AQA As Computer Science Paper 2 2025 Mark Scheme

Get the official AQA AS Computer Science Paper 2 mark scheme from the June 2025 series (7516/2), version 1.0 Final. This is the exact examiner-approved document used during marking and standardisation to ensure consistent grading across all candidates.

The mark scheme provides detailed answers, indicative content, and marking guidance for every question in the Paper 2 exam. Early sections include number systems and binary arithmetic (page 7), such as byte capacity (256 values), binary addition with carry, and two’s complement ranges (−8 to 7). It also includes worked solutions for fixed-point representation (page 8) and ASCII encoding (page 9), alongside explanations of Unicode limitations.

Further sections cover sound sampling and DAC roles (page 10), data compression using run-length encoding (page 11), and low-level programming concepts including hardware vs software, system vs application software, and assembler roles (pages 12–13). The mark scheme also details logic circuits and parity bit calculations (page 14), including XOR gate behaviour and even parity detection.

Advanced topics include Boolean algebra (De Morgan’s law and logic circuit construction, page 16), the Fetch-Execute cycle with MAR, MBR, and CIR roles (page 17), and assembly language programming (page 18), including full solutions for calculating triangular numbers using loops and register manipulation.

The document also includes level-of-response marking criteria for the 9-mark evaluation question (page 20), covering moral, ethical, legal, and cultural issues such as data privacy, GDPR, copyright law, and societal implications of image-sharing platforms.

Use this mark scheme to understand exactly how marks are awarded, identify common mistakes (e.g. incorrect binary subtraction, misunderstanding parity logic), and improve exam technique for the 2026 exam. Best used alongside the AQA 7516/2 May 2025 question paper.

This document is for AS Computer Science students preparing for the 2026 exam series, including Year 12 students and those building strong theoretical understanding for A-Level progression.

It is also essential for teachers and tutors who require accurate, examiner-aligned marking guidance for mock exams, classroom assessment, and structured revision sessions using real exam materials.