IB Biology Revision Guide
Everything you need to revise for IB Biology — the four themes broken down, a revision timetable, exam tips for Paper 1 (Section A and B) and Paper 2, and AI-powered study tools. SL & HL.
IB Biology Topics to Revise
Theme 1 — Unity and diversity
Water and biological molecules, cell structure, viruses, classification, and the evidence for evolution.
Theme 2 — Form and function
Membranes and transport, enzymes and metabolism, gas exchange, transport systems, and muscle and movement.
Theme 3 — Interaction and interdependence
Cell signalling, the nervous and endocrine systems, homeostasis, ecosystems, and the carbon and nitrogen cycles.
Theme 4 — Continuity and change
DNA replication, protein synthesis, cell division, inheritance, gene expression, and natural selection.
Biology Revision Timetable (10 Weeks)
Week 1–2Theme 1: molecules, cells, viruses, classification, evolution
Week 3–4Theme 2: membranes, enzymes, gas exchange, transport
Week 5–6Theme 3: signalling, homeostasis, ecosystems, nutrient cycles
Week 7–8Theme 4: replication, protein synthesis, inheritance, selection
Week 9–10Past papers (Paper 1 Section A & B and Paper 2) and weak-topic review
Top Biology Revision Tips
- Answer to the command term — "outline" stays brief, "explain" needs reasons, and "discuss"/"evaluate" need a balanced judgement.
- Make one distinct biological point per mark — examiners tick discrete marking points, so short and separate beats one long sentence.
- Use precise terminology: "active transport", "denatured", "semi-conservative" — the marking point usually needs the exact word.
- In Section B data questions, describe the trend and quote figures with units before explaining the biology.
- Practise the key drawings (cell, neuron, nephron, heart, DNA) and label every structure precisely.
- There is no data booklet — memorise the few calculations you need (magnification, percentage change, Hardy–Weinberg at HL).