Question 1

Which of the following options lists the events leading to leaf fall in deciduous trees in the correct order?

Accepted Answer

A) shortening days,increase in ethylene production,formation of abscission layer 
B) shortening days,formation of abscission layer,decrease in ethylene levels 
C) formation of abscission layer,increase in ethylene levels,decrease in auxin levels 
D) decrease in ethylene levels,shortening days,formation of abscission layer 
A) shortening days,increase in ethylene production,formation of abscission layer 
B) shortening days,formation of abscission layer,decrease in ethylene levels 
C) formation of abscission layer,increase in ethylene levels,decrease in auxin levels 
D) decrease in ethylene levels,shortening days,formation of abscission layer A

Question 2

Which of the following is a health benefit associated with increasing the amount of soybeans in the human diet?

Accepted Answer

A) decreased amount of fiber in the diet 
B) removal of antioxidants from the body 
C) decreased LDL levels 
D) decreased HDL levels 
A) decreased amount of fiber in the diet 
B) removal of antioxidants from the body 
C) decreased LDL levels 
D) decreased HDL levels C

Question 3

Which type of plant hormone generally acts as a growth inhibitor?

Accepted Answer

A) cytokinins 
B) abscisic acid 
C) auxins 
D) gibberellins 
A) cytokinins 
B) abscisic acid 
C) auxins 
D) gibberellins B

Question 4

Fruit that forms on an unpollinated plant in response to a hormone will lack

Accepted Answer

A) rind. 
B) seeds. 
C) naturally occurring hormones. 
D) flavor. 
A) rind. 
B) seeds. 
C) naturally occurring hormones. 
D) flavor.

Question 5

Which of the following statements is supported by this figure?

Accepted Answer

A) Auxin concentrations above 0.9 g/L are best for promoting stem elongation. 
B) Auxin concentrations around 10- 4 g/L promote stem elongation but inhibit root elongation. 
C) The greater the concentration of auxin,the more promotion of root elongation occurs. 
D) Auxin concentrations below 10- 8 g/L promote both root and stem elongation. 
A) Auxin concentrations above 0.9 g/L are best for promoting stem elongation. 
B) Auxin concentrations around 10- 4 g/L promote stem elongation but inhibit root elongation. 
C) The greater the concentration of auxin,the more promotion of root elongation occurs. 
D) Auxin concentrations below 10- 8 g/L promote both root and stem elongation.

Question 6

Which of the following processes underlies the thigmotropic behavior of a green bean tendril?

Accepted Answer

A) slower growth on the side where an object is touching the tendril 
B) extra proliferation of cells on the shaded side of the tendril 
C) rotation of the tendril in response to photoperiod 
D) rotation of the tendril in response to a biological clock 
A) slower growth on the side where an object is touching the tendril 
B) extra proliferation of cells on the shaded side of the tendril 
C) rotation of the tendril in response to photoperiod 
D) rotation of the tendril in response to a biological clock

Question 7

What is one main effect of auxins on plant growth?

Accepted Answer

A) They reduce growth by inhibiting cell division. 
B) Auxins have no effect on plant growth. 
C) They increase growth by promoting cell elongation. 
D) They increase growth by increasing the rate of photosynthesis. 
A) They reduce growth by inhibiting cell division. 
B) Auxins have no effect on plant growth. 
C) They increase growth by promoting cell elongation. 
D) They increase growth by increasing the rate of photosynthesis.

Question 8

Under what conditions would you expect a plant to have the highest concentration of abscisic acid?

Accepted Answer

A) in a houseplant growing in low light conditions 
B) in a desert after a long drought 
C) in a wet tropical rain forest 
D) in a cool environment after a heavy rain 
A) in a houseplant growing in low light conditions 
B) in a desert after a long drought 
C) in a wet tropical rain forest 
D) in a cool environment after a heavy rain

Question 9

Which of the following is one adaptive advantage for deciduous plants that lose their leaves during the winter?

Accepted Answer

A) A layer of leaves on the ground helps keep plant roots warm. 
B) Production of new leaves each spring is more efficient than supporting old leaves all winter. 
C) It prevents water loss from leaves when soil water is unavailable due to freezing. 
D) If leaves are damaged by frost,the tree will die. 
A) A layer of leaves on the ground helps keep plant roots warm. 
B) Production of new leaves each spring is more efficient than supporting old leaves all winter. 
C) It prevents water loss from leaves when soil water is unavailable due to freezing. 
D) If leaves are damaged by frost,the tree will die.

