Question 1

Application of herbicides may have unintended consequences because

Accepted Answer

A) different types of plants respond differently to the same herbicide. 
B) plants may increase or decrease the production of hormones in order to avoid the effect of herbicides. 
C) plants may concentrate the herbicides in their fruits so that they can be released from the plant. 
D) plants create new mutations to avoid herbicides, and those new mutations may have unintended consequences. 
A) different types of plants respond differently to the same herbicide. 
B) plants may increase or decrease the production of hormones in order to avoid the effect of herbicides. 
C) plants may concentrate the herbicides in their fruits so that they can be released from the plant. 
D) plants create new mutations to avoid herbicides, and those new mutations may have unintended consequences.

Question 2

About how many gibberellins have been identified in plants?

Accepted Answer

A) one 
B) five 
C) over one hundred 
D) thousands 
A) one 
B) five 
C) over one hundred 
D) thousands

Question 3

Which of the following substances induces "bolting," the rapid elongation of a plant stem?

Accepted Answer

A) a gibberellin 
B) abscisic acid 
C) ethylene 
D) phytochrome 
A) a gibberellin 
B) abscisic acid 
C) ethylene 
D) phytochrome

Question 4

Mimosa plants spread their leaflets during the day and fold them at night. You decide to design an experiment to test whether Mimosa's leaf movements are controlled by a biological clock. Which of the following experiments would be the best test of your hypothesis?

Accepted Answer

A) Growing the plant indoors and turning the lights on in the middle of the night. If a biological clock is controlling leaf movement, the leaves will open. 
B) Putting the plant in a dark closet in the middle of the day. If the leaves close, a biological clock mechanism is ruled out. 
C) Subjecting the plant to a flash of red light in the middle of the night. If the leaves open at the usual time the next morning, a biological clock mechanism is ruled out. 
D) Putting the plant in a dark closet at nightfall. Check on the plant in the morning about 10 hours later, while the plant is still in the closet. If the leaves are open, a biological clock is indicated. 
A) Growing the plant indoors and turning the lights on in the middle of the night. If a biological clock is controlling leaf movement, the leaves will open. 
B) Putting the plant in a dark closet in the middle of the day. If the leaves close, a biological clock mechanism is ruled out. 
C) Subjecting the plant to a flash of red light in the middle of the night. If the leaves open at the usual time the next morning, a biological clock mechanism is ruled out. 
D) Putting the plant in a dark closet at nightfall. Check on the plant in the morning about 10 hours later, while the plant is still in the closet. If the leaves are open, a biological clock is indicated.

Question 5

Plants grow toward light through the action of

Accepted Answer

A) hormones. 
B) nerves. 
C) solar energy. 
D) chloroplasts. 
A) hormones. 
B) nerves. 
C) solar energy. 
D) chloroplasts.

Question 6

Iris is a long-day plant that normally flowers in the spring. Which of the following regimens would be the most effective in making an iris bloom in late fall?

Accepted Answer

A) interrupting the plant's nights at 2:00 am with a flash of far-red light 
B) interrupting the plant's nights at 2:00 am with a flash of red light followed by a flash of far-red light 
C) interrupting the plant's nights at 2:00 am with a red flash, then a far-red flash, then a red flash 
D) interrupting the plant's days at 2:00 pm by putting it in the dark 
A) interrupting the plant's nights at 2:00 am with a flash of far-red light 
B) interrupting the plant's nights at 2:00 am with a flash of red light followed by a flash of far-red light 
C) interrupting the plant's nights at 2:00 am with a red flash, then a far-red flash, then a red flash 
D) interrupting the plant's days at 2:00 pm by putting it in the dark

Question 7

What dense storage granules in plant cells are thought to contribute to gravitropism?

Accepted Answer

A) starch 
B) cellulose 
C) proteins 
D) chlorophyll 
A) starch 
B) cellulose 
C) proteins 
D) chlorophyll

Question 8

Under what conditions would you expect a plant to have the highest concentration of abscisic acid?

