Lesson 3.1.3b

3.1.3b Water movement and adaptations to water availability Quiz: OCR Biology, Unit 2

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 3.1.3b, Water movement and adaptations to water availability: 20 multiple choice questions for the OCR Biology (H020), Unit 2: Exchange and transport, written with Revision Ninja.

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The 20 questions

  1. Which pathway of water movement passes through cell walls and intercellular spaces without crossing a cell membrane?

    • Transpiration stream pathway
    • Translocation pathway
    • Apoplast pathway
    • Symplast pathway

  2. Which pathway moves water through cell cytoplasm linked by plasmodesmata?

    • Apoplast pathway
    • Symplast pathway
    • Casparian pathway
    • Phloem pathway

  3. What term describes the attraction between water molecules in xylem?

    • Tension
    • Capillarity
    • Adhesion
    • Cohesion

  4. What term describes the attraction between water molecules and xylem walls?

    • Osmosis
    • Adhesion
    • Tension
    • Cohesion

  5. What is the continuous flow of water through a plant called?

    • Translocation flow
    • Apoplast pathway
    • Symplast pathway
    • Transpiration stream

  6. What is the water potential of pure water at standard conditions?

    • +100 kPa
    • -1000 kPa
    • 0 kPa
    • -100 kPa

  7. How does adding solute affect the water potential of a solution?

    • Makes it positive
    • Makes it lower
    • Makes it higher
    • Keeps it zero

  8. Cell A is -200 kPa and cell B is -500 kPa. Where does water move?

    • A to B
    • B to A
    • No net movement
    • Into cell A

  9. A cell (-600 kPa) is in a solution (-200 kPa). Which way does water move?

    • No net movement
    • Equally both ways
    • Out of cell
    • Into the cell

  10. Which leaf adaptation traps humid air to reduce transpiration in xerophytes?

    • Sunken stomata
    • Thin cuticles
    • Broad leaves
    • Stomata on top

  11. Where are stomata located on leaves of floating hydrophytes?

    • Upper surface only
    • Inside leaf pits
    • Lower surface only
    • Both surfaces equally

  12. What is the main benefit of leaf rolling in marram grass?

    • Traps humid air
    • Reduces root growth
    • Increases light absorption
    • Increases stomata number

  13. Which route of water loss is directly reduced by a thick waxy cuticle?

    • Stomatal transpiration
    • Symplastic transport
    • Cuticular evaporation
    • Apoplastic flow

  14. What primary benefit do cactus spines provide to limit water loss?

    • Increased surface area
    • Trapped oxygen layer
    • Enhanced photosynthesis
    • Reduced surface area

  15. Which root layer forces apoplastic water into the symplast pathway?

    • Endodermis
    • Epidermis
    • Cortex
    • Pericycle

  16. Which combined forces maintain an unbroken water column in xylem under tension?

    • Osmosis and diffusion
    • Turgor and tension
    • Cohesion and adhesion
    • Active transport only

  17. How does closing stomata affect the transpiration stream rate?

    • It increases
    • It stays constant
    • It reverses direction
    • It decreases

  18. A leaf cell has a water potential of -1200 kPa and an osmotic (solute) potential of -1500 kPa. What is its pressure potential?

    • +2700 kPa
    • -2700 kPa
    • +300 kPa
    • -300 kPa

  19. Which force primarily drives the movement of water up xylem vessels during transpiration?

    • Osmotic push
    • Transpiration pull
    • Active transport
    • Root pressure

  20. A xerophyte's stomata lose 4 mm^3 per hour per cm^2 under conditions where a normal leaf loses 10 mm^3 per hour per cm^2. What is the percentage reduction in transpiration rate per unit area?

    • 150%, since (10 - 4) / 4 x 100 equals 150
    • 42.9%, since (10 - 4) / (10 + 4) x 100 equals 42.9
    • 40%, since 4 / 10 x 100 equals 40
    • 60%, since (10 - 4) / 10 x 100 equals 60

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