Enzymes - GCSE Biology Definition

Enzymes are special proteins that act like tiny machines inside living things, helping to speed up chemical reactions. They are essential for many processes in the body, such as digestion, where they break down large food molecules into smaller ones that can be easily absorbed by the body. Each enzyme is specific, meaning it only works on a certain type of molecule, much like a key that only fits a specific lock. This specificity ensures that reactions occur quickly and efficiently at body temperature. Without enzymes, many important reactions would happen too slowly to keep us alive.