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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. 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.

2. 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.

3. What creates the high hydrostatic pressure at the source end of a sieve tube in the pressure-flow model?

  1. Active pumping of oxygen into phloem
  2. Inflow of water by osmosis following active sucrose loading
  3. Evaporation of water through open stomatal pores
  4. Movement of starch into companion cells
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Answer: B

Inflow of water from adjacent xylem vessels into high-sucrose sieve tubes creates high hydrostatic pressure driving mass flow.

4. 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.

5. 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.

6. 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.

7. Which living cells provide metabolic support and ATP energy to mature sieve tube elements?

  1. Tracheids
  2. Companion cells
  3. Epidermal hair cells
  4. Guard cells
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Answer: B

Companion cells contain abundant mitochondria and supply metabolic energy (ATP) needed for active sucrose loading into sieve tubes.

8. Under which conditions is guttation most likely to occur?

  1. Hot, windy, and dry sunny afternoon
  2. Cool, highly humid night with moist soil
  3. Freezing winter conditions with dry air
  4. Bright daylight with fully open stomata
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Answer: B

Guttation requires high soil moisture and high atmospheric humidity combined with low transpiration rates, typical of cool nights.

9. What function does the Casparian strip serve in the root endodermis?

  1. It blocks the apoplast pathway, forcing water and ions through the symplast pathway.
  2. It secretes digestive enzymes into soil space.
  3. It accelerates water uptake via capillary action.
  4. It prevents transpiration loss from root epidermis.
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Answer: A

The waxy suberin Casparian strip blocks extracellular apoplastic water flow, forcing water into selective endodermal protoplasts.

10. 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.

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