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IGCSEBiology
Trial Class

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

Carbohydrates and Lipids 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 cover the structure, function, and testing of carbohydrates and lipids as required by the IGCSE Biology 0610 syllabus.

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

    State the elements found in carbohydrates and give one example of a simple sugar and one example of a complex carbohydrate.

    Show model answer and marking guidance
    1. Carbohydrates contain carbon, hydrogen, and oxygen.
    2. Simple sugar: glucose (or fructose / maltose).
    3. Complex carbohydrate: starch (or glycogen / cellulose).

  2. Question 2

    Paper 4 Extended 3 marks Difficulty 3/5

    Explain why lipids are a better long-term energy store than carbohydrates.

    Show model answer and marking guidance
    1. Lipids contain more energy per gram than carbohydrates.
    2. Lipids are insoluble in water: they do not affect water potential / osmosis in cells.
    3. Lipids are more compact / lighter for the same amount of stored energy.

    Watch for: Simply saying "lipids have more energy" without comparing to carbohydrates per unit mass.

  3. Question 3

    Paper 4 Both 4 marks Difficulty 3/5

    Describe the test for lipids (fats and oils) and state the expected result.

    Show model answer and marking guidance
    1. Add ethanol to the food sample and shake to dissolve any fat.
    2. Pour the ethanol solution into a test tube of water.
    3. A white/cloudy emulsion forms if lipid is present.
    4. This is called the emulsion test.

  4. Question 4

    Paper 2 Core 2 marks Difficulty 1/5

    State two functions of carbohydrates in organisms.

    Show model answer and marking guidance
    1. Source of energy (glucose used in respiration).
    2. Structural role (cellulose in plant cell walls).

  5. Question 5

    Paper 4 Extended 3 marks Difficulty 4/5

    Starch, glycogen, and cellulose are all polymers of glucose. Explain why they have different properties despite being made from the same monomer.

    Show model answer and marking guidance
    1. They have different arrangements / bonding between glucose molecules.
    2. Starch is a mixture of amylose (unbranched) and amylopectin (branched): good for compact energy storage in plants.
    3. Glycogen is highly branched: can be rapidly broken down for quick energy release in animals.
    4. Cellulose has straight chains with cross-links forming strong fibres: structural support in cell walls.

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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