F) A) and C)

Question 10

In extremely cold regions, woody species may survive freezing temperatures by ________.

Accepted Answer

A)   emptying water from the vacuoles to prevent freezing
B)   decreasing the numbers of phospholipids in cell membranes
C)   decreasing the fluidity of all cellular membranes
D)   increasing cytoplasmic levels of specific solute concentrations, such as sugarsE) A) and B)
F) A) and C)

Question 11

Plant hormonal regulation differs from animal hormonal regulation in that ________.

Accepted Answer

A)   there are no dedicated hormone-producing organs in plants as there are in animals
B)   all production of hormones is local in plants with little long-distance transport
C)   only animal hormone concentrations are developmentally regulated
D)   only animal hormones may have either external or internal receptorsE) A) and D)
F) None of the above

Question 12

Seed packets give a recommended planting depth for the enclosed seeds. The most likely reason some seeds are to be covered with only ½ centimetre of soil is that the ________.

Accepted Answer

A)   seedlings do not have an etiolation response
B)   seeds require light to germinate
C)   seeds require a higher temperature to germinate
D)   seeds are very sensitive to waterloggingE) A) and B)
F) All of the above

Question 13

Suppose you laid a seedling on its side so that the root was parallel to the ground as shown in the figure. Several hours after the change in position, where in the root cells, position A, B, or C in the figure, would you find the amyloplasts?

Accepted Answer

A)   A
B)   B
C)   C
D)   A and CE) None of the above
F) A) and B)

Question 14

A plant scientist was hired by a greenhouse operator to devise a way to force iris plants to bloom in the short days of winter. Iris normally blooms as a long-day (short-night)  plant. Which of the following has the best chance of creating iris blooms in winter?

Accepted Answer

A)   Artificially increase the period of darkness in the greenhouse.
B)   Increase the temperature to more closely follow summer temperatures.
C)   Alternate four hours of darkness with four hours of light repeatedly over each 24-hour period.
D)   Interrupt the long winter nights with a brief period of light.E) All of the above
F) C) and D)

Question 15

Which type of mutant would be most likely to produce a bushier phenotype?

Accepted Answer

A)   auxin overproducer
B)   strigolactone overproducer
C)   cytokinin underproducer
D)   strigolactone underproducerE) B) and C)
F) None of the above

Question 16

If you were shipping green bananas to a supermarket thousands of miles away, which of the following chemicals would you want to eliminate from the plants' environment?

Accepted Answer

A)   carbon dioxide
B)   cytokinins
C)   ethylene
D)   auxinE) A) and B)
F) A) and C)

Question 17

Most scientists agree that global warming is underway; thus, it is important to know how plants respond to heat stress. Which of the following would be a useful line of inquiry to try and improve plant response and survival to heat stress?

Accepted Answer

A)   the production of heat-stable carbohydrates
B)   increased production of heat-shock proteins
C)   the opening of stomata to increase evaporational heat loss
D)   protoplast fusion experiments with xerophytic plantsE) B) and C)
F) A) and C)

Question 18

Plant hormones ________.

Accepted Answer

A)   in plant cells naturally exist in very large amounts
B)   change their shape in response to stimulus
C)   are unable to move from one cell to another
D)   affect only cells with the appropriate receptorE) A) and B)
F) C) and D)

Question 19

Auxin enhances cell elongation in all of these ways except

Accepted Answer

A)   increased uptake of solutes.
B)   gene activation.
C)   acid-induced denaturation of cell wall proteins.
D)   cell wall loosening.E) B) and C)
F) A) and D)

Question 20

A gardener in Canada wants to surprise his mother on her birthday and make her favourite hibiscus bush flower in May instead of at the end of June. The bush is growing in the greenhouse. Which of the following might make the hibiscus bush flower early?

Accepted Answer

A)   grafting leaves of a hibiscus that was exposed to long nights
B)   grafting leaves of a hibiscus that was exposed to short nights
C)   exposing flower buds of the hibiscus bush to long nights
D)   exposing flower buds of the hibiscus bush to short nightsE) B) and C)
F) A) and B)

Exam 39: Plant Responses to Internal and External Signals

Plant hormonal regulation differs from animal hormonal regulation in that ________.

Correct AnswerverifiedShow Answer

In the autumn, the leaves of some trees change colour. This happens because chlorophyll breaks down and the accessory pigments become visible. What hormone is responsible for this?

Correct AnswerverifiedShow Answer

Seed packets give a recommended planting depth for the enclosed seeds. The most likely reason some seeds are to be covered with only ½ centimetre of soil is that the ________.

Correct AnswerverifiedShow Answer

In extremely cold regions, woody species may survive freezing temperatures by ________.

Correct AnswerverifiedShow Answer

________ prevents seeds from germinating until conditions are favourable for the growth of the plant.

Correct AnswerverifiedShow Answer

Which event during the evolution of land plants favoured the synthesis of secondary compounds?

Correct AnswerverifiedShow Answer

A plant scientist was hired by a greenhouse operator to devise a way to force iris plants to bloom in the short days of winter. Iris normally blooms as a long-day (short-night) plant. Which of the following has the best chance of creating iris blooms in winter?

Correct AnswerverifiedShow Answer

If you were shipping green bananas to a supermarket thousands of miles away, which of the following chemicals would you want to eliminate from the plants' environment?

Correct AnswerverifiedShow Answer

Suppose you laid a seedling on its side so that the root was parallel to the ground as shown in the figure. Several hours after the change in position, where in the root cells, position A, B, or C in the figure, would you find the amyloplasts?

Correct AnswerverifiedShow Answer

Most scientists agree that global warming is underway; thus, it is important to know how plants respond to heat stress. Which of the following would be a useful line of inquiry to try and improve plant response and survival to heat stress?

Correct AnswerverifiedShow Answer

Apical dominance in plants is under the control of ________.

Correct AnswerverifiedShow Answer

Plant hormones ________.

Correct AnswerverifiedShow Answer

A gardener in Canada wants to surprise his mother on her birthday and make her favourite hibiscus bush flower in May instead of at the end of June. The bush is growing in the greenhouse. Which of the following might make the hibiscus bush flower early?

Correct AnswerverifiedShow Answer

Auxin enhances cell elongation in all of these ways except

Correct AnswerverifiedShow Answer

The rapid leaf movements resulting from a response to touch (thigmotropism) primarily involve ________.

Correct AnswerverifiedShow Answer

Plants often use changes in day length (photoperiod) to trigger events such as dormancy and flowering. It is logical that plants have evolved this mechanism because photoperiod changes ________.

Correct AnswerverifiedShow Answer

The detector of light during de-etiolation (greening) of a tomato plant is (are) ________.

Correct AnswerverifiedShow Answer

Experiments on the positive phototropic response of plants indicate that ________.

Correct AnswerverifiedShow Answer

You have a small tree in your yard that is the height that you want it, but does not have as many branches as you want. How can you prune it to trigger it to increase the number of branches?

Correct AnswerverifiedShow Answer

Which type of mutant would be most likely to produce a bushier phenotype?

Correct AnswerverifiedShow Answer

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