AQA GCSE Biology Paper 1 2025 Mark Scheme

Get the official AQA GCSE Biology Paper 1 Higher Tier (8461/1H) **June 2025 mark scheme (v1.0 Final)** — the examiner-approved document used to award marks across all **100 marks** of the exam. It includes full answers, level descriptors, and detailed marking guidance for every question.

The mark scheme begins with clear examiner instructions. On *pages 2–7*, it explains how answers are assessed, including the “best fit” approach for extended responses, how marks are awarded for calculations, and how errors carried forward (ecf) are treated.

For *Question 1 (pages 8–10)*, answers include **virus** as the pathogen for measles, transmission via droplets (e.g. coughing/sneezing), and explanation of herd immunity. The calculation question shows how to use percentages from a graph to reach **108 children** for severe infection.
*Question 2 (pages 11–13)* provides accepted answers for obesity-related diseases (e.g. type 2 diabetes), graphing requirements (correct axes, plotting, line of best fit), and enzyme activity explanations such as **amylase working at 30 °C but denaturing at 90 °C**.

For practical skills, *Question 3 (pages 14–16)* includes a full level-based mark scheme for evaluating an osmosis investigation, with indicative improvements like repeating trials, controlling variables, and calculating percentage change in mass.

Bioenergetics and plant biology are covered in *Question 4 (pages 17–19)*, including calculations of photosynthesis rate (e.g. **0.233 bubbles per second at 20 °C**) and factors affecting photosynthesis such as light intensity and carbon dioxide concentration.

Human biology answers appear in *Question 5 (pages 20–22)*, including correct identification of the **pulmonary vein**, explanation of oxygen debt, and advantages of increased red blood cells for athletes.

Later sections include diffusion definitions and gill adaptations (*Question 6, page 23*), stem cells and monoclonal antibodies (*Question 7, pages 25–27*), and microbiology including prokaryotic vs eukaryotic cells and antibiotic effectiveness (*Question 8, pages 28–30*).

This document is designed for GCSE Biology students preparing for the 2026 exam series, particularly those studying the AQA 8461 Higher Tier specification, including Year 11 students, resit candidates, and independent learners.

It is also ideal for teachers, tutors, and revision providers who need accurate mark schemes for marking mock exams, standardising grading, and teaching exam technique. It helps provide detailed feedback across all major biology topics.