This Guide supports study and revision for IBDP Chemistry Paper 3, for students planning to answer questions on Option B: Biochemistry. It reviews all SL and HL topics, summarising the essential information needed for the exam. Coverage includes: proteins and enzymes; lipids; carbohydrates; vitamins; biochemistry and the environment; nucleic acids; and biological pigments. Key features: concise definitions of key terms and concepts; worked examples to demonstrate how to solve calculations; 50 revision questions to test understanding; tip boxes to boost exam performance; and clearly presented diagrams, figures, and tables.