Explain the lock and key hypothesis of chemical reactions.

The lock and key hypothesis explains how each enzyme acts specifically on a certain substrate. The lock is the enzyme. The key is the substrate. The lock has a site where a specific substrate binds called the active site. The active site only fits the substrate that is specific to the substrate. When the substrate binds to the enzyme's active site, under the correct conditions such as temperature and pH), an enzyme-substrate complex forms. The product will be formed and is released from the complex. The enzyme remains unchanged through this process.