Question 1

The flow of K+ and Cl- into guard cells is facilitated by

Accepted Answer

A)   the absence of light.
B)   the outflow of protons from the guard cells.
C)   osmosis.
D)   negative water potential.
E)   the availability of CO2.

Question 2

Bulk flow of water through xylem is stopped by

Accepted Answer

A)   metabolic inhibitors.
B)   closed stomata.
C)   accumulation of K+ in guard cells.
D)   blue light.
E)   surface tension.

Question 3

Water enters the xylem tissue from surrounding root cells via

Accepted Answer

A)   active transport.
B)   facilitated diffusion.
C)   osmosis.
D)   pressure pumping.
E)   guttation.

Question 4

When water enters the cell and the pressure potential balances the solute potential, the cell is said to be _______.

Accepted Answer

The answer of When water enters the cell and the...

Question 5

Were it not for leaves, which of the following would most likely happen to water in the xylem?

Accepted Answer

A)   It would be drawn upward in the xylem but would not evaporate.
B)   It would flow normally up the xylem but at a decreased rate.
C)   It would flow more quickly upward through the xylem.
D)   It would flow upward in the trunk but no farther.
E)   It would move into the xylem at the roots but not progress any farther.

Question 6

Experiments with aphids have shown that phloem sap

Accepted Answer

A)   does not require living cells.
B)   flows at a rate of about 10 cm per hour.
C)   is passively transported.
D)   is predominantly sucrose.
E)   requires a living aphid to draw it from the tree.

Question 7

All of the following play a role in the closing of stomata except

Accepted Answer

A)   abscisic acid.
B)   the diffusion of K+ and Cl- ions.
C)   the absence of light.
D)   the pumping out of protons from the guard cell.
E)   the outward flow of water from the guard cell.

Question 8

Which of the following is true regarding loading and unloading in phloem translocation?

Accepted Answer

A)   Loading refers mainly to transfer of water, whereas unloading refers to the transfer of sucrose.
B)   Both require energy.
C)   Loading involves the transfer of phloem to the leaves, whereas unloading refers to the transfer of the products of photosynthesis to the roots.
D)   Loading requires active transport, whereas unloading requires only passive transport.
E)   Loading is associated with sinks, whereas unloading is associated with sources.

Question 9

The pumping of protons (H+)  out of a cell can trigger the movement of

Accepted Answer

A)   K+ out of the cell and Cl- into the cell.
B)   K+ into the cell and Cl- out of the cell.
C)   both K+ and Cl- out of the cell.
D)   both K+ and Cl- into the cell.
E)   K+ into the cell, with no movement of Cl-.

Question 10

As water enters a cell, turgor pressure increases because

Accepted Answer

A)   the cell's ability to take in solutes decreases.
B)   wilting pressure decreases.
C)   the cell wall resists swelling.
D)   water potential increases.
E)   osmotic pressure decreases.

Question 11

In the late 19th century, scientists performed an experiment in which a tree's roots were removed and the tree was placed in a vat of poison.The scientists were trying to test the hypothesis that roots were somehow responsible for pumping water through the tree to the roots.What did they discover?

Accepted Answer

A)   Nothing happened, indicating that roots do indeed pump water.
B)   Poison flowed through the tree but at a very slow rate, indicating that roots are responsible for a portion of the flow of water.
C)   Poison flowed through the tree until it killed the leaves, then stopped, indicating that leaves are critical to the flow of water.
D)   Poison flowed until it reached the xylem, then stopped, indicating that xylem effectively pumps water through the tree.
E)   Poison flowed until it reached the apoplast, indicating that the apoplast is largely responsible for the movement of water through the tree.

Question 12

Which experimental observation contributed to a better understanding of translocation in the phloem?

Accepted Answer

A)   Positive pressure in the xylem forced liquid out of cut aphid stylets.
B)   Positive pressure in the phloem forced liquid out of cut aphid stylets.
C)   Negative pressure in the xylem drew liquid in from cut aphid stylets.
D)   Negative pressure in the phloem drew liquid in from cut aphid stylets.
E)   Positive pressure in the xylem drew liquid in from cut aphid stylets.

Question 13

As a tree begins transpiring in the morning, tension occurs first in the

Accepted Answer

A)   branches.
B)   leaves.
C)   trunk.
D)   roots.
E)   bark.

Question 14

Researchers studying the effects of uncontrolled water movement within roots might create mutant plants that lack Casparian strips, or _______, in the endodermis.These plants would not be able to prevent water and ions from moving through the cell wall space between cells.

