Question 1

What term refers to seasonal changes in the relative lengths of night and day?

Accepted Answer

A) photoperiod 
B) circadian rhythm 
C) gravitropism 
D) phototaxis 
A) photoperiod 
B) circadian rhythm 
C) gravitropism 
D) phototaxis

Question 2

Which of the following is one adaptive advantage for deciduous plants that lose their leaves during the winter?

Accepted Answer

A) It prevents water loss from leaves when soil water is unavailable due to freezing. 
B) Production of new leaves each spring is more efficient than supporting old leaves all winter. 
C) If leaves are damaged by frost, the tree will die. 
D) A layer of leaves on the ground helps keep plant roots warm. 
A) It prevents water loss from leaves when soil water is unavailable due to freezing. 
B) Production of new leaves each spring is more efficient than supporting old leaves all winter. 
C) If leaves are damaged by frost, the tree will die. 
D) A layer of leaves on the ground helps keep plant roots warm.

Question 3

Fall is coming, with the prospect of frost, so you decide to pick the last tomatoes on the vine even though they are still green. If you wanted to ripen these tomatoes, which method would be most effective?

Accepted Answer

A) Put all the green tomatoes in a closed paper bag. 
B) Put the green tomatoes in a dark closet, but with a flash of light about every 4 hours. 
C) Put the green tomatoes in a plastic bag with an overripe apple. 
D) Store each green tomato in a separate plastic bag and put them in the dark. 
A) Put all the green tomatoes in a closed paper bag. 
B) Put the green tomatoes in a dark closet, but with a flash of light about every 4 hours. 
C) Put the green tomatoes in a plastic bag with an overripe apple. 
D) Store each green tomato in a separate plastic bag and put them in the dark.

Question 4

Plant cells treated with auxin would not be able to enlarge under which of the following conditions?

Accepted Answer

A) lack of light for growing 
B) presence of other hormones in the plant 
C) absence of lysosomes in the plant cells 
D) inability of the cell to take up water 
A) lack of light for growing 
B) presence of other hormones in the plant 
C) absence of lysosomes in the plant cells 
D) inability of the cell to take up water

Question 5

A biologist interested in determining which plant organs (stems, buds, leaves, etc.)are responsible for sensing photoperiod might perform which of the following experiments?

Accepted Answer

A) Remove the apical meristems from different parts of the plant. 
B) Measure auxin levels in different parts of the plant before and after exposure to light. 
C) Cover different plant organs with a foil covering to prevent light exposure. 
D) Expose the plants to different wavelengths of light. 
A) Remove the apical meristems from different parts of the plant. 
B) Measure auxin levels in different parts of the plant before and after exposure to light. 
C) Cover different plant organs with a foil covering to prevent light exposure. 
D) Expose the plants to different wavelengths of light.

Question 6

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 B plants?

Accepted Answer

A) cytokinin 
B) giberellin 
C) abscisic acid 
D) auxin 
A) cytokinin 
B) giberellin 
C) abscisic acid 
D) auxin

Question 7

Christmas cactus is a short-day plant that usually blooms in the winter. Which of the following strategies might induce it to bloom for the 4th of July?

Accepted Answer

A) putting it in a cool, well-lighted place from time to time during June 
B) leaving it in a dark closet all night and part of each morning during June 
C) putting it in a dark closet for a short time every afternoon during June 
D) exposing it to light several times during each night in June 
A) putting it in a cool, well-lighted place from time to time during June 
B) leaving it in a dark closet all night and part of each morning during June 
C) putting it in a dark closet for a short time every afternoon during June 
D) exposing it to light several times during each night in June

Question 8

Which of the following plant responses is affected by photoperiod?

