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Quiz Chapter 4: Transport in Plants

10 questions · Form 5 Biology Bab 3: Transport in Plants

10 questions · plays in fullscreen

Full Question List & Answer Key

Prefer reading to quizzing? All 10 questions are listed below with the answer and explanation under each one.

1. During phloem loading, what occurs immediately after sucrose is actively loaded into sieve tube elements at the source?

  1. Water potential in sieve tubes drops, causing water to enter from xylem by osmosis.
  2. Hydrostatic pressure in sieve tubes decreases to zero.
  3. Stomata close instantly to prevent water vapor loss.
  4. Phloem sap freezes and forms solid starch granules.
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Answer: A

Active sucrose loading increases solute concentration, lowering water potential and drawing water in from neighboring xylem by osmosis.

2. How does water move from cell to cell via the symplast pathway in root cortex cells?

  1. By moving along external cell walls only
  2. Through cytoplasmic connections called plasmodesmata
  3. Via active transport protein pumps in cutin layers
  4. By bulk flow driven by mechanical contraction
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Answer: B

The symplast pathway involves water moving through continuous living cytoplasm linked across adjacent cells via plasmodesmata.

3. What phenomenon causes droplets of water to exude from hydathodes at leaf margins?

  1. Transpiration
  2. Guttation
  3. Plasmolysis
  4. Translocation
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Answer: B

Guttation occurs under high humidity and high root pressure, forcing liquid water out through specialized leaf margins pores called hydathodes.

4. What is the key advantage of phytoremediation compared to traditional chemical soil cleanup techniques?

  1. It removes all toxic metals within minutes.
  2. It is environmentally friendly, cost-effective, and preserves soil fertility.
  3. It completely eliminates the need for solar radiation.
  4. It converts all toxic metals directly into atmospheric nitrogen gas.
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Answer: B

Phytoremediation uses natural plant metabolic systems, making it sustainable, cost-effective, and non-destructive to soil ecology.

5. What is the primary organic solute transported during translocation in phloem?

  1. Glucose
  2. Starch
  3. Sucrose
  4. Glycogen
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Answer: C

Sucrose is a non-reducing disaccharide that is soluble, stable, and reactive-neutral, making it the primary solute transported in phloem sap.

6. Which structural modification enables xylem vessel elements to withstand negative pressure without collapsing?

  1. Suberin rings in the middle lamella
  2. Lignified secondary cell walls
  3. Perforated sieve plates with companion cells
  4. Thick waxy cutin layers
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Answer: B

Lignin deposition in xylem cell walls provides immense structural strength, preventing collapse during strong transpirational tension.

7. Which property of water allows it to adhere to the inner lignified walls of xylem vessels?

  1. Adhesion
  2. Cohesion
  3. Viscosity
  4. Surface tension
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Answer: A

Adhesion is the attractive force between polar water molecules and hydrophilic xylem walls, preventing water column slippage.

8. Which forces maintain a continuous, unbroken column of water in narrow xylem vessels during transpiration?

  1. Gravity and root pressure
  2. Cohesion between water molecules and adhesion to xylem walls
  3. Active transport and endosmosis
  4. Phloem mass flow and stomatal resistance
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Answer: B

Cohesion (H-bonding between water molecules) and adhesion (attraction between water and xylem wall) keep the transpiration stream intact.

9. Which route allows water movement purely through non-living cell walls and intercellular spaces?

  1. Symplast pathway
  2. Apoplast pathway
  3. Vacuolar pathway
  4. Phloem pathway
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Answer: B

The apoplast pathway involves water moving along hydrophilic porous cell walls and spaces without crossing plasma membranes.

10. Which plant species is commonly used in phytoremediation to absorb heavy metals and radioactive pollutants from soil?

  1. Helianthus annuus (Sunflower)
  2. Cuscuta sp. (Dodder)
  3. Asplenium nidus (Bird's nest fern)
  4. Nepenthes sp. (Pitcher plant)
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Answer: A

Sunflowers (Helianthus annuus) are renowned phytoremediators capable of absorbing heavy metals and radioactive compounds from contaminated soil.

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