Question 1

Which of the following treatments would enhance the level of the Pfr form of phytochrome?

Accepted Answer

A)  exposure to far-red light 
B)  exposure to red light 
C)  long dark period 
D)  inhibition of protein synthesis 
E)  synthesis of phosphorylating enzymes 
A)  exposure to far-red light 
B)  exposure to red light 
C)  long dark period 
D)  inhibition of protein synthesis 
E)  synthesis of phosphorylating enzymes

Question 2

A plant will recognize a pathogenic invader

Accepted Answer

A)  if it has many specific plant disease resistance (R) genes. 
B)  when the pathogen has an R gene complementary to the plant's antivirulence (Avr) gene. 
C)  only if the pathogen and the plant have the same R genes. 
D)  if it has the specific R gene that corresponds to the pathogen molecule encoded by an Avr gene. 
E)  when the pathogen secretes Avr protein. 
A)  if it has many specific plant disease resistance (R) genes. 
B)  when the pathogen has an R gene complementary to the plant's antivirulence (Avr) gene. 
C)  only if the pathogen and the plant have the same R genes. 
D)  if it has the specific R gene that corresponds to the pathogen molecule encoded by an Avr gene. 
E)  when the pathogen secretes Avr protein.

Question 3

Which of the following statements is correct with regards to a "circadian rhythm" in plants?

Accepted Answer

A)  It may have the same signal transduction pathway in all organisms. 
B)  Once set, it cannot be changed. 
C)  It works independently of photoperiodic responses. 
D)  Once set, it is independent of external signals. 
E)  It can be changed to a longer or shorter period by altering the light quality. 
A)  It may have the same signal transduction pathway in all organisms. 
B)  Once set, it cannot be changed. 
C)  It works independently of photoperiodic responses. 
D)  Once set, it is independent of external signals. 
E)  It can be changed to a longer or shorter period by altering the light quality.

Question 4

You are part of a desert plant research team trying to discover crops that will be productive in arid climates. You discover a plant that produces a hormone under water-deficit conditions that triggers a suite of drought responses. Most likely the hormone is

Accepted Answer

A)  ABA. 
B)  GA. 
C)  IAA. 
D)  2, 4-D. 
E)  salicylic acid. 
A)  ABA. 
B)  GA. 
C)  IAA. 
D)  2, 4-D. 
E)  salicylic acid.

Question 5

If a short-day plant has a critical night length of 15 hours, then which of the following 24-hour cycles will prevent flowering?

Accepted Answer

A)  8 hours light/16 hours dark 
B)  4 hours light/20 hours dark 
C)  6 hours light/2 hours dark/light flash/16 hours dark 
D)  8 hours light/8 hours dark/light flash/8 hours dark 
E)  2 hours light/20 hours dark/2 hours light 
A)  8 hours light/16 hours dark 
B)  4 hours light/20 hours dark 
C)  6 hours light/2 hours dark/light flash/16 hours dark 
D)  8 hours light/8 hours dark/light flash/8 hours dark 
E)  2 hours light/20 hours dark/2 hours light

Question 6

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 plants 
E)  all of the above 
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 plants 
E)  all of the above

Question 7

Plant hormones can have different effects at different concentrations. This explains how

Accepted Answer

A)  some plants are long-day plants and others are short-day plants. 
B)  signal transduction pathways in plants are different from those in animals. 
C)  plant genes recognize pathogen genes. 
D)  auxin can stimulate cell elongation in apical meristems, yet will inhibit the growth of axillary buds. 
E)  gibberellin concentration can both induce and break dormancy. 
A)  some plants are long-day plants and others are short-day plants. 
B)  signal transduction pathways in plants are different from those in animals. 
C)  plant genes recognize pathogen genes. 
D)  auxin can stimulate cell elongation in apical meristems, yet will inhibit the growth of axillary buds. 
E)  gibberellin concentration can both induce and break dormancy.

