Find out what affect the surface area of a potato chip has on the rate of reaction between the Catalase enzyme in it and Hydrogen Peroxide.

Paul Jefferyes 11E Mr Rowell 08/05/07

Catalase Investigation:

Aim: to find out what affect the surface area of a potato chip has on the rate of reaction between the Catalase enzyme in it and Hydrogen Peroxide.

This investigation is going to see how quickly the catalase enzyme breaks down the hydrogen peroxide in different lengths of potato slices (1cm in width and breadth).

Enzymes are biological catalysts that speed up chemical reactions in our cells. Catalase is a fast acting breaker enzyme that works on Hydrogen peroxide.

Hydrogen peroxide is highly caustic (it burns) so you must take great care when near it, and wear eye and hand protection if you are handling it. It is used as a decontaminant in water supplies. Unfortunately H2O2 (hydrogen peroxide) is also a natural metabolite of many organisms (including potatoes), which would kill them if not for the catalase enzyme they produce to decompose the H2O2 into harmless oxygen and water. This is a very important reaction in all organisms, as the H2O2 would destroy cells if not broken down quickly. Our own liver has a very high concentration of catalase to remove H2O2 as quickly as possible so minimal damage is done.

There are two main types of enzyme, Builders and breakers (Catalase is a breaker) these diagrams explain how they work:

Builders:

Breakers

Not all reaction attempts result in products:

For reactions that involve two or more molecules hitting together to react, chemists know that not all the collisions that molecules have are successful.

The theory to try and explain why not all reaction attempts by molecules are successful is called the collision theory.

Collision Theory:

A chemical reaction can only occur between particles when they collide (hit each other), and they have the correct orientation for the reaction to occur successfully. Particles may be atoms, ions or molecules. There is a minimum amount of energy which colliding particles need in order to react with each other. If the colliding particles have less than this minimum energy, then they just bounce off each other and no reaction occurs. This minimum energy is called the activation energy. The faster the particles are going, the more energy they have. Fast moving particles are more likely to react when they collide. If the colliding molecules have enough energy and the right orientation, then they have a better chance of forming the end product or products. If the colliding molecules have enough energy but not the right orientation, then they have little chance of producing products. If the colliding molecules have the right orientation but not enough energy, then they cannot react and so again would not form the end products. This theory is not only for simple elements and molecules, it also applies to Enzymes and organic reactions.

I plan to test the rate of reaction between Catalase and H2O2 like I did in my 1st preliminary investigation. My 1st preliminary experiment recorded the height of bubbles given off from different lengths of potato chips. This proved inaccurate so in my main investigation I shall trap the oxygen given off in a measuring cylinder under water (as shown in diagram). I also will chop the ends off of the chips to keep the lengths in proportion and so that if the same experiment was done again then it could be accurately done.

Preliminary experiment 1:

Preliminary results:

In my second preliminary test I changed the temperature instead of the size of chip. I tested this by heating equal lengths of potato and equal quantities of H2O2 together to different temperatures.

Preliminary experiment 2:

Preliminary results 2:

Main: