Question 1

Which of the following statements about water transport in roots to the xylem is false?

Accepted Answer

A)  Water may reach the xylem by an entirely apoplastic route. 
B)  Water can move by bulk flow. 
C)  Water must be transported across at least one membrane. 
D)  Water may be transported symplastically. 
E)  Water cannot penetrate the Casparian strips. 
A)  Water may reach the xylem by an entirely apoplastic route. 
B)  Water can move by bulk flow. 
C)  Water must be transported across at least one membrane. 
D)  Water may be transported symplastically. 
E)  Water cannot penetrate the Casparian strips. A

Question 2

Water tends to move into a cell that has

Accepted Answer

A)  a high turgor pressure due to cell wall rigidity. 
B)  a high, positive water potential. 
C)  an interior solute concentration like that of distilled water. 
D)  a more negative water potential than its surroundings. 
E)  reached equilibrium. 
A)  a high turgor pressure due to cell wall rigidity. 
B)  a high, positive water potential. 
C)  an interior solute concentration like that of distilled water. 
D)  a more negative water potential than its surroundings. 
E)  reached equilibrium. D

Question 3

Which of the following processes can take place even without the presence of living cells?

Accepted Answer

A)  Osmosis 
B)  Transpiration 
C)  Translocation 
D)  Active transport 
E)  Facilitated diffusion 
A)  Osmosis 
B)  Transpiration 
C)  Translocation 
D)  Active transport 
E)  Facilitated diffusion A

Question 4

Which statement about phloem transport is not true?

Accepted Answer

A)  It takes place in sieve tubes. 
B)  It depends on mechanisms for loading solutes into the phloem at sources. 
C)  It stops if the phloem is killed by heat. 
D)  A high pressure potential is maintained in the sieve tubes. 
E)  At sinks, solutes are actively transported into sieve tube elements. 
A)  It takes place in sieve tubes. 
B)  It depends on mechanisms for loading solutes into the phloem at sources. 
C)  It stops if the phloem is killed by heat. 
D)  A high pressure potential is maintained in the sieve tubes. 
E)  At sinks, solutes are actively transported into sieve tube elements.

Question 5

The Casparian strip is

Accepted Answer

A)  a layer of endodermal cells. 
B)  a layer of epidermal cells. 
C)  the apoplast. 
D)  the symplast. 
E)  the waxy region of the endodermal cell walls. 
A)  a layer of endodermal cells. 
B)  a layer of epidermal cells. 
C)  the apoplast. 
D)  the symplast. 
E)  the waxy region of the endodermal cell walls.

Question 6

The fibrous protein in sieve tube elements

Accepted Answer

A)  may plug leaks when a plant is damaged. 
B)  clogs the sieve plates at all times. 
C)  never clogs the sieve plates. 
D)  serves no known function. 
E)  provides the driving force for transport in the phloem. 
A)  may plug leaks when a plant is damaged. 
B)  clogs the sieve plates at all times. 
C)  never clogs the sieve plates. 
D)  serves no known function. 
E)  provides the driving force for transport in the phloem.

Question 7

Water potential

Accepted Answer

A)  is the difference between the solute potential and the pressure potential. 
B)  is analogous to the air pressure in an automobile tire. 
C)  is the movement of water through a membrane. 
D)  determines the direction of water movement between cells. 
E)  is defined as 1.0 MPa for pure water under no applied pressure. 
A)  is the difference between the solute potential and the pressure potential. 
B)  is analogous to the air pressure in an automobile tire. 
C)  is the movement of water through a membrane. 
D)  determines the direction of water movement between cells. 
E)  is defined as 1.0 MPa for pure water under no applied pressure.

Question 8

Which of the following statements about xylem transport and phloem transport is true?

Accepted Answer

A)  Both are passive processes that do not require energy from the plant. 
B)  Both rely on only living cells. 
C)  Both rely on a water potential gradient. 
D)  The direction of flow can reverse in both. 
E)  The driving force for both is in the leaves. 
A)  Both are passive processes that do not require energy from the plant. 
B)  Both rely on only living cells. 
C)  Both rely on a water potential gradient. 
D)  The direction of flow can reverse in both. 
E)  The driving force for both is in the leaves.

Question 9

In the pressure flow model of translocation, the movement of water by osmosis occurs

Accepted Answer

A)  from the xylem to the phloem at the sink. 
B)  from the phloem to the xylem at the source. 
C)  from the xylem to the phloem at the source. 
D)  in both directions at the sink. 
E)  None of the above 
A)  from the xylem to the phloem at the sink. 
B)  from the phloem to the xylem at the source. 
C)  from the xylem to the phloem at the source. 
D)  in both directions at the sink. 
E)  None of the above

Question 10

Use the following to answer questions :
Refer to the diagram below, depicting vascular tissue of a stem.  
-Is the greater (less negative) pressure potential located in the upper phloem sieve tubes or the lower phloem sieve tubes?