Question 8

Oat seedlings are sometimes used to study auxins because

Accepted Answer

A)  they are a readily accessible monocot, and auxins affect only monocots. 
B)  they have a stiff coleoptile. 
C)  they green rapidly in the light. 
D)  their coleoptile exhibits a strong positive phototropism. 
E)  monocots inactivate synthetic auxins. 
A)  they are a readily accessible monocot, and auxins affect only monocots. 
B)  they have a stiff coleoptile. 
C)  they green rapidly in the light. 
D)  their coleoptile exhibits a strong positive phototropism. 
E)  monocots inactivate synthetic auxins.

Question 9

Which of the following plant growth responses is primarily due to the action of auxins?

Accepted Answer

A)  leaf abscission 
B)  fruit development 
C)  cell division 
D)  the detection of photoperiod 
E)  cell elongation 
A)  leaf abscission 
B)  fruit development 
C)  cell division 
D)  the detection of photoperiod 
E)  cell elongation

Question 10

Which of the following plant hormones are most likely to act synergistically if expressed or applied to a drought-stricken plant?

Accepted Answer

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

Question 11

Which of the following is currently the most powerful method of research on plant hormones?

Accepted Answer

A)  comparing photoperiodic responses 
B)  comparing tropisms with turgor movements 
C)  subjecting plants to various abiotic stresses 
D)  studying plant/animal interactions 
E)  analyzing mutant plants 
A)  comparing photoperiodic responses 
B)  comparing tropisms with turgor movements 
C)  subjecting plants to various abiotic stresses 
D)  studying plant/animal interactions 
E)  analyzing mutant plants

Question 12

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

Accepted Answer

A)  rapid growth response. 
B)  potassium channels. 
C)  nervous tissue. 
D)  aquaporins. 
E)  stress proteins. 
A)  rapid growth response. 
B)  potassium channels. 
C)  nervous tissue. 
D)  aquaporins. 
E)  stress proteins.

Question 13

In cases where plants exhibit generalized defense responses in organs distant from the infection site, this is termed

Accepted Answer

A)  hyperactive responses. 
B)  systemic acquired resistance. 
C)  pleiotropy. 
D)  hyperplasia. 
E)  general systemic response. 
A)  hyperactive responses. 
B)  systemic acquired resistance. 
C)  pleiotropy. 
D)  hyperplasia. 
E)  general systemic response.

Question 14

Figure 39.1
-The heavy line in Figure 39.1 illustrates the relationship between auxin concentration and cell growth
In stem tissues. If the same range of concentrations were applied to lateral buds, what curve(s)would probably be produced?

Accepted Answer

A)  I 
B)  II 
C)  III 
D)  II or III 
E)  I or III 
A)  I 
B)  II 
C)  III 
D)  II or III 
E)  I or III

Question 15

Plant hormonal control differs from animal hormonal control in that

Accepted Answer

A)  there are no separate 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)  plants do not exhibit feedback mechanisms like animals. 
D)  only animal hormone concentrations are developmentally regulated. 
E)  only animal hormones may have either external or internal receptors. 
A)  there are no separate 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)  plants do not exhibit feedback mechanisms like animals. 
D)  only animal hormone concentrations are developmentally regulated. 
E)  only animal hormones may have either external or internal receptors.

Question 16

Which of the following would only be activated or upregulated after a plant has already been infected by a pathogen?

Accepted Answer

A)  phytochrome 
B)  salicylic acid 
C)  molecular chaperones 
D)  stress proteins 
E)  brassinosteroids 
A)  phytochrome 
B)  salicylic acid 
C)  molecular chaperones 
D)  stress proteins 
E)  brassinosteroids

Question 17

If the range of a species of plants expands to a higher latitude, which of the following processes is the most likely to be modified by natural selection?