Accepted Answer

A) in a wet tropical rain forest 
B) in a cool environment after a heavy rain 
C) in a houseplant growing in low light conditions 
D) in a desert after a long drought 
A) in a wet tropical rain forest 
B) in a cool environment after a heavy rain 
C) in a houseplant growing in low light conditions 
D) in a desert after a long drought

Question 9

After reading the paragraphs below, answer the questions that follow.
A student taking a plant physiology class is interested in investigating what will happen if the apical bud is removed from a growing plant and supplementary hormones are introduced.
He set up his experiment with two groups of plants of the same species. In groups A and B, the apical buds were removed and the cut apical ends were wrapped with hormone-impregnated cotton. The plants were observed over a five-week period for growth and development. In group A, many axillary buds and leaves appeared along the sides of the stem, but the plants had minimal root growth. In group B, minimal growth occurred in the shoot and roots, and no axillary buds formed.
-What hormone was in the cotton used to wrap the apical ends of the group A plants?

Accepted Answer

A) cytokinin 
B) giberellin 
C) ethylene 
D) auxin 
A) cytokinin 
B) giberellin 
C) ethylene 
D) auxin

Question 10

Which of the following statements about plant hormones is true?

Accepted Answer

A) Plant hormones are produced in very small concentrations. 
B) Plant hormones mainly affect reproductive processes. 
C) Individual hormones typically have single, specific effects. 
D) Plant hormones play a vital role in photosynthesis. 
A) Plant hormones are produced in very small concentrations. 
B) Plant hormones mainly affect reproductive processes. 
C) Individual hormones typically have single, specific effects. 
D) Plant hormones play a vital role in photosynthesis.

Question 11

-Which plant in Went's experiment shows auxin stimulating elongation in the left side of the plant only?

Accepted Answer

A) plant A 
B) plant B 
C) plant C 
D) plant D 
A) plant A 
B) plant B 
C) plant C 
D) plant D

Question 12

A plant's first line of defense against infection is

Accepted Answer

A) Avr genes. 
B) its epidermis. 
C) R genes. 
D) salicylic acid. 
A) Avr genes. 
B) its epidermis. 
C) R genes. 
D) salicylic acid.

Question 13

Which of the following lists the events leading to leaf fall in deciduous trees in the correct order?

Accepted Answer

A) formation of abscission layer, increase in ethylene levels, decrease in auxin levels 
B) shortening days, increase in ethylene production, formation of abscission layer 
C) shortening days, formation of abscission layer, decrease in ethylene levels 
D) decrease in ethylene levels, shortening days, formation of abscission layer 
A) formation of abscission layer, increase in ethylene levels, decrease in auxin levels 
B) shortening days, increase in ethylene production, formation of abscission layer 
C) shortening days, formation of abscission layer, decrease in ethylene levels 
D) decrease in ethylene levels, shortening days, formation of abscission layer

Question 14

Bush beans grow as small bushes rather than as vines because their internodes are short and they branch close to the apical meristem. Which of the following substances, if applied to a bush bean, might cause it to grow as a vine?

Accepted Answer

A) a cytokinin 
B) a gibberellin 
C) abscisic acid 
D) ethylene 
A) a cytokinin 
B) a gibberellin 
C) abscisic acid 
D) ethylene

Question 15

Which class of hormones produced in the roots of plants promotes cell division and growth and retards the aging of flowers and leaves?

Accepted Answer

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

Question 16

-In the figure, the shoot emerged through the soil toward the light rather than growing down in the direction of the roots due to

Accepted Answer

A) thigmotropism. 
B) phototropism. 
C) gravitropism. 
D) circadian rhythm. 
A) thigmotropism. 
B) phototropism. 
C) gravitropism. 
D) circadian rhythm.

Question 17

Which of the following processes underlies the thigmotropic behavior of a green bean tendril?

