Question 1

Plants are affected by an array of pathogens. Which of the following is a likely plant defence/response against disease?

Accepted Answer

A) cells near the point of infection destroying themselves to prevent the spread of the infection 
B) production of chemicals that repel pathogens 
C) transcriptional level recognition followed by production of stress proteins 
D) thickening the cuticle so that pathogens have trouble penetrating the tissues 
E) stopping all xylem and phloem movement within infected tissues 
A) cells near the point of infection destroying themselves to prevent the spread of the infection 
B) production of chemicals that repel pathogens 
C) transcriptional level recognition followed by production of stress proteins 
D) thickening the cuticle so that pathogens have trouble penetrating the tissues 
E) stopping all xylem and phloem movement within infected tissues

Question 2

Plant hormones produce their effects by

Accepted Answer

A) altering the expression of genes. 
B) modifying the permeability of the plasma membrane. 
C) modifying the structure of the nuclear envelope membrane. 
D) altering the expression of genes and modifying the permeability of the plasma membrane. 
E) modifying the permeability of the plasma membrane and modifying the structure of the nuclear envelope membrane. 
A) altering the expression of genes. 
B) modifying the permeability of the plasma membrane. 
C) modifying the structure of the nuclear envelope membrane. 
D) altering the expression of genes and modifying the permeability of the plasma membrane. 
E) modifying the permeability of the plasma membrane and modifying the structure of the nuclear envelope membrane.

Question 3

Plants that have their flowering inhibited by being exposed to bright lights at night are

Accepted Answer

A) day-neutral plants. 
B) short-night plants. 
C) devoid of phytochrome. 
D) short-day plants. 
E) long-day plants. 
A) day-neutral plants. 
B) short-night plants. 
C) devoid of phytochrome. 
D) short-day plants. 
E) long-day plants.

Question 4

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 5

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) alter the amount of energy available to the plant. 
C) are modified by soil temperature changes. 
D) can reset the biological clock. 
E) are correlated with moisture availability. 
A) are more predictable than air temperature changes. 
B) alter the amount of energy available to the plant. 
C) are modified by soil temperature changes. 
D) can reset the biological clock. 
E) are correlated with moisture availability.

Question 6

All of the following may function in signal transduction in plants except

Accepted Answer

A) calcium ions. 
B) nonrandom mutations. 
C) receptor proteins. 
D) phytochrome. 
E) secondary messengers. 
A) calcium ions. 
B) nonrandom mutations. 
C) receptor proteins. 
D) phytochrome. 
E) secondary messengers.

Question 7

Which of the following statements best summarizes the acid growth hypothesis in an actively growing shoot?

Accepted Answer

A) Auxin stimulates proton pumps in the plasma membrane and tonoplast. 
B) Auxin-activated proton pumps lower the pH of the cell wall, which breaks bonds and makes the walls more flexible. 
C) Auxins and gibberellins together act as a lubricant to help stretch cellulose microfibrils. 
D) Auxins activate aquaporins that increase turgor pressure in the cells. 
E) Auxins and gibberellins are transported to the vacuoles to build up turgor pressure. 
A) Auxin stimulates proton pumps in the plasma membrane and tonoplast. 
B) Auxin-activated proton pumps lower the pH of the cell wall, which breaks bonds and makes the walls more flexible. 
C) Auxins and gibberellins together act as a lubricant to help stretch cellulose microfibrils. 
D) Auxins activate aquaporins that increase turgor pressure in the cells. 
E) Auxins and gibberellins are transported to the vacuoles to build up turgor pressure.

Question 8

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 9

Which of the following watering regimens will be most effective at keeping a lawn green during the hot, dry summer months?

Accepted Answer

A) daily sprinkling to soak the soil to 0.5 inch 
B) sprinkling every other day to soak the soil to 1.0 inch 
C) sprinkling every third day to soak the soil to 2.0 inches 
D) daily sprinkling to soak the soil to 0.5 inch or sprinkling every other day to soak the soil to 1.0 inch 
E) sprinkling every other day to soak the soil to 1.0 inch or sprinkling every third day to soak the soil to 2.0 inches 
A) daily sprinkling to soak the soil to 0.5 inch 
B) sprinkling every other day to soak the soil to 1.0 inch 
C) sprinkling every third day to soak the soil to 2.0 inches 
D) daily sprinkling to soak the soil to 0.5 inch or sprinkling every other day to soak the soil to 1.0 inch 
E) sprinkling every other day to soak the soil to 1.0 inch or sprinkling every third day to soak the soil to 2.0 inches

Question 10

The initial response of the root cells of a tomato plant watered with sea water 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 11

Bald cypress and loblolly pine are both gymnosperm trees native to the southern United States. The cypress grows in swamps; the pine grows in sandy soil. How do you think their anatomies differ?