Accepted Answer

Upper phlo

Question 11

The concentration of sucrose in phloem sap can be as high as 0.5 M. The loading of sucrose into the phloem sieve tube element

Accepted Answer

A)  does not require energy. 
B)  directly uses the energy supplied by ATP hydrolysis. 
C)  is linked to K+ movement into the companion cell. 
D)  is linked to proton uptake (proton-sucrose symport). 
E)  is linked to proton-sucrose antiport. 
A)  does not require energy. 
B)  directly uses the energy supplied by ATP hydrolysis. 
C)  is linked to K+ movement into the companion cell. 
D)  is linked to proton uptake (proton-sucrose symport). 
E)  is linked to proton-sucrose antiport.

Question 12

Sugars move from the sieve tubes into the plant's tissue

Accepted Answer

A)  by diffusion. 
B)  via the apoplast. 
C)  by active transport. 
D)  by osmosis. 
E)  via translocation. 
A)  by diffusion. 
B)  via the apoplast. 
C)  by active transport. 
D)  by osmosis. 
E)  via translocation.

Question 13

Which statement is not true?

Accepted Answer

A)  The symplast consists of the interconnected cytoplasm of living cells. 
B)  Water can enter the stele without entering the symplast. 
C)  The Casparian strips prevent water from moving between endodermal cells. 
D)  The endodermis is a cell layer in the cortex. 
E)  Water can move freely in the apoplast without entering cells. 
A)  The symplast consists of the interconnected cytoplasm of living cells. 
B)  Water can enter the stele without entering the symplast. 
C)  The Casparian strips prevent water from moving between endodermal cells. 
D)  The endodermis is a cell layer in the cortex. 
E)  Water can move freely in the apoplast without entering cells.

Question 14

In most plants, the stomata at night are

Accepted Answer

A)  open to take in water. 
B)  open to take in CO2. 
C)  closed to prevent water loss. 
D)  closed to prevent CO2 loss. 
E)  closed to exclude O2. 
A)  open to take in water. 
B)  open to take in CO2. 
C)  closed to prevent water loss. 
D)  closed to prevent CO2 loss. 
E)  closed to exclude O2.

Question 15

Within the stele, _______ cells help transport mineral ions from the symplast into the apoplast, and water follows osmotically.

Accepted Answer

The answer of Within the stele, _______ cells help transport...

Question 16

Mineral ions move in the xylem

Accepted Answer

A)  passively. 
B)  by means of active transport. 
C)  by osmosis. 
D)  because of root pressure. 
E)  by means of the pumping action of various cells. 
A)  passively. 
B)  by means of active transport. 
C)  by osmosis. 
D)  because of root pressure. 
E)  by means of the pumping action of various cells.

Question 17

Per Scholander used _______ to measure tension in xylem sap.

Accepted Answer

A)  a balloon in a bell jar 
B)  a water column 
C)  an aphid 
D)  a barometer 
E)  a pressure chamber 
A)  a balloon in a bell jar 
B)  a water column 
C)  an aphid 
D)  a barometer 
E)  a pressure chamber

Question 18

Osmosis

Accepted Answer

A)  requires energy. 
B)  is the movement of water across a membrane from low solute concentration to high solute concentration. 
C)  is the movement of water across a membrane from high solute concentration to low solute concentration. 
D)  is the movement of solutes across the membrane. 
E)  is facilitated in plant cells by the pressure potential (turgor pressure). 
A)  requires energy. 
B)  is the movement of water across a membrane from low solute concentration to high solute concentration. 
C)  is the movement of water across a membrane from high solute concentration to low solute concentration. 
D)  is the movement of solutes across the membrane. 
E)  is facilitated in plant cells by the pressure potential (turgor pressure).

Question 19

Which process makes the water potential in a leaf more negative?

Accepted Answer

A)  The pressure placed on the leaf by the cuticle 
B)  The evaporation of water from mesophyll cells 
C)  The movement of water into the leaf by root pressure 
D)  The increased K+ pumped out of guard cells 
E)  The movement of water from the veins into the leaf 
A)  The pressure placed on the leaf by the cuticle 
B)  The evaporation of water from mesophyll cells 
C)  The movement of water into the leaf by root pressure 
D)  The increased K+ pumped out of guard cells 
E)  The movement of water from the veins into the leaf

Question 20

What is the process by which movement of K+ ions initiates stomatal closing?

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

Exam 35: Transport in Plants

Which of the following statements about water transport in roots to the xylem is false?

Water tends to move into a cell that has

Which of the following processes can take place even without the presence of living cells?

Which statement about phloem transport is not true?

The Casparian strip is

The fibrous protein in sieve tube elements

Water potential

Which of the following statements about xylem transport and phloem transport is true?

In the pressure flow model of translocation, the movement of water by osmosis occurs

Use the following to answer questions : Refer to the diagram below, depicting vascular tissue of a stem. -Is the greater (less negative) pressure potential located in the upper phloem sieve tubes or the lower phloem sieve tubes?

The concentration of sucrose in phloem sap can be as high as 0.5 M. The loading of sucrose into the phloem sieve tube element

Sugars move from the sieve tubes into the plant's tissue

Which statement is not true?

In most plants, the stomata at night are

Within the stele, _______ cells help transport mineral ions from the symplast into the apoplast, and water follows osmotically.

Mineral ions move in the xylem

Per Scholander used _______ to measure tension in xylem sap.

Osmosis

Which process makes the water potential in a leaf more negative?

What is the process by which movement of K+ ions initiates stomatal closing?

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What is the process by which movement of K⁺ ions initiates stomatal closing?