Investigating the functioning of a biological catalyst: catalaseThe topic under investigation was the functioning of a biological catalyst. An enzyme is a protein that acts as a biological catalyst for chemical reactions and is capable of accelerating them. The shape of each enzyme is very precise and this gives the enzyme the ability to catalyze a specific reaction. Enzymes have a three-dimensional shape, which is essential for their functioning. In every enzyme there is a region called the active site where a complementary substrate molecule binds. Next, the enzyme is ready to bind to other molecules and the process repeats. However, enzymes require certain conditions to function effectively. Temperature, pH, and substrate concentration all influence enzyme activity. Catalase is a specific type of enzyme and is found in almost all living organisms exposed to oxygen. Catalase is found for example in the liver where it breaks down hydrogen peroxide into water and oxygen. When this reaction occurs, bubbles of oxygen gas escape and create foam. In test tube 1 there were 4 ml of water and a cube of liver. Catalase did not break down hydrogen peroxide when the liver was immersed in water. Oxygen gas bubbles were created, but the solution did not foam. Enzyme activity was not affected since the pH of water, which is 7, is similar to the pH maintained by the liver. In test tube 5 a cube of boiled liver was placed in hydrogen peroxide. The boiling liver made irreversible changes to the structure of catalase and it could no longer function properly, it became denatured. Boiling the liver damaged the catalase enzyme and clearly decreased the amount of bubbles when exposed to hydrogen peroxide; no foam was created. ...... middle of paper ...... perfect. This is shown in Figure 3. Figure 3 The effect of substrate concentration on enzyme activity (http://alevelnotes.com/content_images/i73_Image3.gif) In conclusion, catalase being an enzyme, requires specific conditions to function properly better efficiency. Temperature, pH, and substrate concentration are all factors that influence enzyme activity, and if these are altered, enzyme activity will increase or decrease. Catalase is an enzyme found in the liver that breaks down hydrogen peroxide into water and oxygen. This creates bubbles of oxygen gas that escape and create foam. When any of the three factors above are altered, catalase activity is affected and there will be more foam, less foam, or no foam at all. This is because they all affect the rate at which enzymes operate and produce their products.