Question 1

The biological clock controlling circadian rhythms must ultimately

Accepted Answer

A)  depend on environmental cues. 
B)  affect gene transcription. 
C)  stabilize on a 24-hour cycle. 
D)  speed up or slow down with increasing or decreasing temperature. 
A)  depend on environmental cues. 
B)  affect gene transcription. 
C)  stabilize on a 24-hour cycle. 
D)  speed up or slow down with increasing or decreasing temperature.

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. 
A)  cause increased flower production. 
B)  have no effect upon flowering. 
C)  inhibit flowering. 
D)  stimulate flowering.

Question 3

A plant seedling bends toward sunlight because

Accepted Answer

A)  auxin migrates to the lower part of the stem due to gravity. 
B)  there is more auxin on the light side of the stem. 
C)  auxin is destroyed more quickly on the dark side of the stem. 
D)  auxin is found in greatest abundance on the dark side of the stem. 
A)  auxin migrates to the lower part of the stem due to gravity. 
B)  there is more auxin on the light side of the stem. 
C)  auxin is destroyed more quickly on the dark side of the stem. 
D)  auxin is found in greatest abundance on the dark side of the stem.

Question 4

Most scientists agree that global warming is under way; 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 to improve plant response to and survival of 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 
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

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 
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

Question 6

Which part of plant structure synthesizes cytokinins primarily?

Accepted Answer

A)  shoot apical meristem 
B)  roots 
C)  ripened fruits 
D)  almost all plant parts 
A)  shoot apical meristem 
B)  roots 
C)  ripened fruits 
D)  almost all plant parts

Question 7

Which of the following statements applies to plant growth regulators?

Accepted Answer

A)  They only act by altering gene expression. 
B)  They often have a multiplicity of effects. 
C)  They function independently of other hormones. 
D)  They affect the division and elongation, but not the differentiation, of cells. 
A)  They only act by altering gene expression. 
B)  They often have a multiplicity of effects. 
C)  They function independently of other hormones. 
D)  They affect the division and elongation, but not the differentiation, of cells.

Question 8

Which of the following conclusions is supported by the research of both Frits 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. 
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.

Question 9

According to the acid growth hypothesis, auxin works by

Accepted Answer

A)  dissolving sieve plates, permitting more rapid transport of nutrients. 
B)  dissolving the cell membranes temporarily, permitting cells that were on the verge of dividing to divide more rapidly. 
C)  changing the pH within the cell, which would permit the electron transport chain to operate more efficiently. 
D)  increasing wall plasticity and allowing the affected cell walls to elongate. 
A)  dissolving sieve plates, permitting more rapid transport of nutrients. 
B)  dissolving the cell membranes temporarily, permitting cells that were on the verge of dividing to divide more rapidly. 
C)  changing the pH within the cell, which would permit the electron transport chain to operate more efficiently. 
D)  increasing wall plasticity and allowing the affected cell walls to elongate.

Question 10

Almost all plant cells have the ability to produce abscisic acid. One of the functions of abscisic acid in plants is to

Accepted Answer

A)  stimulate cell elongation. 
B)  regulate development of fruit. 
C)  promote stomatal closure during drought stress. 
D)  delay leaf senescence. 
A)  stimulate cell elongation. 
B)  regulate development of fruit. 
C)  promote stomatal closure during drought stress. 
D)  delay leaf senescence.

Question 11

If a farmer wanted more loosely packed clusters of grapes, he would most likely spray the immature bunches with

Accepted Answer

A)  auxin. 
B)  gibberellins. 
C)  cytokinins. 
D)  ethylene. 
A)  auxin. 
B)  gibberellins. 
C)  cytokinins. 
D)  ethylene.

Question 12

In nature, poinsettias bloom in early March. Research has shown that the flowering process is triggered 3 months before blooming occurs. In order to make poinsettias bloom in December, florists change the length of the light/dark cycle in September. Given this information and clues, 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. 
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.

Question 13

What does a short-day plant require in order to flower?

Accepted Answer

A)  a burst of red light in the middle of the night 
B)  a burst of far-red light in the middle of the night 
C)  a day that is longer than a certain length 
D)  a night that is longer than a certain length 
A)  a burst of red light in the middle of the night 
B)  a burst of far-red light in the middle of the night 
C)  a day that is longer than a certain length 
D)  a night that is longer than a certain length

Question 14

Classic experiments suggested that a floral stimulus, florigen, could move across a graft from an induced plant to a non-induced plant and trigger flowering. Recent evidence using Arabidopsis has 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 Ca2+ to change membrane potential. 
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 Ca2+ to change membrane potential.

Question 15

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

Exam 31: Plant Responses to Internal and External Signals

The biological clock controlling circadian rhythms must ultimately

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

A plant seedling bends toward sunlight because

Most scientists agree that global warming is under way; 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 to improve plant response to and survival of heat stress?

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

Which part of plant structure synthesizes cytokinins primarily?

Which of the following statements applies to plant growth regulators?

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

According to the acid growth hypothesis, auxin works by

Almost all plant cells have the ability to produce abscisic acid. One of the functions of abscisic acid in plants is to

If a farmer wanted more loosely packed clusters of grapes, he would most likely spray the immature bunches with

What does a short-day plant require in order to flower?

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

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

Introduction: Evolution and the Foundations of Biology

The Chemical Context of Life

Carbon and the Molecular Diversity of Life

A Tour of the Cell

Membrane Transport and Cell Signaling

An Introduction to Metabolism

Cellular Respiration and Fermentation

Photosynthesis

The Cell Cycle

Meiosis and Sexual Life Cycles

Mendel and the Gene Idea

The Chromosomal Basis of Inheritance

The Molecular Basis of Inheritance

Gene Expression: From Gene to Protein

Regulation of Gene Expression

Development, Stem Cells, and Cancer

Viruses

Genomes and Their Evolution

Descent With Modification

Phylogeny

The Evolution of Populations

The Origin of Species

Broad Patterns of Evolution

Early Life and the Diversification of Prokaryotes

The Origin and Diversification of Eukaryotes

The Colonization of Land by Plants and Fungi

The Rise of Animal Diversity

Plant Structure and Growth

Resource Acquisition, Nutrition, and Transport in Vascular Plants

Reproduction and Domestication of Flowering Plants

Homeostasis and Endocrine Signaling

Animal Nutrition

Circulation and Gas Exchange

The Immune System

Reproduction and Development

Neurons, Synapses, and Signaling

Nervous and Sensory Systems

Motor Mechanisms and Behavior

Population Ecology and the Distribution of Organisms

Species Interactions

Ecosystems and Energy

Global Ecology and Conservation Biology

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