AQA GCSE Computer Science (spec 8525) is the most widely-taken Computer Science GCSE in England, studied by around 80,000 students each year. The course is split across two written papers — Computer Systems and Computational Thinking — plus optional programming skills assessed through classroom work. This page brings together free revision notes, interactive tools, practice questions and tutoring support tailored specifically to the AQA 8525 specification.
All tools are completely free — no account required. They work alongside your classroom teaching and are designed around the AQA GCSE specification.
These questions are in the style of AQA GCSE exam questions. Use the hint to check your approach, then visit the Question Bank for hundreds more with mark schemes.
State what is meant by the term "cache memory" and explain why it is used.
Hint: State: small, fast memory between CPU and RAM. Explain: stores frequently used instructions/data; reduces the number of slower RAM accesses; improves overall CPU performance.
Describe the fetch stage of the fetch-decode-execute cycle.
Hint: The address in the Program Counter (PC) is copied to the Memory Address Register (MAR). The instruction at that address is fetched and placed in the Memory Data Register (MDR). The PC is then incremented to point to the next instruction.
Convert the denary number 45 to 8-bit binary. Show your working.
Hint: 45 = 32 + 8 + 4 + 1 = 00101101. Award 1 mark for correct method (repeated division or column headers), 1 mark for correct 8-bit answer.
Trace through the following bubble sort code with the list [4, 2, 7, 1, 5] and show the state of the list after each pass.
Hint: Pass 1: [2,4,1,5,7]. Pass 2: [2,1,4,5,7]. Pass 3: [1,2,4,5,7]. Pass 4: no swaps — sorted. Award 1 mark per correct pass.
Write a Python program that reads 5 integers from the user and outputs the largest value.
Hint: Use a loop to collect 5 inputs. Compare each to a "largest" variable initialised to the first input. Output the final value. Marks: loop [1], input [1], comparison logic [1], correct output [1].
Explain two threats to network security and describe a suitable defence for each.
Hint: E.g. Malware: software that damages or gains unauthorised access → install and update antivirus. Phishing: fake emails/websites trick users into giving credentials → user education and email filtering. 1 mark per threat correctly named and explained + 1 mark per appropriate defence.
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AQA does not specify a programming language in the specification. Python is by far the most common choice in schools. Questions on Paper 2 accept Python, pseudocode or any other high-level language — the mark scheme rewards correct logic, not a specific syntax.
Both Paper 1 (Computer Systems) and Paper 2 (Computational Thinking, Algorithms and Programming) are 1 hour 30 minutes each, and both are worth 80 marks — 50% of the total GCSE.
No — calculators are not permitted. All number-base conversions, file-size calculations and arithmetic must be done by hand. Practice binary, hex and denary conversions without a calculator.
The most regularly tested topics include: the fetch-decode-execute cycle, primary and secondary memory types, network topologies and protocols (TCP/IP, HTTP, DNS), types of malware and how to defend against them, and the role of the operating system.
Paper 2 most often tests: bubble sort and binary search with trace tables, Python code writing and debugging, Boolean logic and truth tables, data structures (arrays, records), and computational thinking concepts like decomposition and abstraction.
Grade boundaries change each year. Broadly, around 55–62% is needed for a grade 5, 68–72% for a grade 7, and 80%+ for a grade 9. Always check the latest published boundaries on AQA's website.