Lock And Key - GCSE Biology Definition

The "Lock and Key" model in GCSE Biology describes how enzymes work in the body. Enzymes are special proteins that speed up chemical reactions. Each enzyme has a unique shape with a specific area called the active site. This is like a lock. The substrate, which is the substance that the enzyme works on, fits perfectly into this active site, like a key. When the substrate fits into the enzyme, the reaction can happen more quickly and efficiently. This model helps explain why enzymes are so specific and only work with certain substances.