Accepted Answer

A) gravitropism 
B) apical dominance 
C) onset of dormancy 
D) cell division 
A) gravitropism 
B) apical dominance 
C) onset of dormancy 
D) cell division

Question 9

There is concern over the use of 2,4-D, a synthetic plant hormone, as a weed killer because the by-product dioxin

Accepted Answer

A) can cause irreversible mutations in crop plants. 
B) causes massive fish kills when it gets into lakes and streams. 
C) can cause birth defects and leukemia in mammals. 
D) weakens the shells of the eggs of predatory birds, resulting in the death of their offspring. 
A) can cause irreversible mutations in crop plants. 
B) causes massive fish kills when it gets into lakes and streams. 
C) can cause birth defects and leukemia in mammals. 
D) weakens the shells of the eggs of predatory birds, resulting in the death of their offspring.

Question 10

A student wanted to plant an avocado seed to try to grow an avocado plant, but she could not tell which end of the seed was the bottom and which was the top. She asked her friends what she should do. Which one has the best response?

Accepted Answer

A) One friend said it doesn't matter in which direction the seed is planted as long as there is a strong light on the soil, since the shoots will seek the light and turn the seed right side up. 
B) One friend said to put the seed in in any direction, because as the seed is watered, it will be able to detect the direction the water is coming from and point the shoots that way. 
C) One friend suggested a compromise: Put the seed sideways, since gravity will ensure that the shoots grow up and the roots grow down. 
D) One friend said just to put the seed in one direction or the other, because it will only sprout if it is in the right direction, and there's a 50/50 chance that it will be in the right orientation. 
A) One friend said it doesn't matter in which direction the seed is planted as long as there is a strong light on the soil, since the shoots will seek the light and turn the seed right side up. 
B) One friend said to put the seed in in any direction, because as the seed is watered, it will be able to detect the direction the water is coming from and point the shoots that way. 
C) One friend suggested a compromise: Put the seed sideways, since gravity will ensure that the shoots grow up and the roots grow down. 
D) One friend said just to put the seed in one direction or the other, because it will only sprout if it is in the right direction, and there's a 50/50 chance that it will be in the right orientation.

Question 11

In many grocery stores, fresh fruits are sold in plastic bags dotted with holes so that they will not overripen. The main function of the holes is to

Accepted Answer

A) permit the fruit to drain after being washed. 
B) facilitate diffusion of ethylene away from the fruit. 
C) prevent buildup of CO₂. 
D) facilitate diffusion of O₂ to the fruit. 
A) permit the fruit to drain after being washed. 
B) facilitate diffusion of ethylene away from the fruit. 
C) prevent buildup of CO₂. 
D) facilitate diffusion of O₂ to the fruit.

Question 12

Citrus fruit has always been distributed from areas where the fruit is grown to other parts of the country, often by train. In the early 1900s train cars were heated with coal, and it was believed that this heat helped ripen the fruit. Imagine the surprise of growers and suppliers when fruit that arrived in new boxcars heated by steam arrived unripe. Why did the fruit no longer ripen?

Accepted Answer

A) The length of time needed to ripen the fruit was met by slow-moving older trains; newer steam-powered locomotives arrived before the fruit ripened. 
B) Ethylene, a by-product of coal burning, ripened the fruit in the cars with the coal stove but was absent from the steam-powered trains. 
C) The light from the coal-burning stoves caused the fruits to experience short nights, so they ripened. 
D) The steam prevented the buildup of abscisic acid, which is needed to ripen fruit. 
A) The length of time needed to ripen the fruit was met by slow-moving older trains; newer steam-powered locomotives arrived before the fruit ripened. 
B) Ethylene, a by-product of coal burning, ripened the fruit in the cars with the coal stove but was absent from the steam-powered trains. 
C) The light from the coal-burning stoves caused the fruits to experience short nights, so they ripened. 
D) The steam prevented the buildup of abscisic acid, which is needed to ripen fruit.

Question 13

If the auxin that is produced by an apical meristem is transported in equal amounts down all sides of a twig, the twig will probably

Accepted Answer

A) elongate evenly. 
B) branch near its tip. 
C) flower. 
D) bend away from the apical meristem. 
A) elongate evenly. 
B) branch near its tip. 
C) flower. 
D) bend away from the apical meristem.

Question 14

The most reliable way to stimulate branching in a plant is to

Accepted Answer

A) apply auxin to the axillary buds. 
B) remove the terminal bud. 
C) give short-day light treatments. 
D) add extra fertilizer. 
A) apply auxin to the axillary buds. 
B) remove the terminal bud. 
C) give short-day light treatments. 
D) add extra fertilizer.

