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Cambridge · O Level · Biology

October/November 2025 — Paper 3 · Variant 1.

5 structured questions · 9 marks

Download question paper (PDF)Mark scheme — for enrolled students

The mark scheme comes with the Biology course.

Topics covered

  • Enzyme action
  • Biological molecules
  • Effects of temperature and pH
  • Leaf structure

Questions in this paper

  • Q1a(i)Enzyme action1 marks
  • Q1b(ii)Effects of temperature and pH2 marks
  • Q1a(ii)Enzyme action1 marks
  • Q1a(vi)Enzyme action2 marks
  • Q1a(iv)Enzyme action1 marks
  • Q1a(v)Enzyme action2 marks
  • Q1a(iii)Enzyme action4 marks
  • Q1b(i)Effects of temperature and pH2 marks
  • Q2bBiological molecules2 marks
  • Q2a(iii)Anaerobic respiration4 marksincludes a figure
  • Q2a(iv)Anaerobic respiration3 marks
  • Q2cEffects of temperature and pH6 marks
  • Q2a(ii)Anaerobic respiration2 marks
  • Q2a(i)Anaerobic respiration1 marksincludes a figure
  • Q3a(ii)Leaf structure2 marks
  • Q3a(i)Leaf structure2 marksincludes a figure
  • Q3bLeaf structure3 marksincludes a figure

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