Biology Internal Assessment

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How do different concentrations of enzyme affect the rate of yeast peroxidase activity? Background Information: Many organisms can demonstrate hydrogen peroxide (H₂O₂) enzymatically. Enzymes are globular proteins, responsible for most of the chemical activities of living organism (Masterman, David, and Kelly Redding). Enzymes catalyze thousands of chemical reactions that occur in living cells. In an enzyme-catalyst reaction, the substrate binds to the active site and forms an enzyme-substrate complete with the enzyme. (Heller, H. Craig., Gordon H. Orians, William K. Purves, and David Sadava).The enzyme then breaks the bonds in the structure of the substrate. The products of the reaction then leave the enzyme which remains unchanged after the reaction. The enzyme of this experiment was the yeast Peroxidase and the substrate of the experiment was hydrogen peroxide which was diluted by water. Hydrogen peroxide is toxis to most living organisms. Many organisms are capable of enzymatically destroying the hydrogen peroxide before it can do much damage. Hydrogen peroxide can be converted to oxygen and water (Masterman, David, and Kelly Redding). In the experiment, the rate of enzyme activity under various conditions such as different enzyme concentrations, pH values, and temperatures will be measured. It is possible to measure the pressure of oxygen formed in the test tube with the stopper on as the hydrogen peroxide is destroyed. After the start of the reaction, there is no product, and the pressure is the same as the atmospheric pressure. After a short time oxygen accumulates at a constant rate (Masterman, David, and Kelly Redding). Design Question: How do different concentrations of enzyme affect the rate of yeast peroxidase activity? Hypothesis: As we increase the substrate is increase, the reaction rate will increase but level off as some point as the

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