Question 10

Which hormone prevents a seed released in the fall from germinating immediately?

Accepted Answer

A) abscisic acid 
B) gibberellins 
C) auxins 
D) ethylene 
A) abscisic acid 
B) gibberellins 
C) auxins 
D) ethylene

Question 11

Mimosa plants spread their leaflets during the day and fold them at night.You decide to design an experiment to test whether Mimosa's leaf movements are controlled by a biological clock.Which of the following experiments would be the best test of your hypothesis?

Accepted Answer

A) Putting the plant in a dark closet at nightfall.Check on the plant in the morning about 10 hours later,while the plant is still in the closet.If the leaves are open,a biological clock is indicated. 
B) Growing the plant indoors and turning the lights on in the middle of the night.If a biological clock is controlling leaf movement,the leaves will open. 
C) Subjecting the plant to a flash of red light in the middle of the night.If the leaves open at the usual time the next morning,a biological clock mechanism is ruled out. 
D) Putting the plant in a dark closet in the middle of the day.If the leaves close,a biological clock mechanism is ruled out. 
A) Putting the plant in a dark closet at nightfall.Check on the plant in the morning about 10 hours later,while the plant is still in the closet.If the leaves are open,a biological clock is indicated. 
B) Growing the plant indoors and turning the lights on in the middle of the night.If a biological clock is controlling leaf movement,the leaves will open. 
C) Subjecting the plant to a flash of red light in the middle of the night.If the leaves open at the usual time the next morning,a biological clock mechanism is ruled out. 
D) Putting the plant in a dark closet in the middle of the day.If the leaves close,a biological clock mechanism is ruled out.

Question 12

The plant growth response to touch is known as

Accepted Answer

A) gravitropism. 
B) thigmotropism. 
C) bolting. 
D) geotropism. 
A) gravitropism. 
B) thigmotropism. 
C) bolting. 
D) geotropism.

Question 13

A plant will only flower if the night length is longer than 14 hours.This plant is a

Accepted Answer

A) short- day plant. 
B) long- day plant. 
C) day- neutral plant. 
D) short- night plant. 
A) short- day plant. 
B) long- day plant. 
C) day- neutral plant. 
D) short- night plant.

Question 14

When a nursery worker pinches off the terminal buds on a young chrysanthemum plant to make it grow bushy,which of the following plant hormones is mainly responsible for growth of side branches?

Accepted Answer

A) a cytokinin 
B) an auxin 
C) a gibberellin 
D) abscisic acid 
A) a cytokinin 
B) an auxin 
C) a gibberellin 
D) abscisic acid

Question 15

What dense storage granules in plant cells are thought to contribute to gravitropism?

Accepted Answer

A) starch 
B) proteins 
C) chlorophyll 
D) cellulose 
A) starch 
B) proteins 
C) chlorophyll 
D) cellulose

Question 16

Which of the following is a way that plants use animals as a defense against herbivores?

Accepted Answer

A) attraction of wasps that kill herbivorous caterpillars 
B) coevolution between plants and predators 
C) production of an amino acid that harms herbivores 
D) release of microbe- killing chemicals in response to infection 
A) attraction of wasps that kill herbivorous caterpillars 
B) coevolution between plants and predators 
C) production of an amino acid that harms herbivores 
D) release of microbe- killing chemicals in response to infection

Question 17

A biologist interested in determining which plant organs (stems,buds,leaves,etc.)are responsible for sensing photoperiod might perform which of the following experiments?

Accepted Answer

A) measure auxin levels in different parts of the plant before and after exposure to light 
B) cover different plant organs with a foil covering to prevent light exposure 
C) expose the plants to different wavelengths of light 
D) remove the apical meristems from different parts of the plant 
A) measure auxin levels in different parts of the plant before and after exposure to light 
B) cover different plant organs with a foil covering to prevent light exposure 
C) expose the plants to different wavelengths of light 
D) remove the apical meristems from different parts of the plant

Question 18

Synthetic auxins are used commercially

Accepted Answer

A) to promote flowering in ornamental crops. 
B) to promote seed germination. 
C) to promote side branching to produce bushier crops. 
D) as a broadleaf weed killer. 
A) to promote flowering in ornamental crops. 
B) to promote seed germination. 
C) to promote side branching to produce bushier crops. 
D) as a broadleaf weed killer.