Accepted Answer

A) rotation of the tendril in response to photoperiod 
B) rotation of the tendril in response to a biological clock 
C) extra proliferation of cells on the shaded side of the tendril 
D) slower growth on the side where an object is touching the tendril 
A) rotation of the tendril in response to photoperiod 
B) rotation of the tendril in response to a biological clock 
C) extra proliferation of cells on the shaded side of the tendril 
D) slower growth on the side where an object is touching the tendril

Question 18

One experiment in phototropism involved cutting off the tips of grass seedlings before exposing them to light from one side. The decapitated seedlings did not bend toward the light. A valid conclusion from this experiment would be that

Accepted Answer

A) plants cannot engage in photosynthesis without the tip of the plant. 
B) light is perceived by the tip of grass plants. 
C) a foil cover over the tip of the seedlings would cause them to bend. 
D) hormones are produced in all parts of the plant. 
A) plants cannot engage in photosynthesis without the tip of the plant. 
B) light is perceived by the tip of grass plants. 
C) a foil cover over the tip of the seedlings would cause them to bend. 
D) hormones are produced in all parts of the plant.

Exam 33: Control Systems in Plants

Application of herbicides may have unintended consequences because

About how many gibberellins have been identified in plants?

Which of the following substances induces "bolting," the rapid elongation of a plant stem?

Mimosa plants spread their leaflets during the day and fold them at night. You decide to design an experiment to test whether Mimosa's leaf movements are controlled by a biological clock. Which of the following experiments would be the best test of your hypothesis?

Plants grow toward light through the action of

Iris is a long-day plant that normally flowers in the spring. Which of the following regimens would be the most effective in making an iris bloom in late fall?

What dense storage granules in plant cells are thought to contribute to gravitropism?

Under what conditions would you expect a plant to have the highest concentration of abscisic acid?

Which of the following statements about plant hormones is true?

-Which plant in Went's experiment shows auxin stimulating elongation in the left side of the plant only?

A plant's first line of defense against infection is

Which of the following lists the events leading to leaf fall in deciduous trees in the correct order?

Bush beans grow as small bushes rather than as vines because their internodes are short and they branch close to the apical meristem. Which of the following substances, if applied to a bush bean, might cause it to grow as a vine?

Which class of hormones produced in the roots of plants promotes cell division and growth and retards the aging of flowers and leaves?

-In the figure, the shoot emerged through the soil toward the light rather than growing down in the direction of the roots due to

Which of the following processes underlies the thigmotropic behavior of a green bean tendril?

One experiment in phototropism involved cutting off the tips of grass seedlings before exposing them to light from one side. The decapitated seedlings did not bend toward the light. A valid conclusion from this experiment would be that

Biology: Exploring Life

The Chemical Basis of Life

The Molecules of Cells

A Tour of the Cell

The Working Cell

How Cells Harvest Chemical Energy

Photosynthesis: Using Light to Make Food

The Cellular Basis of Reproduction and Inheritance

Patterns of Inheritance

Molecular Biology of the Gene

How Genes Are Controlled

DNA Technology and Genomics

How Populations Evolve

The Origin of Species

Tracing Evolutionary History

Microbial Life: Prokaryotes and Protists

The Evolution of Plant and Fungal Diversity

The Evolution of Invertebrate Diversity

The Evolution of Vertebrate Diversity

Unifying Concepts of Animal Structure and Function

Nutrition and Digestion

Gas Exchange

Circulation

the Immune System

Control of Body Temperature and Water Balance

Hormones and the Endocrine System

Reproduction and Embryonic Development

Nervous Systems

the Senses

How Animals Move

Plant Structure, Growth, and Reproduction

Plant Nutrition and Transport

the Biosphere: an Introduction to Earths Diverse Environments

Behavioral Adaptations to the Environment

Population Ecology

Communities and Ecosystems

Conservation Biology

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