Question 1

What would happen if the secondary messenger cGMP was blocked in the de-etiolation pathway?

Accepted Answer

A)  Specific protein kinase 1 would be activated, and greening would occur. 
B)  Ca2⁺ channels would not open, and no greening would occur. 
C)  Ca2⁺ channels could open, and specific protein kinase 2 could still be produced. 
D)  No transcription of genes that function in de-etiolation would occur. 
E)  Transcription of de-etiolation genes in the nucleus would not be affected. 
A)  Specific protein kinase 1 would be activated, and greening would occur. 
B)  Ca2⁺ channels would not open, and no greening would occur. 
C)  Ca2⁺ channels could open, and specific protein kinase 2 could still be produced. 
D)  No transcription of genes that function in de-etiolation would occur. 
E)  Transcription of de-etiolation genes in the nucleus would not be affected.

Question 2

Vines in tropical rain forests must grow toward large trees before being able to grow toward the sun. To reach a large tree, the most useful kind of growth movement for a tropical vine presumably would be the opposite of

Accepted Answer

A)  positive thigmotropism. 
B)  positive phototropism. 
C)  positive gravitropism. 
D)  sleep movements. 
E)  circadian rhythms. 
A)  positive thigmotropism. 
B)  positive phototropism. 
C)  positive gravitropism. 
D)  sleep movements. 
E)  circadian rhythms.

Question 3

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)  producing canavanine as a natural antifreeze. 
E)  increasing cytoplasmic levels of specific solute concentrations, such as sugars. 
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)  producing canavanine as a natural antifreeze. 
E)  increasing cytoplasmic levels of specific solute concentrations, such as sugars.

Question 4

Which of the following hormones would never be found in high concentrations in a dormant overwintering flower bud?

Accepted Answer

A)  auxin 
B)  cytokinins 
C)  abscisic acid 
D)  ethylene 
E)  gibberellins 
A)  auxin 
B)  cytokinins 
C)  abscisic acid 
D)  ethylene 
E)  gibberellins

Question 5

Charles and Francis Darwin concluded from their experiments on phototropism by grass seedlings that the part of the seedling that detects the direction of light is the

Accepted Answer

A)  tip of the coleoptile. 
B)  part of the coleoptile that bends during the response. 
C)  base of the coleoptile. 
D)  cotyledon. 
E)  phytochrome in the leaves. 
A)  tip of the coleoptile. 
B)  part of the coleoptile that bends during the response. 
C)  base of the coleoptile. 
D)  cotyledon. 
E)  phytochrome in the leaves.

Question 6

The hormone that helps plants respond to drought is

Accepted Answer

A)  auxin. 
B)  gibberellin. 
C)  cytokinin. 
D)  ethylene. 
E)  abscisic acid. 
A)  auxin. 
B)  gibberellin. 
C)  cytokinin. 
D)  ethylene. 
E)  abscisic acid.

Question 7

The initial response of the root cells of a tomato plant watered with seawater would be to

Accepted Answer

A)  rapidly produce organic solutes in the cytoplasm. 
B)  rapidly expand until the cells burst. 
C)  begin to plasmolyze as water is lost. 
D)  actively transport water from the cytoplasm into the vacuole. 
E)  actively absorb salts from the seawater. 
A)  rapidly produce organic solutes in the cytoplasm. 
B)  rapidly expand until the cells burst. 
C)  begin to plasmolyze as water is lost. 
D)  actively transport water from the cytoplasm into the vacuole. 
E)  actively absorb salts from the seawater.

Question 8

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 synthesized in the area where the stem bends. 
D)  auxin can move to the shady side of the stem. 
E)  auxin is only of secondary importance in the process. 
A)  light destroys auxin. 
B)  auxin moves down the plant apoplastically. 
C)  auxin is synthesized in the area where the stem bends. 
D)  auxin can move to the shady side of the stem. 
E)  auxin is only of secondary importance in the process.

Question 9

Most plants close their stomata at night. What color of light would be most effective in promoting stomatal opening in the middle of the night?

Accepted Answer

A)  red 
B)  far-red 
C)  blue 
D)  red followed by far-red 
E)  far-red followed by blue 
A)  red 
B)  far-red 
C)  blue 
D)  red followed by far-red 
E)  far-red followed by blue

Question 10

Many plants flower in response to day-length cues. Which of the following statements best summarizes this phenomenon?

