Required Practicals

AQA A-Level Biology includes 12 required practicals that you must carry out during your course. Although these are not assessed through coursework, questions about them appear frequently on all three exam papers. You must understand the method, variables, expected results, potential sources of error, and how to improve each practical.

Key Principle: Questions on required practicals can appear on ANY paper — not just the paper that covers the relevant topic. Paper 3 is synoptic and can include questions linking required practicals to content from any part of the specification.

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Required Practical 1: Effect of a Named Variable on the Rate of an Enzyme-Controlled Reaction

Specification link: Topic 3.1 (Biological molecules — Enzymes)

Aim

To investigate the effect of a named variable (e.g., temperature, pH, substrate concentration, or enzyme concentration) on the rate of an enzyme-controlled reaction.

Method — Example: Effect of Temperature on Catalase Activity