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Introduction

Aim: To investigate the effect of concentration on the rate of enzyme catalysed reaction. To investigate the effect of concentration on the rate of enzyme catalysed reaction I must know all the factors that affect it in order to investigate in this. Here are all the factors: Temperature - Enzyme like it warm but not too hot. Enzymes are biological catalysts, which speed up chemical reactions. They work most efficiently at the optimum point (37?C). If they are below 37?C they will work slower. If the temperature goes over 45?C they will be denatured due to the high heat. PH - The pH affects the activity of enzymes. It depends on what solution there surrounded in. Each enzyme works most efficiently at a certain degree of acidity or alkalinity. Example - the enzymes in our stomach (protease) are surrounded by hydrochloric acid at a pH of 2 (strong acid), which is the condition it works most efficiently at. Concentration - If the solution is made more concentrated it means it contains more particles and therefore speed up a reaction. If the solution has a weak concentration it will have less particles and therefore a slow reaction will occur. All enzymes are biological catalysts. Living organisms have thousands of chemical reactions going on inside them. Obviously the quicker the reaction the better it is and it's important that the temperature is at a correct level to speed them up. If the temperature is high enough, above 45?C they will be denatured because enzymes are living organisms and too much heat has an affect on them. Enzymes do all sorts of different processes. Each one is designed to do a specific job. ...read more.

Middle

The yeast only breaks whatever there is. If the solution has a strong concentration it will breakdown a lot of particles in that solution as when a solution has a weak concentration it will breakdown less particles in that solution. Preliminary Work Before I start my investigation I must do a trial run to see if I need to make any changes to my plan. I first decided to use 5ml of hydrogen peroxide and yeast to react together. This was a very fast reaction and I was not able to collect any reliable evidence. After this I used 2ml of each solution and it was at a correct rate of reaction. I decided to run the experiment for one minute but it was a short time as the reaction wasn't near complete. I changed the time to two minutes as this gave better results. From my preliminary work I had a slight problem. When I added the hydrogen peroxide with the yeast to react together in the test tube I quickly put the rubber bung on top. This was not a good idea because as soon as the hydrogen peroxide and yeast are mixed together the reaction starts and oxygen will be produced but it will escape instead of being collected. To over come this problem I decided to leave the bung on top and insert a needle so that no oxygen will be lost. From my preliminary work I decided to use a range of 1.0, 0.8, 0.6, 0.4 and 0.2 molar This range of concentration is perfect to collect the evidence needed. ...read more.

Conclusion

The step I would add is to "remember to do this every time by pouring the hydrogen peroxide in the test tube and inject the yeast through the needle". This step is important because if both hydrogen peroxide and yeast are put through the needle then they would react and the oxygen produced will escape, making it an unfair test. My method gave evidence that is reliable and therefore it can always be counted on to be correct. The procedures in my method are accurate and precise. This is important because the method is how to collect reliable evidence. It has all the details on what to do, which are put into easy stages to follow and understand. This is done to ensure reliable evidence to be obtained. I have obtained enough evidence to draw a firmed conclusion. I did five repeats for each concentration making a total reading of 25. From the repeats I calculated an average result. These results are correct and accurate as shown by my graph and also means that I can draw a final conclusion that is correct. To improve my plan I could use pipettes to measure the quantities more accurately. If this was done I could ensure more accurate concentrations. If the concentration is accurate more reliable results would been obtained. Another improvement I could do is to do more background research in order to produce a much better plan. I also could of measured the reaction with a different technique. Further work could have been carried out to get additional relevant evidence. I could of done this investigation by varying the other factors to investigate in that. Different acids and enzymes could have been investigated under the same experiment; from this it will give my conclusion more support. I ...read more.

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