Question 1

Some plants are able to endure frequent flooding events because they form

Accepted Answer

A)   more xylem.
B)   an extra layer of spongy mesophyll.
C)   adventitious roots that reach above the surface of the water.
D)   an extra porpous epidermal tissue.E) A) and B)
F) B) and D) C

Question 2

Halophytes are plants that live in saline soils. The high osmotic potential of the salt solution in the soil creates a very negative water potential. What can halophytes do so that water will flow into the roots?

Accepted Answer

A)   They can close their stomata so that less water is lost through transpiration.
B)   They can open all their stomata so that transpiration "pulls" more water into the roots.
C)   They can increase the solute concentration in their roots creating a water potential that is more negative than the soil.
D)   They can pump ions out of the plant creating a water potential in the roots that is more positive than the soil.
E)   They can remove the mycorrhizal fungi from their roots decreasing the competition for water.F) D) and E)
G) A) and B) C

Question 3

Several scientists, including Charles and Francis Darwin, Frits Went and others, demonstrated that auxins caused stems to bend toward light in a series of elaborate experiments. Went was the researcher who finally determined that bending of the stem toward light was a result of which mechanism?

Accepted Answer

A)   Light caused a reduction in auxin concentration and a reduction in stem elongation on the lighted side of the plant stem, and thus a bending in the direction of the light.
B)   The transport of auxin to the shaded side of the plant stem stimulated stem elongation and a bending in the direction of the light.
C)   Auxin concentration was equal on both sides (lighted and shaded)  of the stem; however, the apical meristem responded to the presence of light.
D)   A combination of positive phototropism and a negative gravitropism.
E)   The stems actually were responding to the agar blocks that had been used in the experiments.F) A) and C)
G) A) and E)

Question 4

Research has shown that cytokinin levels fluctuate seasonally in temperate plants. What season would you expect to see the lowest levels of cytokinins and why would this be adaptive?

Accepted Answer

A)   Spring, because lower levels of cytokinin allow auxin to promote rapid growth the height for stems. This will allow the plant to compete effectively for sunlight.
B)   Summer, because lower levels of cytokinin would slow growth down and delay leaf aging. This will allow the plant to maximize the production of starch and increase it's sugar reserves. This will help ensure the plant's survival through Autumn and Winter.
C)   Autumn, because lower levels of cytokinin at this time of year will induce the production of ethylene. This will result in maturation of fruit and ensure effective seed dispersal before Winter.
D)   Winter, because lower levels of cytokinin will place buds into a dormant state. This will protect the underlying tissues from freezing until Spring.E) C) and D)
F) All of the above

Question 5

A plant is exposed to a toxin that blocks ABA receptor sites in the plasma membrane. What is the likely consequence of this exposure?

Accepted Answer

A)   Oxygen deprivation will trigger the release of ethylene, which will in turn suppress root growth.
B)   Gibberellin production will increase, allowing the plant to access more nutrients in the soil.
C)   ABA will enter the cells by an alternative route and normal function will be restored.
D)   The plant will lose excess water through transpiration and suffer dehydration.
E)   The guard cells will become flaccid and gas exchange will cease.F) C) and E)
G) None of the above

Question 6

You a given a plant tissue in lab and asked to determine if the tissue is a source or a sink. Microscopic analysis reveals an abundance of colorless parenchyma cells with plastids. Only one biochemical test reacts positively with your sample. In the presence of iodine, the plastids turn a dark purplish color. Based on this information you determine your sample is

Accepted Answer

A)   a source because your sample is rich in carbohydrates.
B)   a source because your sample contains plastids.
C)   a sink because your sample is rich in carbohydrates.
D)   both a source and sink because it contains both plastids and carbohydrates.E) B) and D)
F) B) and C)

Question 7

A scientist is investigating a hormone response in rose bush stems by removing the apical meristems of the main stems. What is the most likely result of this experiment and what hormone is responsible?

Accepted Answer

A)   New apical buds will develop under the influence of auxin.
B)   Larger, deeper roots will form under the influence of cytokinin.
C)   More leaf buds will appear along the main stems under the influence of auxin.
D)   Flowers will turn yellow and fall off under the influence of auxin.
E)   Lateral buds will develop under the influence of cytokinin.F) B) and D)
G) C) and D) E

Question 8

Plants maintain higher levels of phytochrome at their growing tips where phytochrome plays important roles in growth responses to light. Phytochrome levels are also high in areas of the plant that are "greening". What does this suggest about the role of phytochrome in these "greening" zones?

