Unit 3 summary

This clear and high-yield study pack provides a comprehensive summary of AQA A-Level Biology Unit 3 (Organisms exchange substances with their environment). Written strictly to align with the latest AQA specification, these notes condense complex pathways and transport mechanics into easily digestible, exam-focused breakdowns designed to help you secure an A grade*. The resource covers every core subsection in maximum detail: surface area to volume ratios, gas exchange across different organisms (insects, fish, humans, and plants), digestion and nutrient absorption in the ileum, and mass transport systems (including the cardiac cycle, haemoglobin dissociation curves, and plant transport via xylem and phloem). Packed with precise terminology required by examiners, essential mathematical formulas (like pulmonary ventilation), and step-by-step required practical summaries, this document is the ultimate plug-and-play revision tool for mastering your Paper 1 and Paper 3 exams.