Chemical reactions are relied on several factors to improve their reaction speed, one of which is enzymes. Enzymes are used in multiple areas of life, within your body and within engineering disciplines, such as genetic engineering and protein engineering. So what are enzymes? Enzymes are biological catalysts. Catalyst speed up the rate of reaction without being used up. Living things create enzymes to reduce the need for high temperatures to increase rate reaction, and they only use the important reactions in your body. Enzymes are made up of proteins which are chains of amino acids, and these are fold-in specific shapes. The specific shape allows them to catalyze reactions. Enzymes are the special area in their structure-coordinate active site that allows the enzyme to fit onto the reactants, if it's substance other than the reactants attempts to join the enzyme it will not fit, and the reaction will not catalyze. Enzymes normally only catalyze one reaction. The following steps occur during a reaction. The reactants also call the substrate enter the active site of the enzyme, and enzyme substrate complex is formed, and the reaction takes place. The enzyme is used as a medium to lower the activation energy, and the products exit the active site and the enzyme remains unchanged. Enzymes have an optimal temperature they work best in. High temperatures benefit the enzyme as it means more collisions are occurring, but too high temperature in the enzyme the active site changes, and it becomes denatured. In our body, 37 degrees is the optimal temperature for enzymes. Enzymes also have an optimal pH range, too high or too low causes. Enzymes to become denatured as the active site changes. Different enzymes have different pH range, such as pepsin, which has a pH range of two, and amylase, which has an optimal pH range of seven.