This experiment will investigate the factors that affect the rate of reaction of the enzyme catalyse, an enzyme found in food such as potato and liver. Catalyse is used to remove hydrogen peroxide from cells. The enzyme speeds up the rate of decomposition of hydrogen peroxide into water and oxygen. The reaction is:
Catalyse is able to speed up the process because the enzyme lowers the activation energy of the reaction. This means that the free energy required for the reaction to take place is made smaller by the presence of catalyse. In fact, catalyse is a particularly reactive enzyme. Biological molecules are damaged greatly by free radicals which is effectively what peroxide is. For this reason living cells evolved highly effective enzymes to decompose peroxide into harmless byproducts.
Several factors influence the effect of enzymes including concentration, pH, temperature, and the material being consumed by the reaction, called the substrate. Of interest in this reaction, is the effect of varying enzyme availability. Changing the amount of enzyme able to diffuse to the peroxide solution will cause the reaction rate to vary. One would expect the more surface area for the enzyme to leave the potato the higher the reaction rate. This hypothesis will be tested by observing the rate at which oxygen is evolved from the decomposition of hydrogen peroxide with two different sizes of potato cubes and one pureed. The same volume of potato will be used, only the geometry of the potato will be modified.
450 ml Hydrogen Peroxide
2 Erlenmeyer flasks
1 Stopper w/hole
Surgical tube (18 inches)
150mL measuring beaker
Potato (Have each potato skinned and cut into 4'x4' cubes) Stop watch
Student Instructions for experimental setup:
Organize into groups of 4 or 5 students
Obtain a full set of materials from your instructor
Take time to familiarize yourself with each piece of...