Skip to content
IGCSEBiology
Trial Class

Original practice · 5 questions · 14 marks · about 16 minutes

Cell Measurements and Magnification 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 ability to use the magnification formula and convert between units when measuring cells under the microscope.

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 2 marks Difficulty 2/5

    State the formula that relates magnification, image size, and actual size.

    Show model answer and marking guidance
    1. Magnification = image size ÷ actual size.
    2. Or: M = I / A.

  2. Question 2

    Paper 4 Both 3 marks Difficulty 3/5

    A cell has an actual length of 50 µm. It is drawn at a magnification of ×400. Calculate the length of the drawing in mm. Show your working.

    Show model answer and marking guidance
    1. Image size = magnification × actual size.
    2. Image size = 400 × 50 = 20 000 µm.
    3. 20 000 µm ÷ 1000 = 20 mm.

    Watch for: Forgetting to convert µm to mm: the answer must be in the unit requested.

  3. Question 3

    Paper 4 Extended 3 marks Difficulty 4/5

    A drawing of a cell is 60 mm long. The magnification is ×1500. Calculate the actual length of the cell in µm. Show your working.

    Show model answer and marking guidance
    1. Actual size = image size ÷ magnification.
    2. 60 mm ÷ 1500 = 0.04 mm.
    3. 0.04 mm × 1000 = 40 µm.

  4. Question 4

    Paper 2 Core 2 marks Difficulty 1/5

    Convert 0.5 mm to micrometres (µm).

    Show model answer and marking guidance
    1. 1 mm = 1000 µm.
    2. 0.5 mm = 500 µm.

  5. Question 5

    Paper 4 Extended 4 marks Difficulty 5/5

    An electron micrograph shows a mitochondrion that is 36 mm long in the image. The actual length is 2.4 µm. Calculate the magnification and explain why an electron microscope, rather than a light microscope, was needed.

    Show model answer and marking guidance
    1. Convert 36 mm to µm: 36 × 1000 = 36 000 µm.
    2. Magnification = 36 000 ÷ 2.4 = ×15 000.
    3. Electron microscope has higher resolution / can distinguish objects closer together.
    4. Internal structure of mitochondria (cristae) is too small to be seen with a light microscope.

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.

Review the related teaching