This AQA AS Biology exam focuses on cellular processes, biochemistry, genetics, and ecological interactions. Key topics include enzyme function in protein digestion, the impact of diet on protein absorption in rabbits, and the relationship between carbon dioxide concentration and oxyhaemoglobin dissociation. The paper also explores physiological adaptations of seals for diving and investigates the structure and function of DNA. Students analyze the effects of vaccine injections on immune response, including the role of memory B cells. The exam further covers topics like the movement of substances across membranes, genetic diversity, and the application of statistical tests in biological research.