Accepted Answer

A)   Phytochrome is absorbing green wavelengths of light.
B)   In these areas, phytochrome is the first step in the electron transport chain of photosynthesis.
C)   Phytochrome is facilitating the transcription and translation of photosynthesis related proteins.
D)   Phytochrome is facilitating the migration of chlorophyll pigments from other areas of the plant.E) None of the above
F) All of the above

Question 9

Abscisic acid (ABA)  is synthesized in the roots in response to decreased soil water potential. ABA then translocates to the leaves, where it rapidly alters the osmotic potential of guard cells. What effect would this have on the stomata and the process of transpiration?

Accepted Answer

A)   The stomata would open thereby increasing the rate of transpiration.
B)   The stomata would open thereby decreasing the rate of transpiration.
C)   The stomata would close thereby decreasing the rate of transpiration.
D)   The stomata would close thereby increasing the rate of transpiration.
E)   The change in the stomata would have no effect on the rate of transpiration.F) D) and E)
G) A) and D)

Exam 26: The Living Plant

Some plants are able to endure frequent flooding events because they form

Correct Answer
verified
C

Halophytes are plants that live in saline soils. The high osmotic potential of the salt solution in the soil creates a very negative water potential. What can halophytes do so that water will flow into the roots?

Correct Answer
verified
C

Several scientists, including Charles and Francis Darwin, Frits Went and others, demonstrated that auxins caused stems to bend toward light in a series of elaborate experiments. Went was the researcher who finally determined that bending of the stem toward light was a result of which mechanism?

Correct Answer
verified

Research has shown that cytokinin levels fluctuate seasonally in temperate plants. What season would you expect to see the lowest levels of cytokinins and why would this be adaptive?

Correct Answer
verified

A plant is exposed to a toxin that blocks ABA receptor sites in the plasma membrane. What is the likely consequence of this exposure?

Correct Answer
verified

Correct Answer
verified

A scientist is investigating a hormone response in rose bush stems by removing the apical meristems of the main stems. What is the most likely result of this experiment and what hormone is responsible?

Correct Answer
verified
E

Plants maintain higher levels of phytochrome at their growing tips where phytochrome plays important roles in growth responses to light. Phytochrome levels are also high in areas of the plant that are "greening". What does this suggest about the role of phytochrome in these "greening" zones?

Correct Answer
verified

Abscisic acid (ABA) is synthesized in the roots in response to decreased soil water potential. ABA then translocates to the leaves, where it rapidly alters the osmotic potential of guard cells. What effect would this have on the stomata and the process of transpiration?

Correct Answer
verified

Exam 26: The Living Plant

Some plants are able to endure frequent flooding events because they form

Correct AnswerverifiedC

Halophytes are plants that live in saline soils. The high osmotic potential of the salt solution in the soil creates a very negative water potential. What can halophytes do so that water will flow into the roots?

Correct AnswerverifiedC

Several scientists, including Charles and Francis Darwin, Frits Went and others, demonstrated that auxins caused stems to bend toward light in a series of elaborate experiments. Went was the researcher who finally determined that bending of the stem toward light was a result of which mechanism?

Correct AnswerverifiedShow Answer

Research has shown that cytokinin levels fluctuate seasonally in temperate plants. What season would you expect to see the lowest levels of cytokinins and why would this be adaptive?

Correct AnswerverifiedShow Answer

A plant is exposed to a toxin that blocks ABA receptor sites in the plasma membrane. What is the likely consequence of this exposure?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

A scientist is investigating a hormone response in rose bush stems by removing the apical meristems of the main stems. What is the most likely result of this experiment and what hormone is responsible?

Correct AnswerverifiedE

Plants maintain higher levels of phytochrome at their growing tips where phytochrome plays important roles in growth responses to light. Phytochrome levels are also high in areas of the plant that are "greening". What does this suggest about the role of phytochrome in these "greening" zones?

Correct AnswerverifiedShow Answer

Abscisic acid (ABA) is synthesized in the roots in response to decreased soil water potential. ABA then translocates to the leaves, where it rapidly alters the osmotic potential of guard cells. What effect would this have on the stomata and the process of transpiration?

Correct AnswerverifiedShow Answer

Correct Answer
verified
C

Correct Answer
verified
C

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
E

Correct Answer
verified

Correct Answer
verified