Lesson 3.1.1a

3.1.1a Specialised exchange surfaces and mammalian gas exchange Quiz: OCR Biology, Unit 2

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 3.1.1a, Specialised exchange surfaces and mammalian gas exchange: 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. As an organism increases in size, how does its volume change relative to its surface area?

    • Increases slower
    • Increases equally
    • Decreases faster
    • Increases faster

  2. Which feature of an exchange surface minimises the diffusion distance?

    • Good blood supply
    • Ventilation system
    • Large surface area
    • Thin barrier

  3. Root hair cells have many projections. This is an example of:

    • Increased surface area
    • Low metabolic activity
    • A thin layer
    • A good blood supply

  4. How do the thin walls of alveoli speed up gas exchange?

    • Increasing surface area
    • Maintaining concentration gradient
    • Increasing blood pressure
    • Shortening diffusion distance

  5. Why can single-celled organisms rely on simple diffusion for gas exchange?

    • High SA:V ratio
    • Thick cell wall
    • Active transport
    • Low SA:V ratio

  6. What effect does a high metabolic rate have on required gas exchange speed?

    • Thicker exchange surface
    • Faster exchange rate
    • Slower exchange rate
    • Lower oxygen demand

  7. How do you calculate surface area to volume ratio?

    • Volume ÷ surface area
    • Surface area × volume
    • Surface area ÷ volume
    • Surface area − volume

  8. A cube of side 1 cm has what surface area to volume ratio?

    • 6:1
    • 3:1
    • 1:6
    • 1:1

  9. A cube has side 3 cm. What is its surface area to volume ratio?

    • 1:2
    • 6:1
    • 2:1
    • 3:1

  10. If a cell's linear dimensions double, what happens to its surface area to volume ratio?

    • Doubles
    • Quadruples
    • Halves
    • Remains unchanged

  11. Which structures in bony fish gills provide a large surface area for gas exchange?

    • Opercula
    • Spiracles
    • Lamellae
    • Tracheoles

  12. What does countercurrent flow maintain along the entire length of the gill lamella?

    • Concentration gradient
    • High blood pressure
    • Constant temperature
    • Low water flow

  13. How does a good blood supply maintain efficient gas exchange in alveoli?

    • Decreases surface area
    • Maintains concentration gradient
    • Increases diffusion distance
    • Prevents cell lysis

  14. Which feature of root hair cells increases their efficiency of water absorption?

    • Small surface area
    • Large surface area
    • Thick cell wall
    • Impermeable membrane

  15. In countercurrent exchange, blood always meets water with what relative oxygen concentration?

    • Equal oxygen level
    • Lower oxygen level
    • Higher oxygen level
    • Zero oxygen level

  16. Why does simple diffusion through a tracheal system limit maximum insect size?

    • Long diffusion distance
    • High oxygen demand
    • Enzyme denaturation
    • Low surface area

  17. Why do large multicellular animals require specialised gas exchange systems?

    • Short diffusion distance
    • High SA:V ratio
    • Low SA:V ratio
    • Low metabolic rate

  18. A cube is scaled from side 1 cm to side 10 cm. By what factor does SA:V change?

    • 1/100
    • 100
    • 1/10
    • 10

  19. Which feature works with a thin barrier to maintain a concentration gradient in gills?

    • Small surface area
    • Thick waxy cuticle
    • Good blood supply
    • Slow water flow

  20. According to Fick's Law, diffusion rate is inversely proportional to which factor?

    • Diffusion distance
    • Temperature
    • Concentration gradient
    • Surface area

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