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Respiration of yeast

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Respiration of yeast Fermentation is the incomplete breakdown of glucose in plants, resulting in the formation of alcohol and carbon dioxide, and the release of a little energy. Also fermentation is an anaerobic reaction, which means without oxygen. Planning For my biology courses work I investigated the amount of carbon dioxide produced when yeast is combined with a sugar solution. This reaction is called fermentation. The reaction follows this equation: Glucose + yeast --> alcohol + carbon dioxide The following are factors that will affect the rate of fermentation: * Concentration of sugar solution, * Type of sugar, * Temperature of the environment , * Age of the yeast, * The weight and amount of the yeast, * Temperature of water surrounding the reactions The factor chosen to be varied is the concentration of sugar within the solution. ...read more.


This is because heat make will make the yeast atoms vibrate and split up causing yeast enzymes to combine and react producing carbon dioxide (c02). Method: * We collected and set up the apparatus as shown on the diagram, * Weighed the yeast to 1.5g, * Filled and boil the kettle, * Emptied the kettle content into the beaker, * Added cold water to make the temperature 400c by using a thermometer, * Poured 20ml3 of 0% sugar solution into a test tube, * Put the 1.5g of yeast into the sugar solution, * Started the stopwatch, * Made sure the bung and delivery tube was securely on top of the test tube with the reaction in it so that carbon dioxide doesn't escape, * Place a test tube ...read more.


Conclusion: Looking at my results I have come to the conclusion that the higher the percentage of sugar solution the more carbon dioxide is produced in the amount of time given. The relationship between my prediction and the results are similar. Evaluation: I think my method explains what I did in my experiment and is simple to follow and easy to understand. Looking at my result table I can see some anomalous results this might be because of carelessness or improper use of equipment this is why the experiment was repeated three times. If I were to do the experiment again I would make sure I had more time to ensure the results are more accurate. For example I would make sure the yeast used are at the same weight and assure that the starting temperature of the water surrounding the reaction is remains at 400c. ...read more.

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