Enzymes are a type of biological molecule which increase the rate of all chemical reactions occur in the cells. Enzyme has an amazing role of speeding up a metabolic reaction in a cell without itself being altered by the reaction. It accelerates the speed of the reaction. They act as highly specific catalyst and provide a mechanism whereby individual chemical reactions can be controlled. Although some enzymes are excreted out of the cell but most of the all enzymes are initially produced used in a cell and function in the cell’s environment. There are two types of enzymes which are intracellular enzyme and extracellular enzyme. In this experiment, we are using catalase which is intracellular enzyme. Intracellular enzyme is also known as endoenzyme. Moreover, the molecules that enzyme react with are called as substrates. In case to increase the reaction of chemical reactions in cell, substrate will then bind to the enzymes on a region called active site of the cell.