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My aim is to find how temperature affects the rate of anaerobic respiration in yeast.

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Biology coursework Anaerobic respiration in yeast. Aim My aim is to find how temperature affects the rate of anaerobic respiration in yeast. Plan I wish to make my experiment as safe as possible so I will be wearing safety goggles at all times so as not to have any yeast in my eyes. I know that during anaerobic respiration in yeast CO2 + alcohol are given off. I know this because I carried out an experiment in the 3rd form to see what was given off in anaerobic respiration in yeast. We also learned in this experiment that the alcohol is toxic to the yeast and the yeast will die if too much alcohol is produced. I will measure how much CO2 gas is given off during a specified amount of time to ensure that the alcohol does not affect the yeast and to see how fast the rate of anaerobic respiration is occurring. I have also learnt from my 3rd Form experiments that anaerobic respiration in yeast is an enzyme-controlled reaction. I also know that temperature and pH affect the enzyme-controlled reactions. I have chosen temperature because it is hard to mix acids to the right pH and I can set water baths at to degrees difference to prove the Q10 effect. There are three methods I could use to find the amount of gas that is given off in this experiment. ...read more.


Measuring + Observations I will make sure it is a fair test by only having one variable and keep all other factors constant. The factors that could effect this experiment are: Amount of yeast, the pH of the yeast, the glucose (fuel) that the yeast has been given, the amount of air that should not be reacting with the yeast, the temperature of the yeast. I will ensure that this is a fair test by making sure that is only they temperature which I will vary. All other factors will be kept constant so as to not affect the results. Range I will take 3 readings at every temperature. I am using this number because I can formulate an average of the three, which should be closer to the actual amount. I will be taking the readings at 10oC intervals from 10oC to 60oC. I have chosen this range because it goes to distances above and below the predicted optimum temperature. I will be working to 1cm3 degree of accuracy for the reading of the CO2 gas. I plan to repeat all results that do not fit the trend of the other results in that temperature. This is necessary because it will bring my average of the temperature more reliable and so closer to the actual amount. Apparatus The apparatus I will be using in this experiment will be: * Boiling tube * Delivery tube * Gas syringe (20cm3) ...read more.


In Experiment No 2 at 30oC I found an anomalous result. The amount of gas collected was much lower than it should have been if it were to fit the pattern of the Q10 effect. This could be because I began to take measurements before the yeast had reached the temperature it was meant to be at, causing it to respire slowly until it reached the temperature. In our experiment, small enough gas syringes were not available and were not as able to freely move. This meant we collect CO2 gas in an inverted measuring cylinder filled with water. If I had to repeat the experiment I would use the apparatus originally requested for. This would make my results more reliable because it is easier to read the measurements from a gas syringe than from a half submerged measuring cylinder. I chose not to repeat the experiment No 2 at 30oC because I had already obtained many other results at that temperature. By disregarding the anomalous result I am able to calculate a more reliable average and so my result will become more reliable. I wish I could have researched the subject a little more but this however would only have reiterated what I had already found out. It would make me feel more confident of my conclusion. However, if I had done any more reading I am sure that I would not have found new material to change my conclusion but the same information to make sure my conclusion was correct. Tom Gulden 4H 1 ...read more.

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