An investigation into the effects of substrate concentration on an enzyme reaction between catalase (potatoes) and hydrogen peroxide.

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An investigation into the effects of substrate concentration on an enzyme reaction between catalase (potatoes) and hydrogen peroxide.

Prediction.

        I predict that if you increase the concentration of Hydrogen Peroxide, the speed of reaction will also increase but the rate of reaction will always slow the longer the reaction takes place.

Background knowledge

        Enzymes speed up reactions but are not used up in the reaction so they can be used more than once. Enzymes are a biological catalyst made of protein molecules, all living organisms have, and need enzymes to live without them chemical reactions in the organism would take to long and the organism would die all enzymes are affected greatly by theses two conditions temperature and the Ph level, at low levels the enzyme works slow, this is because there would be less energy at a cold temperature so as the molecules are moving slower the number of collisions in a set amount of time would be lower than at a high temperature also there would be less of the energy needed for a collision to cause a reaction. When the temperature increase the rate does but at to high of a temperature the protein molecules making the enzyme denature and they stop working. Ph also affects the rate of an enzyme, different enzymes like different ph levels, example enzymes in the stomach like acidic conditions and enzymes in the small intestines prefer alkaline conditions this is due to the hydrogen ion concentration on the active site region. Competition for the active site between the natural substrate and a inhibitor which has a similar structure to the natural substrate can also lower the enzymes rate of activity also inhibitors who cause permanent distortion to the active site will slow the rate of enzyme activity for example cyanide. You can also control the rate of reaction with increasing or decreasing the rate enzyme activity this can be done by increasing or decreasing the enzymes or substrate concentration. Factors which affect the rate of reaction are substrate concentration for example at low concentrations not all the enzymes active sites are being used there is simply not enough substrate molecules, but increase the substrate concentration and more enzymes come into use and so the rate of reaction increases in till it comes to a point where the active sites of all enzymes are being used so even if you increase the concentration of the substrate further it will not increase the rate of reaction.

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Enzymes work on a lock and key mechanism

        The molecules are thought to have holes of a certain shape depending on the enzyme, this means that only substrates with a similar structural shape to the hole will react. There could be many substrates that can fit in that hole or only one substrate depending on the complexity of the hole.

        The enzyme I am dealing with is catalase it speeds up the breakdown of hydrogen peroxide into water and oxygen            

Hydrogen peroxide                   ...

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