Accepted Answer

A)  circadian rhythm 
B)  photoperiodic response 
C)  phototropic response 
D)  biological clock 
E)  thigmomorphogenesis 
A)  circadian rhythm 
B)  photoperiodic response 
C)  phototropic response 
D)  biological clock 
E)  thigmomorphogenesis

Question 18

A botanist exposed two groups of the same plant species to two photoperiods-one with 14 hours of light and 10 hours of dark and the other with 10 hours of light and 14 hours of dark. Under the first set of conditions, the plants flowered, but they failed to flower under the second set of conditions. Which of the following conclusions would be consistent with these results?

Accepted Answer

A)  The critical night length is 14 hours. 
B)  The plants are short-day plants. 
C)  The critical day length is 10 hours. 
D)  The plants can convert phytochrome to florigen. 
E)  The plants flower in the late spring. 
A)  The critical night length is 14 hours. 
B)  The plants are short-day plants. 
C)  The critical day length is 10 hours. 
D)  The plants can convert phytochrome to florigen. 
E)  The plants flower in the late spring.

Question 19

Which of the following conclusions is supported by the research of both Went and Charles and Francis Darwin on shoot responses to light?

Accepted Answer

A)  When shoots are exposed to light, a chemical substance migrates toward the light. 
B)  Agar contains a chemical substance that mimics a plant hormone. 
C)  A chemical substance involved in shoot bending is produced in shoot tips. 
D)  Once shoot tips have been cut, normal growth cannot be induced. 
E)  Light stimulates the synthesis of a plant hormone that responds to light. 
A)  When shoots are exposed to light, a chemical substance migrates toward the light. 
B)  Agar contains a chemical substance that mimics a plant hormone. 
C)  A chemical substance involved in shoot bending is produced in shoot tips. 
D)  Once shoot tips have been cut, normal growth cannot be induced. 
E)  Light stimulates the synthesis of a plant hormone that responds to light.

Question 20

In nature, poinsettias bloom in early March. Research has shown that the flowering process is triggered three months before blooming occurs. In order to make poinsettias bloom in December, florists change the length of the light-dark cycle in September. Given the information and clues above, which of the following is a correct statement about poinsettias?

Accepted Answer

A)  They are short-day plants. 
B)  They require a light period longer than some set minimum. 
C)  They require a shorter dark period than is available in September. 
D)  The dark period can be interrupted without affecting flowering. 
E)  They will flower even if there are brief periods of far-red illumination during the nighttime. 
A)  They are short-day plants. 
B)  They require a light period longer than some set minimum. 
C)  They require a shorter dark period than is available in September. 
D)  The dark period can be interrupted without affecting flowering. 
E)  They will flower even if there are brief periods of far-red illumination during the nighttime.

Exam 39: Plant Responses to Internal and External Signals

Which of the following treatments would enhance the level of the Pfr form of phytochrome?

A plant will recognize a pathogenic invader

Which of the following statements is correct with regards to a "circadian rhythm" in plants?

You are part of a desert plant research team trying to discover crops that will be productive in arid climates. You discover a plant that produces a hormone under water-deficit conditions that triggers a suite of drought responses. Most likely the hormone is

If a short-day plant has a critical night length of 15 hours, then which of the following 24-hour cycles will prevent flowering?

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?

Plant hormones can have different effects at different concentrations. This explains how

Oat seedlings are sometimes used to study auxins because

Which of the following plant growth responses is primarily due to the action of auxins?

Which of the following plant hormones are most likely to act synergistically if expressed or applied to a drought-stricken plant?

Which of the following is currently the most powerful method of research on plant hormones?

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

In cases where plants exhibit generalized defense responses in organs distant from the infection site, this is termed

Figure 39.1 -The heavy line in Figure 39.1 illustrates the relationship between auxin concentration and cell growth In stem tissues. If the same range of concentrations were applied to lateral buds, what curve(s)would probably be produced?

Plant hormonal control differs from animal hormonal control in that

Which of the following would only be activated or upregulated after a plant has already been infected by a pathogen?

If the range of a species of plants expands to a higher latitude, which of the following processes is the most likely to be modified by natural selection?

Which of the following conclusions is supported by the research of both Went and Charles and Francis Darwin on shoot responses to light?

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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