Question 1

Which of the following best explains why mosses do not grow as tall as trees?

Accepted Answer

Mosses lack vascular tissue and lignin.

Question 2

In vascular plants, which structure is primarily responsible for the upward transport of water from roots to leaves?

Accepted Answer

Xylem

Question 3

Which of the following statements about water potential ($$\Psi) is $$correct?

Accepted Answer

Water moves from regions of higher $$\Psi to $$regions of lower $$\Psi.$$

Question 4

A plant cell with $$\Psi_S = -0.7$$ MPa and $$\Psi_P = 0.5$$ MPa is placed in pure water ($$\Psi = 0$$ MPa). What is the direction of net water movement?

Accepted Answer

Water will move into the cell.

Question 5

Which pathway allows water and minerals to move through dead tissue in plants?

Accepted Answer

Apoplastic route

Question 6

What would happen to sucrose transport in the phloem if the proton pump stopped working?

Accepted Answer

Sucrose transport would decrease because the proton gradient is required for co-transport.

Question 7

Which equation correctly describes the relationship between water potential, solute potential, and pressure potential?

Accepted Answer

$$\Psi = \Psi_S + \Psi_P$$

Question 8

If a plant cell is placed in a solution with a lower water potential than the cell, what will happen?

Accepted Answer

The cell will lose water and become plasmolyzed.

Question 9

Which of the following is a direct result of transpiration in plants?

Accepted Answer

Upward movement of water through the xylem

Question 10

Which process is responsible for the movement of water across a selectively permeable membrane from an area of low solute concentration to high solute concentration?

Accepted Answer

Osmosis

Question 11

What is the main driving force for bulk flow of water in the xylem of tall trees?

Accepted Answer

Evaporation of water from leaves (transpiration)

Question 12

Which of the following best describes the cohesion-adhesion theory?

Accepted Answer

Water molecules stick to each other (cohesion) and to cell walls (adhesion), allowing upward movement in xylem.

Question 13

Which of the following would most likely cause cavitation in the xylem?

Accepted Answer

Breakage of hydrogen bonds between water molecules

Question 14

Which of the following is true about the opening and closing of stomata?

Accepted Answer

Stomata open when guard cells take up potassium ions and water follows by osmosis.

Question 15

Which plant tissue is responsible for transporting sugars from source to sink?

Accepted Answer

Phloem

Question 16

A farmer removes flowers from a crop to increase the size of tubers. What is the physiological explanation for this practice?

Accepted Answer

Removing flowers redirects sugars from reproductive organs (sink) to tubers (sink), increasing tuber size.

Question 17

Which of the following equations correctly calculates the solute potential ($$\Psi_S) in $$plant cells?

Accepted Answer

$$\Psi_S = -iCRT$$

Question 18

If the ionization constant ($$i) $$for NaCl is 2, the molarity ($$C) is 0.2 $$mol/L, the ideal gas constant ($$R) is 8.32 J K$^{-1}$$ mol$$^{-1}$$, and the temperature ($$T) is 298 K$$, what is the solute potential ($$\Psi_S$$)?

Accepted Answer

$$\Psi_S = -2 	imes 0.2 	imes 8.32 	imes 298 = -991.23 J/L$$

Question 19

Which of the following is NOT transported in the phloem?

Accepted Answer

Mineral nutrients from soil

Topic7B Plant Growth and Transport: Physiology and Cell Biology Study Notes

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