OCR GCSE Computer Science Complete Practice Exam 2025

The Central Processing Unit (CPU) is the component responsible for processing all the data and instructions that enable a computer system to function. The CPU executes instructions from programs and manages the operations of other components within the computer, making it the "brain" of the system.

When a program runs, the CPU retrieves instructions from memory, decodes them, and then executes them, which involves performing calculations, moving data around, and making decisions based on the data it processes. This central role is essential because without the CPU, the computer would not be able to perform any tasks or run applications.

In contrast, the memory unit stores data and instructions temporarily so that they can be accessed quickly by the CPU, while the Graphics Processing Unit (GPU) is specialized for rendering images and handling graphics computations, rather than general data processing. Input/output devices serve as interfaces for users to interact with the computer and do not process data in the same way the CPU does.