Methodology

This list is based on analysis of Pearson Edexcel IGCSE Biology 4BI1 past papers (2019–2024), examiner reports, mark schemes and topical question banks. SaveMyExams data shows Structure & Function has 134+ questions (22 hours)—the most heavily tested area.

Top 10 most frequently tested topics

1. Structure and function in living organisms

Evidence: Most heavily tested section (22 hours, 134 questions in topical banks). Cell structure, organisation, biological molecules.

Covers: cell structure; tissues; organs; biological molecules; movement of substances.

2. Nutrition and digestion

Evidence: Substantial question bank. Examiner reports note energy in food chains and excretion errors.

Covers: diet; digestion; enzymes; absorption; balanced diet.

3. Respiration and gas exchange

Evidence: Core to papers. Linked to respiration and gas exchange systems.

Covers: aerobic and anaerobic respiration; gas exchange in humans; lungs.

4. Transport systems

Evidence: Blood, circulation, heart. Part of Structure & Function.

Covers: circulatory system; blood; heart; transport in plants.

5. Coordination and response

Evidence: Nervous system, hormones, homeostasis. Examiner reports note command word (describe vs explain) errors.

Covers: nervous system; reflex arc; hormones; homeostasis.

6. Reproduction and inheritance

Evidence: 6 hours, 32 questions (Unit 2 modular). Examiner reports note inheritance and variation.

Covers: reproduction; inheritance; genetics; variation.

7. Ecology and environment

Evidence: Food chains, ecosystems, human impact. Examiner reports note energy “lost” vs “transferred” errors.

Covers: food chains; ecosystems; human impact; conservation.

8. Enzymes

Evidence: Enzyme action, temperature, pH. Examiner reports highlight enzyme-related confusion.

Covers: enzyme action; effect of temperature and pH; lock-and-key.

9. Cell structure and organisation

Evidence: Cell structure, magnification. Examiner reports note precision in terminology (e.g. lymphocytes).

Covers: cell structure; magnification; organelles; organisation.

10. Excretion and homeostasis

Evidence: Kidney, excretion. Examiner reports note excretion vs indigestible parts confusion.

Covers: kidney; excretion; homeostasis; osmoregulation.

Revision priority

Structure and Function (cells, transport, nutrition, respiration) carries the most marks. Focus on describe vs explain and precise terminology. See common mistakes.

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Sources: Edexcel past papers 2019–2024, examiner reports, SaveMyExams specification analysis.