EFFECT OF CATALASE ON HYDROGEN PEROXIDE-LAB REPORT

Effect of Catalase on Hydrogen Peroxide-Lab Report

Effect of Catalase on Hydrogen Peroxide-Lab Report

Planning (a)

Questions

The primary reaction catalyzed by catalase is the decomposition of hydrogen peroxide to form water and oxygen, which occurs spontaneously, but not at a very rapid rate. Write a balanced equation for this reaction. (Remember that catalase is not a reactant or a product and can be written over the arrow separating the reactant from the products.)

Explain why, in your first trial, you used two test tubes, one with hydrogen peroxide and one with water.

What effect did boiling the liver have on the reaction? Why?

Explain the results you obtained using a piece of muscle and a piece of potato.

What effect did acetic acid have on the reaction? Why? What effect did ammonium hydroxide have on the reaction?

Hypothesis

Catalase works best at 37ºC, and it is virtually denatured at boiling point.

Variables - chart identifying Independent, Dependent, & Controlled Variables

Variables

Units

Range

Independent Variable

Temperature

23C

15-40C

Dependent Variable

Substrate Concentration

5ml synergies

3-8ml synergies

Controlled Variables

Units

Possible effect(s) on results

Method for Control

Enzyme cofactors

Unless enzyme cofactors were present in the potato tissue containing the Catalase, they were not included in this investigation and therefore would not have affected the rate of reaction and the results of this experiment.

Coenzymes also influence the functioning of enzymes although are not bonded to the enzyme.

Planning (b)

Protocol Diagram

Photograph of Lab Setup

Procedure

Three tubes, 10mm in diameter were bored from a potato using a cork borer. Using a razor blade and a ruler, 122 discs, 1mm thick, were cut from the tubes and placed under distilled water in a petri dish. This prevented the potato from being contaminated or dehydrated.

5ml of hydrogen peroxide and 5ml of a pH 7 buffer were then measured and added to each of six boiling tubes using a syringe. Care was taken to view the syringes from the side to ensure the bottom of the meniscus was lined up properly with the gradations and there were no air bubbles in the syringe. A pH buffer was added to the boiling tubes to maintain the pH at a constant level so that changes in pH as a result of the reaction would not affect the activity of the enzyme and disrupt the results. pH 7 buffer was selected to match the natural pH of the potato tissue and therefore suit the enzyme so that it could work efficiently.

One of the boiling tubes was then connected to a manometer containing manometer fluid using a bung (see diagram below). Holding the manometer level by the bung to ensure that the fluid was at its lowest level, a mark was drawn to indicate this point using a marker pen. A further mark was then drawn 5cm above the original, measured using a ruler.

15 pieces of potato were placed in to the boiling tube using a pair of tweezers to prevent contamination. A clamp was then placed over the rubber tubing on the bung to ensure that all of the oxygen ...