Question 1

Which root system is shown in the first image, and what is its primary advantage for plants in shallow soils?

Accepted Answer

Fibrous root system; increases surface area for absorption

Question 2

What is the main function of root hairs as seen in the third and fourth images?

Accepted Answer

Increasing the surface area for water and mineral absorption

Question 3

Which tissue type is responsible for conducting water and dissolved substances in roots, as shown in the cross-section images?

Accepted Answer

Vascular tissue

Question 4

The Casparian strip, as illustrated in the diagrams, is primarily composed of which substance and serves what function?

Accepted Answer

Suberin; blocks apoplastic flow of water and solutes

Question 5

Which of the following best describes the apoplast route for water movement in plant roots?

Accepted Answer

Movement through cell walls and spaces between cells, avoiding membranes

Question 6

A plant cell with a solute potential $$\Psi_s = -0.7$$ MPa and a pressure potential $$\Psi_p = 0.5$$ MPa is placed in a solution with $$\Psi_w = -0.2$$ MPa. What will happen to the cell?

Accepted Answer

There will be no net movement of water

Question 7

Which equation correctly represents the total water potential ($$\Psi_w) of a $$plant cell?

Accepted Answer

$$\Psi_w = \Psi_p + \Psi_s$$

Question 8

If a plant cell is placed in pure water ($$\Psi_w = 0$$ MPa), what will happen to the cell?

Accepted Answer

Water will enter the cell, increasing turgor pressure

Question 9

What is the role of aquaporins in plant cells, as shown in the relevant diagram?

Accepted Answer

They facilitate faster diffusion of water across membranes

Question 10

Which region of the root is primarily responsible for sensing gravity and protecting the growing tip?

Accepted Answer

Root cap

Question 11

A plant is growing in soil with a water potential of $$-0.1$$ MPa. If the root cell's water potential is $$-0.3$$ MPa, in which direction will water move?

Accepted Answer

From the soil into the root cell

Question 12

Which of the following best explains why solute potential ($$\Psi_s) is $$always negative in plant cells?

Accepted Answer

Solutes decrease the free energy of water

Question 13

What is the main function of the endodermis in plant roots?

Accepted Answer

To regulate the movement of water and minerals into the vascular tissue

Question 14

Which of the following scenarios would most likely result in plasmolysis of a plant cell?

Accepted Answer

Placing the cell in a hypertonic sucrose solution

Question 15

Which route allows the greatest control over the movement of water and solutes into the xylem?

Accepted Answer

Transmembrane route

Question 16

If a plant cell has $$\Psi_s = -0.5$$ MPa and $$\Psi_p = 0.3$$ MPa, what is its total water potential ($$\Psi_w$$)?

Accepted Answer

$$\Psi_w = -0.2$$ MPa

Question 17

Which of the following is NOT a function of the root cap?

Accepted Answer

Absorbing water and minerals

Question 18

Why do solutions outside the cell that are not contained by a membrane always have a pressure potential ($$\Psi_p) of 0 $$MPa?

Accepted Answer

They cannot develop turgor pressure

Question 19

Which structure in the root is responsible for the initiation of lateral roots?

Accepted Answer

Pericycle

Question 20

A plant cell is placed in a solution with $$\Psi_w = -0.5$$ MPa. The cell's $$\Psi_w is$$ $$-0.2$$ MPa. What will happen?

Accepted Answer

Water will move out of the cell

Water in Plant Life: Absorption, Transpiration, and Translocation

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