Summary IB Biology IA Enzyme Catalysis of a Potato

What is the effect of acidic substances (pH below 7) on the reaction rate of catalase with hydrogen peroxide as measured by kilopascals per second? Purpose: There are many factors that can affect enzyme catalysis, such as: temperature, pH, substrate concentration etc. Due to these many factors, the purpose of this investigation is to isolate one factor, pH, by identifying the effect of various acidic substances on the enzyme catalysis of a potato. Abstract: This investigation was conducted to deduce whether or not acidic substances have an effect on the catalysis of the enzyme catalase, located in many foods such as, livers, apples and in this case, potatoes. To test this three trials were conducted on three separate samples of Coca-Cola, distilled water, and distilled vinegar respectively. Using the LabQuests pH probe and gas pressure sensor, the pH and enzyme activity were collected of the 9 test tubes. The results were recorded, and there was an immediate indication that the distilled water had the highest reaction rate, and the distilled vinegar had a very low reaction rate. This was further illustrated after multiple charts were made, and a single way ANOVA test was completed which portrayed a clear indication that pH had an effect on enzyme catalysis. The reaction rate of the samples had a trend of increasing as pH increased, with distilled vinegar having the lowest pH of 2.89 and an average reaction rate of -.01. The Coca-Cola had a higher pH at 3.08 and an average reaction rate of 1.451. The Distilled water had the highest pH at 7 making it neutral and an average reaction rate of 2.61. This data helped to support the hypothesis drawn for this investigation. Background: Enzymes are biological molecules (proteins) that act as catalysts and help complex reactions occur everywhere in life. The enzyme which is used in this investigation is catalase, which is a common enzyme found in nearly all living organisms exposed to oxygen such as vegetable, fruits, and animals. One function of catalase is when the catalase comes into contact with hydrogen peroxide, it decomposes the hydrogen peroxide into water and oxygen. When the water and oxygen is released from the potato, substrate, and hydrogen peroxide mixture, the gas concentration is then recorded by the gas pressure sensor to measure the enzyme activity. The purpose of Varghese 3 enzymes is to catalyze (speed up) reactions, the reaction rate, is the speed/rate in which these reactions occur, which is often manipulated when enzymes are added. A substances pH is the measure of the relative amount of free hydrogen and hydroxyl ions in the water. On the pH scale there are numbers listed from 1 to 14, with those substances classified from 1 to 6 being considered acidic, and those from 8 to 14 being basic, with 7 being neutral. The solutions used in this investigation all have different pH’s ranging from as low as 3 to as high as 7. The purpose of this investigation is to depict how these solutions with varying pH level, effect the catalysis of the enzymes of a potato.