This AQA AS Biology exam covers various topics in molecular biology, genetics, physiology, and cell biology. Key subjects include DNA structure, gene replication, the roles of organelles in protein synthesis, and enzyme action. The paper explores the replication process of HIV, including the role of antigens and antibodies, and addresses biological mechanisms such as osmosis in chicken eggs. It also investigates the function of erythropoietin (EPO), the use of monoclonal antibodies in drug testing, and the physiological effects of synthetic EPO. The exam further evaluates understanding of cell structure, organelle function, and biological applications.