Accepted Answer

The answer of Researchers studying the effects of uncontrolled water...

Question 15

Which statement is true regarding the distinction between monocots and eudicots?

Accepted Answer

A)   Monocots lack guard cells.
B)   Monocots typically have fewer stomata.
C)   Monocots typically have specialized epidermal cells associated with guard cells.
D)   Monocots lack proton pumps in their guard cells.
E)   Monocots are not as sensitive to changes in light levels.

Question 16

Casparian strips are _______ layers in walls of _______ cells in roots.

Accepted Answer

A)   waxy; pericycle
B)   lignin; endodermal
C)   waxy; endodermal
D)   lignin; cortex
E)   waxy; epidermal

Question 17

Without a Casparian strip, which of the following would likely take place?

Accepted Answer

A)   Water and solutes would pass freely from endodermal cells to cortex cells.
B)   Water would not be taken up by the roots.
C)   Active transport would cease.
D)   Water and solutes from the apoplast would not be able to reach the endodermis.
E)   Solutes would remain in the symplast.

Question 18

A plant cell placed in distilled water will

Accepted Answer

A)   expand until the solute potential reaches that of the distilled water.
B)   become more turgid until the solute potential reaches that of the distilled water.
C)   become less turgid until the solute potential reaches that of the distilled water.
D)   become more turgid until the pressure potential of the cell reaches its solute potential.
E)   become less turgid until the pressure potential of the cell reaches the outside water potential.

Question 19

Which of the following statements about the movement of potassium ions is true?

Accepted Answer

A)   K+ enters guard cells, water follows, and the cells become turgid.
B)   K+ leaves guard cells, and they become less turgid.
C)   K+ enters guard cells, and they become less turgid.
D)   K+ leaves guard cells, and they become turgid.
E)   K+ reaches equilibrium in guard cells and their surroundings.

Question 20

Which structure of the leaf most minimizes water loss?

Accepted Answer

A)   Cortex
B)   Epidermis
C)   Cuticle
D)   Phloem
E)   Xylem

Exam 34: Transport in Plants

Were it not for leaves, which of the following would most likely happen to water in the xylem?

Correct AnswerverifiedShow Answer

Experiments with aphids have shown that phloem sap

Correct AnswerverifiedShow Answer

Researchers studying the effects of uncontrolled water movement within roots might create mutant plants that lack Casparian strips, or _______, in the endodermis.These plants would not be able to prevent water and ions from moving through the cell wall space between cells.

Correct AnswerverifiedShow Answer

Without a Casparian strip, which of the following would likely take place?

Correct AnswerverifiedShow Answer

Water enters the xylem tissue from surrounding root cells via

Correct AnswerverifiedShow Answer

Which of the following is true regarding loading and unloading in phloem translocation?

Correct AnswerverifiedShow Answer

As water enters a cell, turgor pressure increases because

Correct AnswerverifiedShow Answer

As a tree begins transpiring in the morning, tension occurs first in the

Correct AnswerverifiedShow Answer

Which statement is true regarding the distinction between monocots and eudicots?

Correct AnswerverifiedShow Answer

Bulk flow of water through xylem is stopped by

Correct AnswerverifiedShow Answer

All of the following play a role in the closing of stomata except

Correct AnswerverifiedShow Answer

The flow of K+ and Cl- into guard cells is facilitated by

Correct AnswerverifiedShow Answer

When water enters the cell and the pressure potential balances the solute potential, the cell is said to be _______.

Correct AnswerverifiedShow Answer

A plant cell placed in distilled water will

Correct AnswerverifiedShow Answer

Which structure of the leaf most minimizes water loss?

Correct AnswerverifiedShow Answer

The pumping of protons (H+) out of a cell can trigger the movement of

Correct AnswerverifiedShow Answer

Which of the following statements about the movement of potassium ions is true?

Correct AnswerverifiedShow Answer

Which experimental observation contributed to a better understanding of translocation in the phloem?

Correct AnswerverifiedShow Answer

In the late 19th century, scientists performed an experiment in which a tree's roots were removed and the tree was placed in a vat of poison.The scientists were trying to test the hypothesis that roots were somehow responsible for pumping water through the tree to the roots.What did they discover?

Correct AnswerverifiedShow Answer

Casparian strips are _______ layers in walls of _______ cells in roots.

Correct AnswerverifiedShow Answer

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The flow of K⁺ and Cl^- into guard cells is facilitated by

Correct Answer
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The pumping of protons (H⁺) out of a cell can trigger the movement of

Correct Answer
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Casparian strips are _ layers in walls of _ cells in roots.

Correct Answer
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