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Investigating Respiration in Yeast

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Investigating Respiration in Yeast Aim To investigate the effect of different concentrations of glucose on respiration in Yeast. Introduction Yeast Yeast is simply a single-celled fungus, found on the surface of fruit, feeding on sugar. Yeast can multiply itself by a process called budding. A large number can be formed in a short time. Respiration Respiration is basically the breakdown of glucose to feed a cell, supplying it with energy. There are two types of respiration: aerobic and anaerobic respiration. Aerobic respiration requires oxygen to carry out, but anaerobic respiration does not need oxygen. Anaerobic respiration causes lactic acid, which contributes to cramp. The equation of aerobic respiration is: Glucose + Oxygen --> Carbon Dioxide + Water + Energy C6H12O6 6O2 6CO2 6H2O Experiment We can measure respiration with a simple experiment - which is the one I am doing. We measure the volume of Carbon Dioxide with different glucose concentrations. This gives us our results. Variables I will measure the rate of Carbon Dioxide produced. This is the dependent variable. I will change the concentration of glucose. This is the independent variable. Other variables have to be controlled as these can also affect the reaction. ...read more.


50cm3 - 3 50cm3 - 4 50cm3 - 5 50cm3 - See graph on the next page Preliminary Conclusion I can conclude from this that respiration is a simple method including the breakdown of sugar unless the concentration of Yeast in the experiment has been made higher or lower. I have measured the change in Yeast in the above table and it has proved my Prediction. I am satisfied with my results but I believe I could have improved by: * Recording results twice for every concentration * Increasing the variety of concentrations for the experiment * Checking every piece of equipment that is clean before experiment Results 0% Concentration Glucose concn Volume of Water (H2O) in burette cm3 Volume of Carbon Dioxide (CO2) produced in cm3 Accumulative Volume cm3 Time 1 2 3 1 2 3 Avg 1 min 50cm 50cm 50cm 0cm 0cm 0cm 0cm 0cm 2 min 50cm 50cm 49cm 0cm 0cm 1cm 0cm 0cm 3 min 50cm 50cm 49cm 0cm 0cm 1cm 0cm 0cm 4 min 49cm 49cm 48cm 1cm 1cm 2cm 1cm 1cm 5 min 49cm 46cm 48cm 1cm 4cm 2cm 2cm 3cm 5% Concentration Glucose concn Volume of Water (H2O) ...read more.


This is not a problem, however. It is to be expected because each column of result was a different experiment. The suitability of the method was very good and clear and was easy to adhere to. There are only two seen improvements - by not being able to control the amount of agitation the yeast solution receives before the experiment may stop the validity of the experiment. The second improvement is that all the equipment should have been washed thoroughly beforehand so that no foreign germs may having effects while the experiment is taking place. To continue with the experiment, I had to make sure I had enough reliable evidence to make a prediction, a reliable experiment and a conclusion. I achieved this by trying a Preliminary Investigation before starting the main one. My hypothesis was correct and results were reliable evidence to suggest a larger experiment would be successful. I learned some safety precautions and method advances after the Preliminary Investigation to ensure a safe and valid experiment. Further work could have been tried to try to enhance the experiments legality. I could have used more experiments on the batch of Yeast to make sure that its contents were 100% pure. I could have used apparatus to agitate each sample of Yeast together so that they are identical to each other. Page 1 of 7 Darren Pinder 11T ...read more.

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