Introduction: Living things go through chemical reactions everyday. A chemical reaction is a process in which one or more substances are chemically changed into one or more new substances. Examples of chemical reactions are as simple as typing on a key board, watching T.V., digesting food, and breathing. Breathing is a chemical reaction because humans take in oxygen which turns the glucose (sugar) into energy which humans need to survive. Enzymes can reverse a chemical reaction. For example, A+B→C. This is a general equation for the building of large molecules. C→A+B is a general equation for the breakdown of large molecules. Enzymes are reversing this chemical reaction. An enzyme is a chemical or catalyst produced by cells to speed up one specific reaction. Enzymes are found in all living things. Enzymes are necessary to all living things on Earth. The substrate is the molecule that the enzyme acts on. Think of it as a lock and key. The enzyme is the lock and the substrate is the key, so they lock together. The part of the enzyme that the substrate bonds to is the active site. The active site is basically where the substrate fits into the enzyme. Two of the many characteristics of enzymes would include that they are not used up in a reaction. That means that the enzymes never run out. Also, enzymes can only catalyze 1 type of reaction. Catalyze means to speed up. Each enzyme has a specific shape that allows it to do its job. In order for enzymes to function properly, they