IB Biology · current syllabus

IB Biology lessons

Every lesson in the course, from A1.1 Water to D4.3 Climate change. Each page has a one-page summary, the key terms, sample exam questions with answers, and free illustrated revision slides. Lessons marked HL are for Higher Level only.

Theme A: Unity and diversity

A1.1Water
A1.2Nucleic acids
A2.1Origins of cells HL
A2.2Cell structure
A2.3Viruses HL
A3.1Diversity of organisms
A3.2Classification and cladistics HL
A4.1Evolution and speciation
A4.2Conservation of biodiversity

Theme B: Form and function

B1.1Carbohydrates and lipids
B1.2Proteins
B2.1Membranes and membrane transport
B2.2Organelles and compartmentalisation
B2.3Cell specialization
B3.1Gas exchange
B3.2Transport
B3.3Muscle and motility HL
B4.1Adaptation to environment
B4.2Ecological niches

Theme C: Interaction and interdependence

C1.1Enzymes and metabolism
C1.2Cell respiration
C1.3Photosynthesis
C2.1Chemical signalling HL
C2.2Neural signalling
C3.1Integration of body systems
C3.2Defence against disease
C4.1Populations and communities
C4.2Transfers of energy and matter

Theme D: Continuity and change

D1.1DNA replication
D1.2Protein synthesis
D1.3Mutation and gene editing
D2.1Cell and nuclear division
D2.2Gene expression HL
D2.3Water potential
D3.1Reproduction
D3.2Inheritance
D3.3Homeostasis
D4.1Natural selection
D4.2Stability and change
D4.3Climate change