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IGCSEBiology
Trial Class

Original practice · 5 questions · 15 marks · about 17 minutes

Photosynthesis Equation and Process 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.

These questions test your understanding of photosynthesis as a chemical process, including the word and balanced symbol equations.

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 2 Both 3 marks Difficulty 2/5

    Write the word equation for photosynthesis and state where in the cell photosynthesis takes place.

    Show model answer and marking guidance
    1. Carbon dioxide + water → glucose + oxygen.
    2. Light energy is needed / absorbed by chlorophyll.
    3. Photosynthesis takes place in the chloroplasts.

  2. Question 2

    Paper 4 Extended 3 marks Difficulty 3/5

    Write the balanced symbol equation for photosynthesis.

    Show model answer and marking guidance
    1. 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂.
    2. Light energy is required (shown above the arrow).
    3. Chlorophyll is needed as a catalyst / to absorb light.

  3. Question 3

    Paper 4 Extended 4 marks Difficulty 4/5

    A student places an aquatic plant in water and counts the bubbles of gas produced per minute. The gas is collected and relights a glowing splint. Explain these observations.

    Show model answer and marking guidance
    1. The bubbles are oxygen gas produced during photosynthesis.
    2. The plant uses light energy to split water molecules and produce oxygen.
    3. Oxygen relights a glowing splint: this confirms the gas is oxygen.
    4. The bubble rate indicates the rate of photosynthesis.

  4. Question 4

    Paper 2 Core 2 marks Difficulty 1/5

    Name the two raw materials needed for photosynthesis.

    Show model answer and marking guidance
    1. Carbon dioxide.
    2. Water.

  5. Question 5

    Paper 4 Extended 3 marks Difficulty 3/5

    Explain why photosynthesis is described as an endothermic reaction.

    Show model answer and marking guidance
    1. Photosynthesis absorbs / takes in energy (from light).
    2. Energy is stored in the bonds of glucose molecules.
    3. More energy is taken in than released during the process.

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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