Accepted Answer

A)  As a rule, short-day plants flower in the summer. 
B)  As a rule, long-day plants flower in the spring or fall. 
C)  Long-day plants flower in response to long days, not short nights. 
D)  Flowering in day-neutral plants is only influenced by day length if there is an exceptionally warm spring. 
E)  Flowering in short-day and long-day plants is controlled by phytochrome. 
A)  As a rule, short-day plants flower in the summer. 
B)  As a rule, long-day plants flower in the spring or fall. 
C)  Long-day plants flower in response to long days, not short nights. 
D)  Flowering in day-neutral plants is only influenced by day length if there is an exceptionally warm spring. 
E)  Flowering in short-day and long-day plants is controlled by phytochrome.

Question 11

Auxin triggers the acidification of cell walls, which results in rapid growth, but also stimulates sustained, long-term cell elongation. What best explains how auxin brings about this dual growth response?

Accepted Answer

A)  Auxin binds to different receptors in different cells. 
B)  Different concentrations of auxin have different effects. 
C)  Auxin causes second messengers to activate both proton pumps on the plasma membrane and certain genes within the same cells. 
D)  The dual effects are due to two different types of auxins that are produced by different genes. 
E)  Other antagonistic hormones modify auxin's effects. 
A)  Auxin binds to different receptors in different cells. 
B)  Different concentrations of auxin have different effects. 
C)  Auxin causes second messengers to activate both proton pumps on the plasma membrane and certain genes within the same cells. 
D)  The dual effects are due to two different types of auxins that are produced by different genes. 
E)  Other antagonistic hormones modify auxin's effects.

Question 12

The plant hormone involved in aging and ripening of fruit is

Accepted Answer

A)  auxin. 
B)  ethylene. 
C)  florigen. 
D)  abscisic acid. 
E)  gibberellin. 
A)  auxin. 
B)  ethylene. 
C)  florigen. 
D)  abscisic acid. 
E)  gibberellin.

Question 13

A long-day plant will flower

Accepted Answer

A)  in the late fall. 
B)  when the night is shorter than a critical value. 
C)  only under artificial light in the summer. 
D)  during short days with proper fertilization. 
E)  regardless of the photoperiod imposed. 
A)  in the late fall. 
B)  when the night is shorter than a critical value. 
C)  only under artificial light in the summer. 
D)  during short days with proper fertilization. 
E)  regardless of the photoperiod imposed.

Question 14

The transduction pathway that activates systemic acquired resistance in plants is initially signaled by

Accepted Answer

A)  antisense RNA. 
B)  Pfr phytochrome. 
C)  salicylic acid. 
D)  abscisic acid. 
E)  red, but not far-red, light. 
A)  antisense RNA. 
B)  Pfr phytochrome. 
C)  salicylic acid. 
D)  abscisic acid. 
E)  red, but not far-red, light.

Question 15

Why are lateral buds often inhibited from sprouting even though a stem may be actively elongating?

Accepted Answer

A)  The cells of lateral buds are more sensitive to auxin than stem cells. 
B)  Lateral buds are high in abscisic acid that prevents elongation. 
C)  Lateral buds are low in gibberellins. 
D)  Stem cells lack receptors for auxin. 
E)  Stem cells can overcome auxin inhibition with high levels of gibberellins. 
A)  The cells of lateral buds are more sensitive to auxin than stem cells. 
B)  Lateral buds are high in abscisic acid that prevents elongation. 
C)  Lateral buds are low in gibberellins. 
D)  Stem cells lack receptors for auxin. 
E)  Stem cells can overcome auxin inhibition with high levels of gibberellins.

Question 16

Seed packets give a recommended planting depth for the enclosed seeds. The most likely reason some seeds are to be covered with only ¼ inch of soil is that the

Accepted Answer

A)  seedlings do not produce a hypocotyl. 
B)  seedlings do not have an etiolation response. 
C)  seeds require light to germinate. 
D)  seeds require a higher temperature to germinate. 
E)  seeds are very sensitive to waterlogging. 
A)  seedlings do not produce a hypocotyl. 
B)  seedlings do not have an etiolation response. 
C)  seeds require light to germinate. 
D)  seeds require a higher temperature to germinate. 
E)  seeds are very sensitive to waterlogging.

Question 17

How does indoleacetic acid affect fruit development?

Accepted Answer

A)  by preventing pollination 
B)  by inhibiting formation of the ovule 
C)  by promoting gene expression in cambial tissue 
D)  by promoting rapid growth of the ovary 
E)  by inducing the formation of brassinosteroids 
A)  by preventing pollination 
B)  by inhibiting formation of the ovule 
C)  by promoting gene expression in cambial tissue 
D)  by promoting rapid growth of the ovary 
E)  by inducing the formation of brassinosteroids

Question 18

A short-day plant will flower only when

Accepted Answer

A)  days are shorter than nights. 
B)  days are shorter than a certain critical value. 
C)  nights are shorter than a certain critical value. 
D)  nights are longer than a certain critical value. 
E)  days and nights are of equal length. 
A)  days are shorter than nights. 
B)  days are shorter than a certain critical value. 
C)  nights are shorter than a certain critical value. 
D)  nights are longer than a certain critical value. 
E)  days and nights are of equal length.

