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IGCSEBiology
Trial Class

Original practice · 5 questions · 16 marks · about 18 minutes

Leaf Structure and Adaptation Practice Questions

Biology editorial review is supported by the named review panel. Reviewer participation may vary by guide. Checked against Cambridge IGCSE Biology 0610 (2026–2028); last reviewed August 2026.

Test your knowledge of how the internal structure of a leaf is adapted for efficient photosynthesis and gas exchange.

Before you open the answers

  • Attempt every question without notes.
  • Show working for calculations and write complete biological statements.
  • Use the suggested time as a guide, not a strict limit on the first attempt.

These are original practice questions. They do not reproduce an official Cambridge paper or official mark scheme.

  1. Question 1

    Paper 4 Both 4 marks Difficulty 3/5

    Describe four features of a leaf that make it well adapted for photosynthesis.

    Show model answer and marking guidance
    1. Broad and flat: large surface area to absorb maximum light.
    2. Thin: short diffusion distance for gases (CO₂ in, O₂ out).
    3. Palisade layer packed with chloroplasts: positioned near upper surface for maximum light absorption.
    4. Stomata allow CO₂ to enter and O₂ to leave the leaf.

  2. Question 2

    Paper 4 Both 3 marks Difficulty 3/5

    Explain the role of the spongy mesophyll layer in the leaf.

    Show model answer and marking guidance
    1. Cells are loosely packed with air spaces between them.
    2. Air spaces allow gases (CO₂ and O₂) to diffuse through the leaf.
    3. Moist cell surfaces allow gases to dissolve before entering/leaving cells.

  3. Question 3

    Paper 4 Extended 3 marks Difficulty 3/5

    Explain how guard cells control the opening and closing of stomata.

    Show model answer and marking guidance
    1. Guard cells take up water by osmosis and become turgid: stoma opens.
    2. Guard cells lose water and become flaccid: stoma closes.
    3. The inner wall of each guard cell is thicker, so when turgid the cell bends, creating an opening.

  4. Question 4

    Paper 2 Core 2 marks Difficulty 1/5

    Name the green pigment in leaves that absorbs light for photosynthesis.

    Show model answer and marking guidance
    1. Chlorophyll.
    2. Found inside chloroplasts.

  5. Question 5

    Paper 4 Extended 4 marks Difficulty 4/5

    Most stomata are found on the lower surface of the leaf. Suggest why this is advantageous for the plant.

    Show model answer and marking guidance
    1. Lower surface receives less direct sunlight: reduces water loss by evaporation.
    2. Reduces the rate of transpiration through the stomata.
    3. Upper surface absorbs more light for photosynthesis.
    4. Keeps the temperature of the stoma region lower, reducing water vapour loss.

Mark the set consistently

Award a point only when the idea is clearly present in the written answer. Correct any missed point in a complete sentence, then test the same skill on a different question several days later.

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