Question 19

One of the experiments in phototropism involved cutting off the tips of grass seedlings before exposing them to light from one side.The decapitated seedlings did not bend toward light.A valid conclusion from this experiment would be that

Accepted Answer

A) light is perceived by the tip of grass plants. 
B) plants cannot engage in photosynthesis without the tip of the plant. 
C) hormones are produced in all parts of the plant. 
D) a foil cover over the tip of the seedlings would cause them to bend. 
A) light is perceived by the tip of grass plants. 
B) plants cannot engage in photosynthesis without the tip of the plant. 
C) hormones are produced in all parts of the plant. 
D) a foil cover over the tip of the seedlings would cause them to bend.

Question 20

Christmas cactus is a short- day plant that usually blooms in the winter.Which of the following strategies might induce it to bloom for the 4th of July?

Accepted Answer

A) putting it in a cool,well- lighted place from time to time during June 
B) leaving it in a dark closet all night and part of each morning during June 
C) exposing it to light several times during each night in June 
D) putting it in a dark closet for a short time every afternoon during June 
A) putting it in a cool,well- lighted place from time to time during June 
B) leaving it in a dark closet all night and part of each morning during June 
C) exposing it to light several times during each night in June 
D) putting it in a dark closet for a short time every afternoon during June

Exam 33: Control Systems in Plants

Which of the following options lists the events leading to leaf fall in deciduous trees in the correct order?

Which of the following is a health benefit associated with increasing the amount of soybeans in the human diet?

Which type of plant hormone generally acts as a growth inhibitor?

Fruit that forms on an unpollinated plant in response to a hormone will lack

Which of the following statements is supported by this figure?

Which of the following processes underlies the thigmotropic behavior of a green bean tendril?

What is one main effect of auxins on plant growth?

Under what conditions would you expect a plant to have the highest concentration of abscisic acid?

Which of the following is one adaptive advantage for deciduous plants that lose their leaves during the winter?

Which hormone prevents a seed released in the fall from germinating immediately?

Mimosa plants spread their leaflets during the day and fold them at night.You decide to design an experiment to test whether Mimosa's leaf movements are controlled by a biological clock.Which of the following experiments would be the best test of your hypothesis?

The plant growth response to touch is known as

A plant will only flower if the night length is longer than 14 hours.This plant is a

When a nursery worker pinches off the terminal buds on a young chrysanthemum plant to make it grow bushy,which of the following plant hormones is mainly responsible for growth of side branches?

What dense storage granules in plant cells are thought to contribute to gravitropism?

Which of the following is a way that plants use animals as a defense against herbivores?

A biologist interested in determining which plant organs (stems,buds,leaves,etc.)are responsible for sensing photoperiod might perform which of the following experiments?

Synthetic auxins are used commercially

One of the experiments in phototropism involved cutting off the tips of grass seedlings before exposing them to light from one side.The decapitated seedlings did not bend toward light.A valid conclusion from this experiment would be that

Christmas cactus is a short- day plant that usually blooms in the winter.Which of the following strategies might induce it to bloom for the 4th of July?

Biology: Exploring Life

The Chemical Basis of Life

The Molecules of Cells

A Tour of the Cell

The Working Cell

How Cells Harvest Chemical Energy

Photosynthesis: Using Light to Make Food

The Cellular Basis of Reproduction and Inheritance

Patterns of Inheritance

Molecular Biology of the Gene

How Genes Are Controlled

Dna Technology and Genomics

How Populations Evolve

The Origin of Species

Tracing Evolutionary History

Microbial Life: Prokaryotes and Protists

The Evolution of Plant and Fungal Diversity

The Evolution of Invertebrate Diversity

The Evolution of Vertebrate Diversity

Unifying Concepts of Animal Structure and Function

Nutrition and Digestion

Gas Exchange

Circulation

The Immune System

Control of Body Temperature and Water Balance

Hormones and the Endocrine System

Reproduction and Embryonic Development

Nervous Systems

The Senses

How Animals Move

Plant Structure,growth,and Reproduction

Plant Nutrition and Transport

The Biosphere: an Introduction to Earths Diverse Environments

Behavioral Adaptations to the Environment

Population Ecology

Communities and Ecosystems

Conservation Biology

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