Question 19

The synthesis of which of the following hormones would be a logical first choice in an attempt to produce normal growth in mutant dwarf plants?

Accepted Answer

A)  indoleacetic acid 
B)  cytokinin 
C)  gibberellin 
D)  abscisic acid 
E)  ethylene 
A)  indoleacetic acid 
B)  cytokinin 
C)  gibberellin 
D)  abscisic acid 
E)  ethylene

Question 20

When an arborist prunes a limb off a valuable tree, he or she usually paints the cut surface. The primary purpose of the paint is to

Accepted Answer

A)  minimize water loss by evaporation from the cut surface. 
B)  improve the appearance of the cut surface. 
C)  stimulate growth of the cork cambium to "heal" the wound. 
D)  block entry of pathogens through the wound. 
E)  induce the production of phytoalexins. 
A)  minimize water loss by evaporation from the cut surface. 
B)  improve the appearance of the cut surface. 
C)  stimulate growth of the cork cambium to "heal" the wound. 
D)  block entry of pathogens through the wound. 
E)  induce the production of phytoalexins.

Exam 39: Plant Responses to Internal and External Signals

What would happen if the secondary messenger cGMP was blocked in the de-etiolation pathway?

Vines in tropical rain forests must grow toward large trees before being able to grow toward the sun. To reach a large tree, the most useful kind of growth movement for a tropical vine presumably would be the opposite of

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

Which of the following hormones would never be found in high concentrations in a dormant overwintering flower bud?

Charles and Francis Darwin concluded from their experiments on phototropism by grass seedlings that the part of the seedling that detects the direction of light is the

The hormone that helps plants respond to drought is

The initial response of the root cells of a tomato plant watered with seawater would be to

Experiments on the positive phototropic response of plants indicate that

Most plants close their stomata at night. What color of light would be most effective in promoting stomatal opening in the middle of the night?

Many plants flower in response to day-length cues. Which of the following statements best summarizes this phenomenon?

Auxin triggers the acidification of cell walls, which results in rapid growth, but also stimulates sustained, long-term cell elongation. What best explains how auxin brings about this dual growth response?

The plant hormone involved in aging and ripening of fruit is

A long-day plant will flower

The transduction pathway that activates systemic acquired resistance in plants is initially signaled by

Why are lateral buds often inhibited from sprouting even though a stem may be actively elongating?

Seed packets give a recommended planting depth for the enclosed seeds. The most likely reason some seeds are to be covered with only ¼ inch of soil is that the

How does indoleacetic acid affect fruit development?

A short-day plant will flower only when

The synthesis of which of the following hormones would be a logical first choice in an attempt to produce normal growth in mutant dwarf plants?

When an arborist prunes a limb off a valuable tree, he or she usually paints the cut surface. The primary purpose of the paint is to

Introduction: Themes in the Study of Life

The Chemical Context of Life

Water and Life

Carbon and the Molecular Diversity of Life

The Structure and Function of Large Biological Molecules

A Tour of the Cell

Membrane Structure and Function

An Introduction to Metabolism

Cellular Respiration and Fermentation

Photosynthesis

Cell Communication

The Cell Cycle

Meiosis and Sexual Life Cycles

Mendel and the Gene Idea

The Chromosomal Basis of Inheritance

The Molecular Basis of Inheritance

From Gene to Protein

Regulation of Gene Expression

Viruses

Biotechnology

Genomes and Their Evolution

Descent with Modification: A Darwinian View of Life

The Evolution of Populations

The Origin of Species

The History of Life on Earth

Phylogeny and the Tree of Life

Bacteria and Archaea

Protists

Plant Diversity I: How Plants Colonized Land

Plant Diversity II: The Evolution of Seed Plants

Fungi

An Overview of Animal Diversity

An Introduction to Invertebrates

The Origin and Evolution of Vertebrates

Plant Structure, Growth, and Development

Resource Acquisition and Transport in Vascular Plants

Soil and Plant Nutrition

Angiosperm Reproduction and Biotechnology

Basic Principles of Animal Form and Function

Animal Nutrition

Circulation and Gas Exchange

The Immune System

Osmoregulation and Excretion

Hormones and the Endocrine System

Animal Reproduction

Animal Development

Neurons, Synapses, and Signaling

Nervous Systems

Sensory and Motor Mechanisms

Animal Behavior

An Introduction to Ecology and the Biosphere

Population Ecology

Community Ecology

Ecosystems and Restoration Ecology

Conservation Biology and Global Change

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