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An experiment to investigate the effect of temperature on the rate of fermentation between sucrose and yeast.

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'A' Level Biology Investigation An experiment to investigate the effect of temperature on the rate of fermentation between sucrose and yeast. Student number: 5122 By Anthony Parker Introduction Defining the Problem The impoverished Bill decided to brew his own wine, however he noticed that the mixture was not bubbling. Due to his knowledge from GCSE biology, he knew that there was no fermentation-taking place, therefore he knew there was no alcohol being produced. He knew that the production of alcohol depended on certain limiting factors, and passed his information on to a friend studying 'A' Level Biology to investigate why he was not producing any alcohol. Background information The reason for me investigating the temperature is that the place where Bill has situated his apparatus is relatively cold. I know that most enzymes operate at a temperature of 37?C (body temperature). Under Bills stairs, it is considerably colder than that. This low temperature is affecting the enzymes activity that takes place, therefore, reducing the amount of anaerobic respiration that is taking place. The process of fermentation happens due to anaerobic respiration. The formula for anaerobic respiration is: - Glucose ==> Ethanol + Carbon Dioxide + Energy C6H12O6 ==> 2CH3CH2OH + 2CO2 + Energy When an organism has oxygen to breath, the process is called aerobic respiration. ...read more.


This is important in the form of temperature and pressure in an industrial process such as fermentation. Enzymes work so well in living organisms, because body temperature is roughly 40( C, which is an enzymes optimum temperature. Other temperatures can be used with enzymes that are called Hyperthermophiles, which are not able to grow below 70�C and Psychrophiles that work at a temperature of -10�C. This means they can be used in industry when freezing is needed or excess heating, like the ones put into meat products to make it more tendered. Enzymes are also very specific, this means they will only work in certain circumstances and on certain cells. This is when the correct enzyme and substrate are present, this is what makes them so good for working in certain circumstances and places in the body when it come to the medical implications of enzymes. Enzymes can be affected by different factors, such as pH, temperature, surface area, inhibitors, pressure, and enzyme and substrate concentration. In an industrial environment to get the highest possible, yield from your reactants. You need to make sure all of these factors are accounted for, because if just one of them is wrong you could destroy the whole batch or continuous production. I will investigate them by means of an electrical thermostat water bath. ...read more.


After 45?C the amount of bubbles decrease, this tells me that the enzyme is denaturing, due to the enzymes active site changing so that substrates do not fit in. My standard error bars show that my graph is correct to 95% confidence. Therefore, I can be 95% confident that my results are correct. If I wanted to reduce these limits I could take more results. Evaluation Although this experiment is very simple, it provided good results, my small error bars on my graph showed this. I could improve the size of these error bars if I took more readings, or used a more accurate method. A good method that I could use would be to use a gas syringe, this would give me a real figure in cm3 and would improve the accuracy of the results. One problem that we did encounter in producing accurate reliable results was that the amount of bubbles being released by the pipettes was high and very fast. If next time I used a gas syringe and increased the volume of solution then the results would be come much more reliable. Another problem we seemed to encounter was the water bath was not at an exact temperature all of the time. This is because the water bath worked on a negative feedback loop, generating a fluctuation in temperature of +- 3?C but this was happening all though our experiment, so it would not affect the overall results. 2 Anthony Parker - 5122 ...read more.

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