Question 1

What happens to the guard cells as K+ and Cl- enter the cell?

Accepted Answer

A)  The water potential goes up (i.e., becomes less negative). 
B)  The water potential goes down (i.e., becomes more negative). 
C)  Water leaves by osmosis. 
D)  The stoma closes. 
E)  The guard cells shrink. 
A)  The water potential goes up (i.e., becomes less negative). 
B)  The water potential goes down (i.e., becomes more negative). 
C)  Water leaves by osmosis. 
D)  The stoma closes. 
E)  The guard cells shrink.

Question 2

Refer to the figure below.   This figure shows the interaction between bulk flow movement of materials in the phloem and the xylem.Which statement correctly identifies the locations where the water potential would be lowest (most negative) in each system?

Accepted Answer

A)  Upper end of xylem, upper end of phloem 
B)  Lower end of xylem, lower end of phloem 
C)  Upper end of xylem, lower end of phloem 
D)  Upper end of xylem vessels, lower end of phloem sieve tubes 
E)  Lower end of xylem vessels, upper end of phloem sieve tubes 
A)  Upper end of xylem, upper end of phloem 
B)  Lower end of xylem, lower end of phloem 
C)  Upper end of xylem, lower end of phloem 
D)  Upper end of xylem vessels, lower end of phloem sieve tubes 
E)  Lower end of xylem vessels, upper end of phloem sieve tubes

Question 3

If a tree is girdled when its leaves are expanded and photosynthetically active, the bark will swell in the region _______ the girdle, and the _______ will die before the rest of the tree.

Accepted Answer

A)  below; roots 
B)  below; branches 
C)  below; leaves 
D)  above; roots 
E)  above; branches 
A)  below; roots 
B)  below; branches 
C)  below; leaves 
D)  above; roots 
E)  above; branches

Question 4

The primary difference between the transportation via the xylem and translocation via the phloem is that translocation requires _______.

Accepted Answer

The answer of The primary difference between the transportation via...

Question 5

Which process accounts for the movement of water upward through a narrow tube?

Accepted Answer

A)  Adhesion of water molecules to the tube via hydrogen bonding 
B)  Negative water potential in the xylem 
C)  Active transport of water molecules 
D)  Passive osmosis of water following ion movement 
E)  Pumping of water into the phloem 
A)  Adhesion of water molecules to the tube via hydrogen bonding 
B)  Negative water potential in the xylem 
C)  Active transport of water molecules 
D)  Passive osmosis of water following ion movement 
E)  Pumping of water into the phloem

Question 6

Which of the following is true of roots?

Accepted Answer

A)  They function only as sources. 
B)  They function only as sinks. 
C)  They are neither sources nor sinks but function more like conduits. 
D)  They rely on nonliving vessels to transport phloem. 
E)  They can function either as sinks or as sources. 
A)  They function only as sources. 
B)  They function only as sinks. 
C)  They are neither sources nor sinks but function more like conduits. 
D)  They rely on nonliving vessels to transport phloem. 
E)  They can function either as sinks or as sources.

Question 7

Why do plants generally close their stomata at night?

Accepted Answer

There is no need to

Question 8

The plant cells that lose large amounts of water most directly and thus generate the low water potential that pulls water up from the roots are the

Accepted Answer

A)  mesophyll cells. 
B)  guard cells. 
C)  root hairs. 
D)  epidermal cells. 
E)  xylem cells. 
A)  mesophyll cells. 
B)  guard cells. 
C)  root hairs. 
D)  epidermal cells. 
E)  xylem cells.

Question 9

A cue for guard cells to actively pump protons out of the cell is _______.

Accepted Answer

The answer of A cue for guard cells to actively...

Question 10

Because the plant cuticle is waxy and impermeable to water, plants are faced with a need to balance which two survival needs?

Accepted Answer

When stomata are open, the pla

Question 11

Which statement about water transport in the xylem is true?

Accepted Answer

A)  Water is pumped up from the roots. 
B)  Water generally stops moving during drought conditions. 
C)  Water transport occurs in living cells. 
D)  Water in the xylem is under tension. 
E)  Water movement is independent of transpiration. 
A)  Water is pumped up from the roots. 
B)  Water generally stops moving during drought conditions. 
C)  Water transport occurs in living cells. 
D)  Water in the xylem is under tension. 
E)  Water movement is independent of transpiration.

Question 12

If you were to place a 1-meter capillary tube in a source of water, it would draw a small amount of water up the tube a relatively short distance.What critical forces work to draw water up trees that are missing from the capillary tube experiment?

Accepted Answer

In trees transpiration, tensio

Question 13

A botanist is curious about the contents of the phloem in a newly discovered relative of limes.The best way to obtain this information is to

Accepted Answer

A)  use tiny drills and capillary pipettes. 
B)  collect material from stylets of aphids that are infecting the tree. 
C)  obtain liquids oozing from cut lime stem surfaces. 
D)  collect droplets formed by guttation. 
E)  gather the tree's mycorrhizal fungi for subsequent analysis. 
A)  use tiny drills and capillary pipettes. 
B)  collect material from stylets of aphids that are infecting the tree. 
C)  obtain liquids oozing from cut lime stem surfaces. 
D)  collect droplets formed by guttation. 
E)  gather the tree's mycorrhizal fungi for subsequent analysis.

