Practise what you read: IB Biology MCQs with answers, a free test marked instantly.
Free IB Diploma Programme (DP) Biology revision notes for the 2025 syllabus, prepared by Fahad H. Ahmad and the Mega Lecture team. Notes cover Standard Level and Higher Level; HL material is flagged inside each booklet. Click any topic to open the PDF.
Theme A: Unity and Diversity
- A1.1 Water
- A1.2 Nucleic Acids
- A2.1 Origins of Cells (HL)
- A2.2 Cell Structure
- A2.3 Viruses (HL)
- A3.1 Diversity of Organisms
- A3.2 Classification and Cladistics
- A4.1 Evolution and Speciation
- A4.2 Conservation of Biodiversity
Worksheets
Theme B: Form and Function
- B1.1 Carbohydrates and Lipids
- B1.2 Proteins
- B2.1 Membranes and Membrane Transport
- B2.2 Organelles and Compartmentalization
- B2.3 Cell Specialization
- B3.1 Gas Exchange
- B3.2 Transport
- B3.3 Muscle and Motility (HL)
- B4.1 Adaptation to Environment
- B4.2 Ecological Niches
Worksheets
Theme C: Interaction and Interdependence
- C1.1 Enzymes and Metabolism
- C1.2 Cell Respiration
- C1.3 Photosynthesis
- C2.1 Chemical Signalling (HL)
- C2.2 Neural Signalling
- C3.1 Integration of Body Systems
- C3.2 Defence Against Infectious Disease
- C4.1 Populations and Communities
- C4.2 Transfers of Energy and Matter
Worksheets
Theme D: Continuity and Change
- D1.1 DNA Replication
- D1.2 Protein Synthesis
- D1.3 Mutation and Gene Editing
- D2.1 Cell and Nuclear Division
- D2.2 Gene Expression (HL)
- D2.3 Water Potential
- D3.1 Reproduction
- D3.2 Inheritance
- D3.3 Homeostasis
- D4.1 Natural Selection
- D4.2 Stability and Change
- D4.3 Climate Change