Accepted Answer

A) There are larger intercellular spaces in the roots of the cypress than in the roots of the pine. 
B) Water-conducting cells are larger in the stems of the cypress than in the stems of the pine. 
C) The springwood and summerwood are more distinct in the cypress. 
D) There is less parenchyma in the roots of the cypress than in the pine roots. 
E) There are no major anatomical differences between these species because they are both gymnosperms. 
A) There are larger intercellular spaces in the roots of the cypress than in the roots of the pine. 
B) Water-conducting cells are larger in the stems of the cypress than in the stems of the pine. 
C) The springwood and summerwood are more distinct in the cypress. 
D) There is less parenchyma in the roots of the cypress than in the pine roots. 
E) There are no major anatomical differences between these species because they are both gymnosperms.

Question 12

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 13

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.

Question 14

Which of the following best describes positive gravitropism exhibited by plant roots?

Accepted Answer

A) It is mediated by auxin similar to the phototropism responses in shoots. 
B) It depends on an inhibition of elongation of some cells. 
C) Gravity causes gibberellins to accumulate on the lower side of roots. 
D) The phenomenon depends upon inhibition of cell elongation of certain root cells by abscisic acid. 
E) All of the above are correct. 
A) It is mediated by auxin similar to the phototropism responses in shoots. 
B) It depends on an inhibition of elongation of some cells. 
C) Gravity causes gibberellins to accumulate on the lower side of roots. 
D) The phenomenon depends upon inhibition of cell elongation of certain root cells by abscisic acid. 
E) All of the above are correct.

Question 15

Both red and blue light are involved in

Accepted Answer

A) stem elongation. 
B) photoperiodism. 
C) positive phototropism. 
D) tracking seasons. 
E) all of the above. 
A) stem elongation. 
B) photoperiodism. 
C) positive phototropism. 
D) tracking seasons. 
E) all of the above.

Question 16

When growing plants in culture, IAA is used to stimulate cell enlargement. Which plant growth regulator has to now be added to stimulate cell division?

Accepted Answer

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

Question 17

Classic experiments suggested that a floral stimulus, florigen, could move across a graft from an induced plant to a noninduced plant and trigger flowering. Recent evidence using Arabidopsis has recently shown that florigen is probably

Accepted Answer

A) a phytochrome molecule that is activated by red light. 
B) a protein that is synthesized in leaves, travels to the shoot apical meristems, and initiates flowering. 
C) a membrane signal that travels through the symplast from leaves to buds. 
D) a second messenger that induces Ca⁺⁺ ions to change membrane potential. 
E) a transcription factor that controls the activation of florigen-specific genes. 
A) a phytochrome molecule that is activated by red light. 
B) a protein that is synthesized in leaves, travels to the shoot apical meristems, and initiates flowering. 
C) a membrane signal that travels through the symplast from leaves to buds. 
D) a second messenger that induces Ca⁺⁺ ions to change membrane potential. 
E) a transcription factor that controls the activation of florigen-specific genes.

Question 18

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 19

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 20

If protein synthesis was blocked in etiolated cells, what would be necessary for the "greening" of these cells?

Accepted Answer

A) reception of light by phytochrome 
B) activation of protein kinase 1 by cAMP 
C) activation of protein kinase 2 by Ca²⁺ 
D) post-translational modification of existing proteins 
E) 100-fold decrease in cytosolic Ca²⁺ levels 
A) reception of light by phytochrome 
B) activation of protein kinase 1 by cAMP 
C) activation of protein kinase 2 by Ca²⁺ 
D) post-translational modification of existing proteins 
E) 100-fold decrease in cytosolic Ca²⁺ levels

Exam 39: Plant Responses to Internal and External Signals

Plants are affected by an array of pathogens. Which of the following is a likely plant defence/response against disease?

Plant hormones produce their effects by

Plants that have their flowering inhibited by being exposed to bright lights at night are

A plant will recognize a pathogenic invader

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

All of the following may function in signal transduction in plants except

Which of the following statements best summarizes the acid growth hypothesis in an actively growing shoot?

Plant hormonal control differs from animal hormonal control in that

Which of the following watering regimens will be most effective at keeping a lawn green during the hot, dry summer months?

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

Bald cypress and loblolly pine are both gymnosperm trees native to the southern United States. The cypress grows in swamps; the pine grows in sandy soil. How do you think their anatomies differ?

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

Which of the following best describes positive gravitropism exhibited by plant roots?

Both red and blue light are involved in

When growing plants in culture, IAA is used to stimulate cell enlargement. Which plant growth regulator has to now be added to stimulate cell division?

Classic experiments suggested that a floral stimulus, florigen, could move across a graft from an induced plant to a noninduced plant and trigger flowering. Recent evidence using Arabidopsis has recently shown that florigen is probably

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

Oat seedlings are sometimes used to study auxins because

If protein synthesis was blocked in etiolated cells, what would be necessary for the "greening" of these cells?

Introduction: Evolution and Themes of Biology

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

Dna Tools and 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 Signalling

Nervous Systems

Sensory and Motor Mechanisms

Animal Behaviour

An Introduction to Ecology and the Biosphere

Population Ecology

Community Ecology

Ecosystems and Restoration Ecology

Conservation Biology and Global Change

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