Question 14

Pure water is placed on either side of a semipermeable membrane through which water can pass.No net movement of water occurs because the water potential on each side has

Accepted Answer

A)  a negative pressure potential. 
B)  a negative water potential. 
C)  positive water potential. 
D)  the same water potential as the other side. 
E) an unstable pressure potential. 
A)  a negative pressure potential. 
B)  a negative water potential. 
C)  positive water potential. 
D)  the same water potential as the other side. 
E) an unstable pressure potential.

Question 15

An aphid is found drinking sugars and amino acids from a melon plant.Its stylet must have entered the

Accepted Answer

A)  phloem. 
B)  xylem. 
C)  pericycle. 
D)  endodermis. 
E)  guard cells. 
A)  phloem. 
B)  xylem. 
C)  pericycle. 
D)  endodermis. 
E)  guard cells.

Question 16

K+ ions initiate stomatal closing by means of

Accepted Answer

A)  active transport into the guard cells. 
B)  active transport out of the guard cells. 
C)  active transport from one guard cell to another. 
D)  diffusion into the guard cells. 
E)  diffusion out of the guard cells. 
A)  active transport into the guard cells. 
B)  active transport out of the guard cells. 
C)  active transport from one guard cell to another. 
D)  diffusion into the guard cells. 
E)  diffusion out of the guard cells.

Question 17

Which comes first in the uptake and transport of water on a sunny day: cohesion or tension?

Accepted Answer

A)  Cohesion 
B)  Tension 
C)  Both; they are simultaneous 
D)  Neither; adhesion can replace both 
E)  Neither; adhesion prevents both 
A)  Cohesion 
B)  Tension 
C)  Both; they are simultaneous 
D)  Neither; adhesion can replace both 
E)  Neither; adhesion prevents both

Question 18

Proton pumps pump H+ out of the cell to

Accepted Answer

A)  increase the acidity level outside the cell. 
B)  decrease the acidity level outside the cell. 
C)  rid the cell of K+ ions. 
D)  facilitate the acquisition of K+ ions. 
E)  facilitate the acquisition of water. 
A)  increase the acidity level outside the cell. 
B)  decrease the acidity level outside the cell. 
C)  rid the cell of K+ ions. 
D)  facilitate the acquisition of K+ ions. 
E)  facilitate the acquisition of water.

Question 19

Water potential is the highest (i.e., least negative)

Accepted Answer

A)  in the xylem of the roots. 
B)  in the xylem of the trunk. 
C)  inside the leaf. 
D)  just outside the leaf. 
E)  nowhere; water potential is constant throughout. 
A)  in the xylem of the roots. 
B)  in the xylem of the trunk. 
C)  inside the leaf. 
D)  just outside the leaf. 
E)  nowhere; water potential is constant throughout.

Question 20

The translocation of phloem sap requires energy to

Accepted Answer

A)  transfer water from the xylem. 
B)  drive sap along the sieve tube. 
C)  transfer water back from the phloem tube to the xylem. 
D)  transfer phloem sap from sink to source. 
E)  transport solutes from sieve tubes into sinks. 
A)  transfer water from the xylem. 
B)  drive sap along the sieve tube. 
C)  transfer water back from the phloem tube to the xylem. 
D)  transfer phloem sap from sink to source. 
E)  transport solutes from sieve tubes into sinks.

Exam 34: Transport in Plants

What happens to the guard cells as K+ and Cl- enter the cell?

Refer to the figure below. This figure shows the interaction between bulk flow movement of materials in the phloem and the xylem.Which statement correctly identifies the locations where the water potential would be lowest (most negative) in each system?

If a tree is girdled when its leaves are expanded and photosynthetically active, the bark will swell in the region _______ the girdle, and the _______ will die before the rest of the tree.

The primary difference between the transportation via the xylem and translocation via the phloem is that translocation requires _______.

Which process accounts for the movement of water upward through a narrow tube?

Which of the following is true of roots?

Why do plants generally close their stomata at night?

The plant cells that lose large amounts of water most directly and thus generate the low water potential that pulls water up from the roots are the

A cue for guard cells to actively pump protons out of the cell is _______.

Because the plant cuticle is waxy and impermeable to water, plants are faced with a need to balance which two survival needs?

Which statement about water transport in the xylem is true?

If you were to place a 1-meter capillary tube in a source of water, it would draw a small amount of water up the tube a relatively short distance.What critical forces work to draw water up trees that are missing from the capillary tube experiment?

A botanist is curious about the contents of the phloem in a newly discovered relative of limes.The best way to obtain this information is to

Pure water is placed on either side of a semipermeable membrane through which water can pass.No net movement of water occurs because the water potential on each side has

An aphid is found drinking sugars and amino acids from a melon plant.Its stylet must have entered the

K+ ions initiate stomatal closing by means of

Which comes first in the uptake and transport of water on a sunny day: cohesion or tension?

Proton pumps pump H+ out of the cell to

Water potential is the highest (i.e., least negative)

The translocation of phloem sap requires energy to

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What happens to the guard cells as K⁺ and Cl^- enter the cell?

If a tree is girdled when its leaves are expanded and photosynthetically active, the bark will swell in the region _ the girdle, and the _ will die before the rest of the tree.

K⁺ ions initiate stomatal closing by means of

Proton pumps pump H⁺ out of the cell to