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How does the concentration of hydrogen peroxide affect how the enzymes in potatoes work?

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How does the concentration of hydrogen peroxide affect how the enzymes in potatoes work? In this experiment I will see the affects of reacting different concentrations of hydrogen peroxide with the enzymes in potatoes. Potatoes contain the enzyme catalyse and this enzyme reacts with the hydrogen peroxide to form oxygen and water. The reaction can be seen by the formula: 2H�O� 2H�O + O� (hydrogen peroxide) (water + oxygen) I will obtain sets of results by varying the concentration of hydrogen peroxide used; this will affect the rate of reaction and, in turn, oxygen given off within a certain time period will vary accordingly. I will change the concentration of hydrogen peroxide by diluting it with distilled water. It is vital that certain factors are kept constant throughout the investigation in order to carry out a 'fair test'. The factors that must remain un-altered are: * Temperature. This has to be kept the same because enzymes work best at different temperatures and if the temperature is closer to their optimum temperature in one experiment compared to another this will cause the investigation to become unfair because as you get closer to the optimum temperature the rate of reaction increases. Also if the temperature gets too high then the enzymes can be killed and will therefore not react. We kept the temperature at around 20 degrees Celsius (room temp.) ...read more.


I will account for any water lost before the gas has been delivered through by subtracting the amount the water level has lowered from the final result i.e. if 2cm� of water was lost before the experiment and the final water level after 2 minutes reaction time was 6cm� then the result would be 6cm� - 2cm� = 4cm�. I predict that as the concentration of hydrogen peroxide increases the amount of gas produced will also increase. I think this because as the solution becomes more diluted there are less particles of reactant between the water molecules, which means collisions with the catalyse particles and hydrogen peroxide particles are less likely. Also, after researching from a textbook, I found that enzymes are also biological catalysts and speed up chemical and biological processes. This is because the particles stick to the surface of the catalyst where they react and if the concentration is increased then there are going to be more particles for the catalyst to react with thus speeding up the rate of reaction. As catalyse is an enzyme the above statement should apply and therefore the rate of oxygen given off when the concentration is high should be greater than when the solution is more diluted and there are less reactant particles. I carried out the method as I described in the planning section, however, in the planning section the method states that all the potato chips should be cut ...read more.


Making these alterations should help to gain more accurate and reliable results. As mentioned earlier, I thought that my method was reliable because although improvements could be made, such as the ones above, the existing method was still adequate in giving concluding results and anomalies didn't have a major affect on conclusions as they were ignored. I feel that I have enough results to be able to produce strong conclusions because 3 results for each concentration are substantial as anomalies can be interpreted and averages calculated. Six different concentrations are also all that is necessary because trend lines and patterns can still be easily seen. If I wanted to gain further evidence that an increase in the concentration of the reactant increases the amount of gas produced I could perform other investigations because all experiments should confirm this statement. This is because when the concentration is increased it just means there are more particles to react with and so there will be more collisions and this will speed up the rate of reaction. Finally, I believe that the amount of evidence I provided is good enough to confirm my conclusion because the above theory, the conclusions drawn from my results and my prediction all agree that an increase in the concentration of hydrogen peroxide reacted with the enzymes in potatoes will increase the rate of reaction. Alex Tarvin 11E ...read more.

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