Question 15

Shoot branching is controlled mainly by the interaction of

Accepted Answer

A) auxins and gibberellins. 
B) auxins and cytokinins. 
C) gibberellins and cytokinins. 
D) cytokinins and abscisic acid. 
A) auxins and gibberellins. 
B) auxins and cytokinins. 
C) gibberellins and cytokinins. 
D) cytokinins and abscisic acid.

Question 16

Which of the following growth responses causes the shoots of a plant grown in the dark to grow upward?

Accepted Answer

A) phototropism 
B) thigmotropism 
C) photoperiodism 
D) gravitropism 
A) phototropism 
B) thigmotropism 
C) photoperiodism 
D) gravitropism

Question 17

Which of the following hormones might induce seeds treated with it to break dormancy?

Accepted Answer

A) an auxin 
B) a cytokinin 
C) a gibberellin 
D) ethylene 
A) an auxin 
B) a cytokinin 
C) a gibberellin 
D) ethylene

Question 18

Synthetic auxins are used commercially

Accepted Answer

A) to promote seed germination. 
B) to promote flowering in ornamental crops. 
C) to promote side branching to produce bushier crops. 
D) as a broadleaf weed killer. 
A) to promote seed germination. 
B) to promote flowering in ornamental crops. 
C) to promote side branching to produce bushier crops. 
D) as a broadleaf weed killer.

Question 19

Which of the following statements concerning biological clocks is false?

Accepted Answer

A) Innate circadian rhythms generally differ slightly from a 24-hour period. 
B) Circadian rhythms occur with or without external stimuli. 
C) Biological clocks are strongly influenced by external temperatures. 
D) Movement of plants long distances very quickly induces a kind of plant "jet lag." 
A) Innate circadian rhythms generally differ slightly from a 24-hour period. 
B) Circadian rhythms occur with or without external stimuli. 
C) Biological clocks are strongly influenced by external temperatures. 
D) Movement of plants long distances very quickly induces a kind of plant "jet lag."

Question 20

What stimulates germination of desert plant seeds after a hard rain?

Accepted Answer

A) production of auxins 
B) removal of abscisic acid 
C) cooler temperatures 
D) activation of cytokinins 
A) production of auxins 
B) removal of abscisic acid 
C) cooler temperatures 
D) activation of cytokinins

Exam 33: Control Systems in Plants

What term refers to seasonal changes in the relative lengths of night and day?

Which of the following is one adaptive advantage for deciduous plants that lose their leaves during the winter?

Fall is coming, with the prospect of frost, so you decide to pick the last tomatoes on the vine even though they are still green. If you wanted to ripen these tomatoes, which method would be most effective?

Plant cells treated with auxin would not be able to enlarge under which of the following conditions?

A biologist interested in determining which plant organs (stems, buds, leaves, etc.)are responsible for sensing photoperiod might perform which of the following experiments?

Christmas cactus is a short-day plant that usually blooms in the winter. Which of the following strategies might induce it to bloom for the 4th of July?

Which of the following plant responses is affected by photoperiod?

There is concern over the use of 2,4-D, a synthetic plant hormone, as a weed killer because the by-product dioxin

A student wanted to plant an avocado seed to try to grow an avocado plant, but she could not tell which end of the seed was the bottom and which was the top. She asked her friends what she should do. Which one has the best response?

In many grocery stores, fresh fruits are sold in plastic bags dotted with holes so that they will not overripen. The main function of the holes is to

If the auxin that is produced by an apical meristem is transported in equal amounts down all sides of a twig, the twig will probably

The most reliable way to stimulate branching in a plant is to

Shoot branching is controlled mainly by the interaction of

Which of the following growth responses causes the shoots of a plant grown in the dark to grow upward?

Which of the following hormones might induce seeds treated with it to break dormancy?

Synthetic auxins are used commercially

Which of the following statements concerning biological clocks is false?

What stimulates germination of desert plant seeds after a hard rain?

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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