AQA A Level Biology Paper 3 2025 Mark Scheme Pdf

Download the official AQA A-Level Biology Paper 3 mark scheme for the June 2025 exam (7402/3). This is the final examiner-approved marking guide used during standardisation, containing full answers, detailed marking points, and level-of-response criteria for the essay section.

The mark scheme provides complete solutions for Section A, including structured answers and calculation guidance. For example, Question 1 includes key marking points for binary fission such as DNA replication and cytokinesis (page 5), while Question 1.2 provides the correct percentage increase calculation (1159%) with method marks for working (page 6). Question 3 includes a full mark–release–recapture calculation with the correct population estimate of 1215 beetles (page 11), and Question 6 includes the spirometry calculation with an answer of approximately 5.35 dm³ (page 18).

It also includes detailed biological explanations for extended-response questions, such as ATP synthase inhibition (page 7), kidney function and nephron processes (page 8), immune response evaluation (page 14), and genetic methylation analysis (page 16). Each question includes examiner commentary on acceptable answers, common errors, and alternative valid responses.

Section B essay marking is explained using AQA’s level-of-response system (pages 21–23), with clear criteria for levels ranging from basic (1–5 marks) to extended abstract (21–25 marks). The mark scheme outlines how to achieve top-level answers by linking multiple topics, using precise biological terminology, and demonstrating synoptic understanding.

This resource is essential for understanding how marks are awarded, how to structure high-level answers, and how to maximise marks in both data-analysis and essay questions. Fully updated for the 2025/2026 academic year and optimised for instant download on markscheme.net.

This mark scheme is essential for Year 13 students preparing for the 2026 AQA A-Level Biology exams who want to master Paper 3, including synoptic questions, practical application, and essay writing. It is particularly useful when used alongside the Paper 3 question paper for full exam practice.

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