Question 1

-The figure above shows the cross section of a root grown under different conditions.Explain what is happening in picture B?

Accepted Answer

A) With no oxygen, the root has died. 
B) The root is infested with parasites that are eating the root. 
C) Root cells produce absicic acid to increase tolerance to low oxygen. 
D) Root cells produce cytokinins to promote movement of nutrients to roots. 
E) Low oxygen stimulates production of ethylene which causes apoptosis in some cells of the root cortex. 
A) With no oxygen, the root has died. 
B) The root is infested with parasites that are eating the root. 
C) Root cells produce absicic acid to increase tolerance to low oxygen. 
D) Root cells produce cytokinins to promote movement of nutrients to roots. 
E) Low oxygen stimulates production of ethylene which causes apoptosis in some cells of the root cortex.

Question 2

A flash of red light followed by a flash of far-red light given during the middle of the night to a short-day plant will likely

Accepted Answer

A) cause increased flower production. 
B) have no effect upon flowering. 
C) inhibit flowering. 
D) stimulate flowering. 
E) convert florigen to the active form. 
A) cause increased flower production. 
B) have no effect upon flowering. 
C) inhibit flowering. 
D) stimulate flowering. 
E) convert florigen to the active form.

Question 3

Which of the following best explains both the growth of a vine up the trunk of a tree as well as the directional growth of a houseplant toward a window?

Accepted Answer

A) nastic movement 
B) taxic movement 
C) tropism response 
D) morphological response 
E) acclimation 
A) nastic movement 
B) taxic movement 
C) tropism response 
D) morphological response 
E) acclimation

Question 4

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 5

If a long-day plant has a critical night length of 9 hours,which 24-hour cycle would prevent flowering?

Accepted Answer

A) 16 hours light/8 hours dark 
B) 14 hours light/10 hours dark 
C) 15.5 hours light/8.5 hours dark 
D) 4 hours light/8 hours dark/4 hours light/8 hours dark 
E) 8 hours light/8 hours dark/light flash/8 hours dark 
A) 16 hours light/8 hours dark 
B) 14 hours light/10 hours dark 
C) 15.5 hours light/8.5 hours dark 
D) 4 hours light/8 hours dark/4 hours light/8 hours dark 
E) 8 hours light/8 hours dark/light flash/8 hours dark

Question 6

The ripening of fruit and the dropping of leaves and fruit are principally controlled by

Accepted Answer

A) auxins. 
B) cytokinins. 
C) indole acetic acid. 
D) ethylene. 
E) carbon dioxide concentration (in air). 
A) auxins. 
B) cytokinins. 
C) indole acetic acid. 
D) ethylene. 
E) carbon dioxide concentration (in air).

Question 7

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 8

External stimuli would be received most quickly by a plant cell if the receptors for signal transduction were located in the

Accepted Answer

A) plasma membrane. 
B) cytoplasmic matrix. 
C) endoplasmic reticulum. 
D) nuclear membrane. 
E) nucleoplasm. 
A) plasma membrane. 
B) cytoplasmic matrix. 
C) endoplasmic reticulum. 
D) nuclear membrane. 
E) nucleoplasm.

Question 9

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 10

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 11

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 12

Who might be interested in using cytokinins?

Accepted Answer

A) grocers, to spray on fruit to enhance ripening in the store 
B) consumers, to spray on fruit before eating to enhance taste 
C) florists, to dip stems in to keep leaves green longer 
D) farmers, to spray on fruit after picking to stall ripening 
A) grocers, to spray on fruit to enhance ripening in the store 
B) consumers, to spray on fruit before eating to enhance taste 
C) florists, to dip stems in to keep leaves green longer 
D) farmers, to spray on fruit after picking to stall ripening

Question 13

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 14

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.

Question 15

-Suppose you laid a seedling on its side so that the root was parallel to the ground as shown in the figure above.Several hours after the change in position,where in the root cells (position A,B,or C in the figure above)would you find the amyloplasts?

Accepted Answer

A) A 
B) B 
C) C 
A) A 
B) B 
C) C

Question 16

Plant hormones

Accepted Answer

A) in plant cells naturally exist in very large amounts. 
B) change their shape in response to stimulus. 
C) are unable to move from one cell to another. 
D) affect only cells with the appropriate receptor. 
A) in plant cells naturally exist in very large amounts. 
B) change their shape in response to stimulus. 
C) are unable to move from one cell to another. 
D) affect only cells with the appropriate receptor.

Question 17

A short-day plant exposed to nights longer than the minimum for flowering but interrupted by short flashes of light

Accepted Answer

A) never flower. 
B) might flower depending upon the duration of the light flash. 
C) will not be affected and will flower. 
D) might flower depending upon the wavelengths of the light flashes. 
E) will still flower if ethylene is administered. 
A) never flower. 
B) might flower depending upon the duration of the light flash. 
C) will not be affected and will flower. 
D) might flower depending upon the wavelengths of the light flashes. 
E) will still flower if ethylene is administered.

Exam 39: Plant Responses to Internal and External Signals

-The figure above shows the cross section of a root grown under different conditions.Explain what is happening in picture B?

A flash of red light followed by a flash of far-red light given during the middle of the night to a short-day plant will likely

Which of the following best explains both the growth of a vine up the trunk of a tree as well as the directional growth of a houseplant toward a window?

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

If a long-day plant has a critical night length of 9 hours,which 24-hour cycle would prevent flowering?

The ripening of fruit and the dropping of leaves and fruit are principally controlled by

External stimuli would be received most quickly by a plant cell if the receptors for signal transduction were located in the

Plant hormonal control differs from animal hormonal control in that

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?

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

Who might be interested in using cytokinins?

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

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

-Suppose you laid a seedling on its side so that the root was parallel to the ground as shown in the figure above.Several hours after the change in position,where in the root cells (position A,B,or C in the figure above)would you find the amyloplasts?

Plant hormones

A short-day plant exposed to nights longer than the minimum for flowering but interrupted by short flashes of light

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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