bio letters

IB biology notes

LAST UPDATED: 16^th February, 2026
11 topic notes left to go
topic notes should be done before May 2026 exams

Question Bank

A4.1 Paper 1A

C4.1 Paper 1A

C4.2 Paper 1A

C4.2 Paper 2

Notes

A1.2 Nucleic acids

A2.2 Cell Structure

NEW

A4.1 Evolution and speciation

A4.2 Conservation of biodiversity

B1.1 Carbohydrates and lipids

B2.2 Organelles and compartmentalization

B2.3 Cell specialization

B3.3 Muscle and motility

B4.1 Adaptation to environment

B4.2 Ecological niches

C1.1 Enzymes and metabolism

C1.2 Cell respiration

C1.3 Photosynthesis

C2.1 Chemical signalling

C2.2 Neural signalling

C3.1 Integration of body systems

C3.2 Defence against disease

C4.1 Populations and communities

C4.2 Transfer of energy and matter

D1.1 DNA replication

D1.2 Protein synthesis

D1.3 Mutation and gene editing

D2.2 Gene expression

D3.1 Reproduction

D3.2 Inheritance

D3.3 Homeostasis

D4.1 Natural selection