Group 4 · Sciences · 2025 syllabus
IB Biology
4
Units
40
Topics
150h
SL hours
240h
HL hours
Unity and diversity
19h SL · 33h HL- A1.1
Water
Unity and diversity—Molecules
- A1.2
Nucleic acids
Unity and diversity—Molecules
- A2.1
Origins of cellsHL
Unity and diversity—Cells
- A2.2
Cell structure
Unity and diversity—Cells
- A2.3
VirusesHL
Unity and diversity—Cells
- A3.1
Diversity of organisms
Unity and diversity—Organisms
- A3.2
Classification and cladisticsHL
Unity and diversity—Organisms
- A4.1
Evolution and speciation
Unity and diversity—Ecosystems
- A4.2
Conservation of biodiversity
Unity and diversity—Ecosystems
Form and function
26h SL · 39h HL- B1.1
Carbohydrates and lipids
Form and function—Molecules
- B1.2
Proteins
Form and function—Molecules
- B2.1
Membranes and membrane transport
Form and function—Cells
- B2.2
Organelles and compartmentalization
Form and function—Cells
- B2.3
Cell specialization
Form and function—Cells
- B3.1
Gas exchange
Form and function—Organisms
- B3.2
Transport
Form and function—Organisms
- B3.3
Muscle and motilityHL
Form and function—Organisms
- B4.1
Adaptation to environment
Form and function—Ecosystems
- B4.2
Ecological niches
Form and function—Ecosystems
Interaction and interdependence
31h SL · 48h HL- C1.1
Enzymes and metabolism
Interaction and interdependence—Molecules
- C1.2
Cell respiration
Interaction and interdependence—Molecules
- C1.3
Photosynthesis
Interaction and interdependence—Molecules
- C2.1
Chemical signallingHL
Interaction and interdependence—Cells
- C2.2
Neural signalling
Interaction and interdependence—Cells
- C3.1
Integration of body systems
Interaction and interdependence—Organisms
- C3.2
Defence against disease
Interaction and interdependence—Organisms
- C4.1
Populations and communities
Interaction and interdependence—Ecosystems
- C4.2
Transfers of energy and matter
Interaction and interdependence—Ecosystems
Continuity and change
34h SL · 60h HL- D1.1
DNA replication
Continuity and change—Molecules
- D1.2
Protein synthesis
Continuity and change—Molecules
- D1.3
Mutation and gene editing
Continuity and change—Molecules
- D2.1
Cell and nuclear division
Continuity and change—Cells
- D2.2
Gene expressionHL
Continuity and change—Cells
- D2.3
Water potential
Continuity and change—Cells
- D3.1
Reproduction
Continuity and change—Organisms
- D3.2
Inheritance
Continuity and change—Organisms
- D3.3
Homeostasis
Continuity and change—Organisms
- D4.1
Natural selection
Continuity and change—Ecosystems
- D4.2
Stability and change
Continuity and change—Ecosystems
- D4.3
Climate change
Continuity and change—Ecosystems
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