Rates of Reaction

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Rates of Reaction Affected By Concentrations of a Substrate.

Darian Naill
September 19, 2011
Swanson
AP Biology
Introduction
An enzyme is a protein molecule that helps other organic molecules start chemical reactions with one another; however, the enzyme itself is not affected by the reaction. A substrate is the substance acted upon by the enzyme. In this lab, catalase is the enzyme and hydrogen peroxide is the substrate. Catalase is found in both plant and animal tissues, and is abundant in plant storage organs. In this experiment, catalase is used from potatoes. Catalase is important to living things because it prevents the accumulation of hydrogen peroxide in the cell. Hydrogen peroxide is produced naturally as a byproduct of metabolism. It tends to disrupt the cells’ chemistry, too much can kill a cell. Therefore, the presence of catalase is needed to survive. Catalase breaks down the toxic hydrogen peroxide into harmless water and oxygen. If the concentration of the substrate hydrogen peroxide is related to the reaction rate of the enzyme catalase, then an increase in the concentration of hydrogen peroxide will increase the reaction rate of catalase. Catalase:

Methods and Materials
In order to experiment and determine the affects concentration has on reaction rate, you will need several materials. Such as, potato extract, crushed ice and water in a large beaker to keep the catalase cool, since catalase is sensitive to temperature. Hydrogen peroxide solution is needed at six different concentrations (10%, 25%, 40%, 60%, 75%, and 100%). Also, 0% hydrogen peroxide is needed, which is just simply water. In addition, you will need a 10 ml graduated cylinder, a 50 ml beaker, forceps, paper dots (Whatman #1 filter paper, 1 cm diameter), a paper towel, a stopwatch, and graph paper. During this lab, be careful of the hydrogen peroxide because it can damage skin and clothes. Be sure to immediately rinse and spills with water. Throughout the lab, always...
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