In this experiment I will be testing the rate of reaction of the decomposition of Hydrogen Peroxide using the enzyme Catalase when an inhibitor is present. The inhibitor used will be Copper Sulphate.
Enzymes:.
Enzymes are biological catalysts. It increases the rate at which chemical reactions occur by lowering the activation energy. Enzymes are not altered or used up by the reactions they catalyse, so they can be used again to catalyse the reaction of another substrate molecule. Enzymes catalyse nearly every metabolic reaction that takes place in a living organism. All enzymes possess an active site, to which another molecule can bind called the substrate. The specific shape of the active site allows the substrate to fit perfectly. The combined structure of the enzyme and substrate is called the enzyme-substrate complex. Each enzyme will only act on one type of substrate molecule because the shape of the active site will only allow one shape of molecule to fit. The enzyme can either split the substrate into two or more products, or it can join to substrate molecules together. Enzymes are sensitive to temperature and pH, if these are not correct for the enzyme, the bonds that maintain the specific shape of the enzyme can be broken and so the shape of the enzyme will be denatured and can no longer bind to the substrate. Enzyme function can also be slowed down or stopped by inhibitors. The way in which enzymes work can be explained by the two following hypotheses:.
The lock and key hypothesis:.
In this hypothesis it is believed that the active sites (the lock) size, shape and chemical nature is complementary to the substrate (the key), and so each enzyme catalyses only one type of reaction. .
The induced fit hypothesis:.
This suggests that the active site in many enzymes is not exactly the same shape as the substrate, but it moulds itself around the substrate as the enzyme-substrate complex is formed.