Introduction to A2 Biology; Specification Map; Unit 3: Chemical elements and biological compounds, Cell structure and organisation, Cell membranes and transport, Biological reactions are regulated by enzymes, Nucleic acids and their function, Cell cycle and cell division; Component 2: Organisms and evolutionary history, Adaptations for gas exchange, Adaptations for transport in animals, Adaptations for transport in plants, Adaptations for nutrition; Exam practice questions