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Discuss An Enzyme Catalysed Reaction With An Example Of A Persuasive Essay

Hydrogen peroxide has an acidic pH which will break down into water which has a neutral pH. This may effect the enzyme action as many enzymes work faster in a neutral environment, the only control over this is the fact that it will happen in each test and to consider its effect at the end of the experiment. I will need to use the same potato and cut a fresh chip at each stage of the experiment as the catalase may become effected by exposure to the air. This may effect results so I will keep the chips as similar as possible. The apparatus should have been washed with distilled water and I will use a different conical flask for each test so that any reactants left in a flask wont affect further tests. The procedure will stay the same so that the results can be compared.

Apparatus list and setup:

- Potato

- Potato borer

- Ruler

- Scalpel

- 6 conical flasks

- 20ml syringe (to hold enough hydrogen peroxide to cover the chip in the boiling tube)

- Double holed bung

- Retort stand

- Clamp

- Tongs

- Goggles

- 50ml glass measuring cylinder (to measure gas produced accurately and allow space for the displaced gas.

As the cylinder is larger than necessary I can take the next reading directly after the first without having to fill the cylinder as much)

- Bowl of water

- Hydrogen peroxide 20vol

- Splint

- Timer

- Delivery tube

- Tile



1. Set up apparatus including filling glass cylinder with water and placing it upside down in water, measure width of potato borer and apply this to surface area formula

2. Read the level the glass measuring cylinder shows

3. Cut a piece of potato 4cm...

Essay about Potato Catalase Lab

736 WordsSep 20th, 20123 Pages

Grade 12 Biology (SBI 4U1) Nicole Mikulis
Unit: Biochemistry Sept 14 2012
Lab: Effect of temperature and pH on catalase activity


Catalase is an enzyme that detoxifies chemicals that might harm the cell such as hydrogen peroxide (H2O2). The enzyme breaks H2O2 into water and oxygen. The production of the oxygen gas bubbles serves as evidence that the catalase enzyme is working. As catalase is breaking the bonds between H2O2, it is releasing energy in the form of heat which is reason for the warmth of the bubbles during the reaction. Starch acts to trap these bubbles and this creates a relatively stable foam that can be measured.


1. a) Describe the effect of…show more content…

At lower temperatures, there is less catalase activity in the test tubes.

b) Explain these observations based on the theory molecular motion. Because of the lower temperature, there is less molecular motion which decreases the number of collisions happening between the substrate and the enzyme. This means that less H2O2 can be broken down, which produces less foam.

4.a) Describe the effect of low (pH 2) and high (pH 12) pH levels on catalase activity. Both low pH levels and high pH levels produced a low amount of catalase activity.

b) Explain this effect at the molecular level. Extreme pH levels such as pH 2 and pH 12 breaks the hydrogen bonds between the molecules. This denatures the enzymes, disallowing the substrate to fit into the active site to be broken down.

5.a) Use the graphs to help you describe the optimum conditions for the catalase enzyme. In both graphs, the optimum conditions for catalase activity is easily shown by the highest point on the graphs, which represents the most amount of foam produced between the test tubes. The more foam produced, the more catalase activity occurred in the test tube. On the temperature graph, the highest point was at 27ºC, which means that at that temperature, there was the most amount of catalase activity. On the pH graph, the highest point occurred at pH 10. Combining these two conditions along with the macerated potato would ensure the optimal conditions

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