Question 1

Which of the following best describes water potential ($$\Psi) $$and its role in plant water movement?

Accepted Answer

Water potential ($$\Psi) is $$the sum of solute potential and pressure potential, and water moves from areas of higher to lower water potential.

Question 2

A plant has a water potential of $$-1.4$$ MPa at the leaves, $$-3.2$$ MPa at the root tips, and the atmospheric water potential is $$-0.1$$ MPa. Will water move from the soil into the roots and up to the leaves? Why or why not?

Accepted Answer

Yes, because water moves from areas of higher (less negative) to lower (more negative) water potential, and the gradient supports upward movement.

Question 3

Which scenario best illustrates the difference between adhesion and cohesion in water transport within plants?

Accepted Answer

Cohesion allows water molecules to stick together, forming a continuous column in the xylem, while adhesion enables water to cling to the walls of xylem vessels, helping counteract gravity.

Question 4

Which of the following statements about osmosis is correct?

Accepted Answer

Osmosis is the passive movement of water across a selectively permeable membrane from an area of higher water potential to lower water potential.

Question 5

A plant root is placed in salty water. What is the most likely effect on the plant, and why?

Accepted Answer

The plant will lose water because the external solution has a lower water potential, causing water to move out of the root cells by osmosis.

Question 6

Which of the following best explains why bulk flow is used for long-distance transport in plants instead of diffusion?

Accepted Answer

Bulk flow is much faster than diffusion and can move large volumes of water and solutes over long distances efficiently.

Question 7

Which of the following is a function of guard cells in plant leaves?

Accepted Answer

They regulate the opening and closing of stomata, controlling gas exchange and water loss.

Question 8

Which of the following best describes the role of companion cells in phloem transport?

Accepted Answer

Companion cells assist sieve tube elements by loading and unloading sugars, providing metabolic support for translocation.

Question 9

Which of the following is a correct statement about the movement of sugars in the phloem?

Accepted Answer

Sugars move from source to sink via positive pressure generated by active loading of sugars into the phloem.

Question 10

Which of the following is NOT a macronutrient required by plants?

Accepted Answer

Iron (Fe)

Question 11

A plant is showing yellowing of its leaves (chlorosis). Which nutrient deficiency is most likely responsible, and why?

Accepted Answer

Nitrogen deficiency, because nitrogen is essential for chlorophyll synthesis.

Question 12

Which of the following best describes cation exchange in soils?

Accepted Answer

Cation exchange is the process by which positively charged ions are exchanged between soil particles and plant roots, often facilitated by the release of $$\mathrm{H}^+$$ ions from roots.

Question 13

Which of the following is a primary reason carnivorous plants have evolved the ability to capture and digest insects?

Accepted Answer

They often live in nutrient-poor soils and obtain essential nutrients, especially nitrogen, from their prey.

Question 14

Which of the following best describes double fertilization in angiosperms?

Accepted Answer

One sperm fertilizes the egg to form a zygote, while another sperm fuses with two polar nuclei to form the endosperm.

Question 15

Which of the following is a strategy angiosperms use to prevent self-fertilization?

Accepted Answer

Self-incompatibility, where the plant recognizes and rejects its own pollen.

Question 16

Which of the following is a correct statement about the difference between active and passive transport across a cell membrane?

Accepted Answer

Active transport requires energy (ATP) to move substances against their concentration gradient, while passive transport does not require energy and moves substances down their gradient.

Question 17

Which of the following best explains why soil is considered a finite resource?

Accepted Answer

Soil formation is a slow process, and excessive use or erosion can deplete it faster than it can be replaced.

Question 18

Which of the following is a correct statement about the main method of GMO production in plants?

Accepted Answer

The Agrobacterium tumefaciens method introduces foreign DNA into plant cells, which are then selected and regenerated into whole plants.

Question 19

Which plant hormone is primarily responsible for cell elongation and phototropism, and where is it produced?

Accepted Answer

Auxin, produced in the shoot apical meristem.

Comprehensive Study Guidance for Plant Biology: Water Transport, Nutrition, Reproduction, and Biotechnology

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