AQA As Biology Paper 2 2025 Mark Scheme Pdf

Download the official AQA AS Level Biology Paper 2 mark scheme for the June 2025 exam (7401/2). This is the final examiner-approved marking guide used during standardisation, containing full answers, detailed marking points, and examiner guidance on how marks are awarded.

The mark scheme provides complete solutions for every question in the paper. For example, Question 1 identifies key circulatory structures such as the pulmonary vein and renal artery (page 5), and explains haemoglobin adaptation with higher oxygen affinity at low partial pressures. Question 2 includes cell biology answers such as mitochondria for aerobic respiration and the roles of rough endoplasmic reticulum and Golgi apparatus in protein secretion (page 6).

Data interpretation answers are clearly explained, such as glucose uptake mechanisms (Question 2.3), where active transport is identified in the presence of oxygen and facilitated diffusion without oxygen (page 6). Calculation-based answers are also included, such as the correct ratio of 2.5:1 for glucose uptake (page 7) and stomatal density calculations with an answer of 120 stomata mm⁻² (page 9).

The mark scheme also includes practical and evaluation questions. For instance, the lipid emulsion test is described with ethanol and water producing a white emulsion (page 7), and cholesterol drug evaluation highlights statistical significance using non-overlapping standard deviation bars (page 8). Later questions cover enzyme action using the induced-fit model (page 13), plant transpiration adaptations (page 9–10), and microbiology including aseptic techniques (page 18).

Extended-response answers are fully detailed, including immunity and HIV progression (page 17), meiosis and genetic variation (page 19), and tissue fluid formation and return to the circulatory system (page 20). The mark scheme also explains key examiner principles such as error carried forward (ECF), acceptable alternative answers, and how marks are awarded consistently across responses.

This resource is essential for understanding how to gain full marks, structure precise answers, and avoid common mistakes in AS Biology exams. Fully updated for the 2025/2026 academic year and optimised for instant download on markscheme.net.

This mark scheme is essential for Year 12 students preparing for AQA AS Biology exams and Year 13 students reinforcing core A-Level Biology knowledge. It is especially valuable for students aiming for top grades by understanding exactly how examiners award marks.

Teachers and tutors use this resource to standardise marking, provide accurate feedback, and model high-quality answers. It is also ideal for independent learners and retake candidates who want detailed step-by-step solutions and insight into examiner expectations.