Lab Report Using a Chemical Titration to Measure Rate of Conversion of Hydrogen Peroxide to Water and Oxygen

The preparation for the experiment started by gathering the solutions of enzyme Peroxidase, substrate hydrogen peroxide, the indicator guaiacol and distilled water. Two small spectrometer tubes and three large test tubes with numbered labels. In addition, one test tube rack, one pipet pump and a box of kimwipes were also gathered. Before the experiment, the spectrometer must be set up to use by flipping the power switch to on. Following, the machine was warmed up for 10 minutes and the filter lever was moved to the left. In addition, I set the wavelength to 500 nm with the wavelength control knob. Before the experiment, I had to create the blank solution by pipetting 0.1 ml of guaiacol, 1.0 ml of turnip extract and 8.9 ml water into tube #1. Following the creation of the blank, a control 2% solution was created.

H2O2 is commonly known as hydrogen peroxide and it is a strong oxidizer and a naturally produced compound in humans as a by-product of oxidative metabolism. Because of this, humans also produce the enzyme catalase peroxidases in order to convert small amounts of H2O2 into oxygen and water. It uses the following chemical formula:

The topic of this lab is on biochemistry.This experiment was conducted to show how cells prevent the build of hydrogen peroxide in tissues. My group consisted of Lekha, Ruth, and Jason. There were used two different concentrations of hydrogen peroxide through this experiment , 1.5% and 3%. By testing two different types it is easier to understand how the H2O2 and catalase react with one another. To do this both the yeast, which was our catalase, and H2O2 were mixed together in a beaker. Each concentration was tested out twice for more accurate results . 1.5% concentrated H2O2 had an average reaction rate of 10.5 seconds while 3% concentrated H2O2 had an average reaction rate of 7.5 seconds. From this experiment we learned that by increasing the concentration of H2O2 and chemically combining it with a catalase it will speed up the reaction. Enzymes speed up chemical reactions . The independent variable in this experiment was the concentration of the H2O2. Some key vocabulary words are Catalase, enzyme, hydrogen peroxide ( H2O2), and concentration.

Enzyme catalysis is dependant upon factors such as concentration of enzyme and substrate, temperature and pH. These factors determine the rate of reaction, and an increase in temperature or pH above the optimum will

This investigation will be carried out to investigate the rate of reaction of the enzyme catalase on the substrate hydrogen peroxide.

The purpose of this experiment was to simply measure oxygen production rates released from decomposed hydrogen peroxide under different conditions (concentration of enzymes, temperature, and PH level).

Question: How does changing enzyme concentration or temperature affect the reaction time of enzyme activity?

1. We measured 2 mL of diluted hydrogen peroxide (the substrate), 1 mL of guaiacol (the product indicator), and 1 mL of neutral buffer (pH 7) with a syringe and disposed it into tubes 1, 2 , 4, 9, 11, and 12.

There were three test tubes in which the experiment was held. A relatively equal sized portion of raw potato (this contained the enzyme [a biological catalyst] hydrogen peroxidase) was placed in each tube. Then, enough water to cover the potato was added. Proceeding this, each of the test tubes were assigned a temperature; cold, room temperature or warm (this was written on the tag so that they were not confused). The test tube destinated ‘cold’ was placed in a ice bath for five minutes. At the same time, the ‘hot’ test tube was placed in a hot water bath for five minutes. Meanwhile, the room temperature test tube sat at room temperature for five minutes. When the five minutes were over, the test tubes were returned to the rack (so that they were able to be observed). Then, the test tubes were allowed to sit at room temperature for five more minutes. Once that period of time was over, 2 ml of hydrogen peroxide (the substrate) was added to each tube.

Recognizing the error is important, and only a few errors were found in this experiment. One example for these trials could be that the coffee filters weren’t exactly 3 x 3 centimeters. This is an error because the filter could pick up more solution and affect the speed that it would sink and rise. Also, with each baby food jar used, two coffee filters were dipped in it. If more coffee filters were dipped in the hydrogen peroxide, then more solution could be in the hydrogen peroxide affecting the times. It would affect the times because more solution molecules would be in the hydrogen peroxide and would collide with the new molecules on the coffee filter making the reaction time faster. Lastly the data would be more accurate if the amount of catalase solution on the coffee filter should be more controlled. This could happen by stirring the solution before and after the filter is put in, and holding the filter exactly five

Peroxidase is an enzyme found in potatoes that catalyzes the breakdown of hydrogen peroxide, H2O2, into O2 gas and water. We examined the different pH environments that can affect the enzyme activity during the breakdown of H2O2. In order to do this, we added different levels of pH, low, medium, and high, into different test tubes with the enzyme and H2O2, and we then inverted the tube. The amount of O2 gas produced was then measured and recorded. The result was that the higher pH produced more gas, followed by medium pH, then low pH. The enzymes were more active in the pH of about 10. It increased

Lab Report Lesson 1 – Plan Your Experiment Aim: How does changing the mass of liver placed inside hydrogen peroxide affect the amount of oxygen formed? Identify factors, which affect: ______the amount of oxygen formed_______. Hypothesis: If the mass of liver increases when put in to the same amount of Hydrogen Peroxide, then more oxygen will be produced in the same amount of time.

The purpose of this investigation is to discover the effect of pH on the activity of catalase, an enzyme which plays the integral role of converting hydrogen peroxide into water and oxygen, and discover which pH level it will work at the most efficient rate (the optimum). The original hypothesis states that that the optimum would be at a pH is 7, due to the liver, where catalase usually resides, being neutral. The experiment consists of introducing the catalase to hydrogen peroxide, after exposure to certain solutions; hydrogen peroxide, water and hydrochloric acids, all containing the adjusted pH, and measuring the height of froth formed, an observable representation of the activity of the enzyme. The final data indicated that

The chemical hydrogen peroxide(H₂O₂) is broken down by the enzyme catalase. Hydrogen peroxide is a byproduct formed in cellular reactions that, if not broken down, could inflict severe damage to the cell. Catalase is an enzyme that breaks down hydrogen peroxide in to water and oxygen. How efficient and strong the enzymes reaction to break down H₂O₂ determines largely on temperature and pH level. An enzyme only functions within a set pH and temperature range. Beyond that it becomes denatured, rendering it useless. The purpose of this lab is to determine at which temperature and pH level the enzyme catalase reacts best. Catalase in chicken and beef livers will be used to do the lab because enzymes still function after death as long as they are kept refrigerated at a low temperature.

The Hypothesis was proven partially correct by the experiment. As the hypothesis stated, when the temperature was increased, the efficiency of the catalysed reaction decreased. This was due to the denaturing of the active site of the protein. However,