This AQA AS Biology exam covers a range of topics including cellular structures, biochemical processes, and genetics. Key areas include the structure of mitochondria, the differences between lactulose and lactose, and the role of ATP in muscle contraction. It also examines the biology of prokaryotic cells, DNA replication, and the effects of drugs like 6-mercaptopurine on Crohn’s disease. Additional topics include the physiological mechanisms involved in gas exchange, enzyme action, and the effects of mutations on human health. The exam emphasizes understanding biological processes, data interpretation, and applying knowledge to real-world contexts.