H2 Biology Amylase Practical: Starch, Iodine and Endpoint Evidence

An amylase investigation can follow starch disappearance by testing small samples with iodine. The useful observation is when a sample stops giving a blue-black starch test. This is an endpoint measurement, not a continuous record of product formation.

Use this guide to understand and plan a supervised investigation. The teacher supplies the enzyme preparation, reagent concentrations, working volumes and permitted conditions. Follow that protocol rather than treating an online example as a recipe. Read Lab safety starts before the experiment for preparation and supervision expectations.

Match the investigation to its question

The 2026 SEAB H2 Biology syllabus, 9477, page 13, outcome 1(q), includes investigating temperature, pH, enzyme concentration and substrate concentration. It gives substrate disappearance using amylase, starch and iodine as an example, alongside product formation using catalase. These methods provide different kinds of evidence.

Choose one independent variable for each investigation. State what you measure, how you recognise the endpoint and what remains constant. There is no single pH or temperature optimum to assume for all enzyme preparations.

Understand the sampling method

The