The purpose of this simulation is to visually model how enzymes work and the main factors that affect their activity. There are two main modes: Basic which introduces the two main models of enzyme action and Advanced mode which allows you to systematically investigate the effects of temperature, pH, substrate concentration, competitive inhibitors and non-competitive inhibitors. Note: The aim of this sim is not to produce perfect mathematical models of enzyme action, but to provide a visual physical model, from which largely realistic behaviours emerge, so that students can internalise the key principles involved.