‹ Biology simulationsBiology · IGCSE 0610 · 5 EnzymesFour 3D simulations covering Topic 5: enzymes as catalysts, how the active site works, and the effects of temperature and pH. Explanations of kinetic energy, collisions and the enzyme-substrate complex cover the Supplement too.
A catalyst speeds up a chemical reaction and is not changed by it. Hydrogen peroxide breaks down very slowly into water and oxygen. Add a catalyst and the oxygen bubbles make the washing-up liquid foam up the cylinder. Potato cells contain the enzyme catalase.
Enzymes are proteins. Each has an active site whose shape is complementary to one substrate. The substrate fits into the active site, the reaction happens and the products leave. The enzyme is unchanged and can be used again and again.
Investigate amylase digesting starch at different temperatures. Every minute a drop of the mixture goes into iodine on a spotting tile. While starch remains it turns blue-black; when the iodine stays orange-brown, all the starch has gone. Then switch to the molecule view to see why.
| temperature / °C | time / min | rate / min⁻¹ |
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The active site's shape is held by bonds that are sensitive to pH. Away from its optimum pH the shape changes, the substrate no longer fits as well and the rate falls. Far from the optimum the enzyme is denatured. Different enzymes have different optimum pH values.
Four interactive 3D simulations for Cambridge IGCSE Biology 0610 topic 5 Enzymes: hydrogen peroxide foaming with manganese(IV) oxide, raw and boiled potato to show enzymes as biological catalysts, substrate binding to a complementary active site and the enzyme-substrate complex, the amylase and iodine spotting tile investigation of temperature with a molecule view of collisions and denaturation, and the effect of pH on the active site of pepsin, amylase and trypsin.
Four 3D simulations covering Topic 5: enzymes as catalysts, how the active site works, and the effects of temperature and pH. Explanations of kinetic energy, collisions and the enzyme-substrate complex cover the Supplement too.
Enzymes is a free, browser-based simulation for Cambridge IGCSE Biology 0610 (topic 5 Enzymes). The course is assessed in Paper 1/2 (Multiple choice), Paper 3/4 (Theory), Paper 5 (Practical Test), Paper 6 (Alternative to Practical). Syllabus for examination in 2026-2028. There are 4 tabs, each a self-contained experiment with its own controls and live readings, and nothing to install: it runs on a laptop, tablet or classroom projector.
Full syllabus map: IGCSE Biology 0610 topic 5.
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