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What factors could have an effect on the rate of respiration in yeast?

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Introduction

What factors could have an effect on the rate of respiration in yeast? There are many factors that could affect the rate of respiration in yeast. Such as the temperature the yeast respires at as at different temperatures the enzymes in yeast work faster or slower at breaking down the glucose this is because the yeast enzymes will have more or less energy with which to break down the glucose. The amount of yeast will also have an effect on the results, as if we are to use different amounts in each experiment it will form an unfair test. Another factor that could affect our investigation is the percentage of glucose in the yeast. I must also make sure to leave all experiments undisturbed during the course of respiring, this means they cannot be stirred or let air get to them. I have chosen to investigate the affect the percentage of glucose concentration has on the rate of respiration in yeast. I will use an experiment to determine whether the yeast's rate of respiration will be quicker, slower or if it does not change when the percentage of glucose concentration in it is varied. ...read more.

Middle

Each experiment will be repeated a second time so as to find any anomalous results and if any are found that experiment will be repeated once more to verify the correct result. When dealing with yeast and alcohol I must make sure not to inhale or consume in any way anything during the experiment as a lot of it may be harmful in someway. Also if any glass is broken for any reason it must be cleared up properly and safely. I found some secondary information on the Internet and put it together with some of my background knowledge to form the following information. FERMENTATION is the breakdown of sugars by bacteria and yeast using a method of respiration without oxygen (anaerobic respiration). It involves a culture of yeast and a solution of sugar, producing ethanol and carbon dioxide with the aid of the enzymes. This is an 8-10 step process requiring different enzymes each time, but it can be simplified like this. All the ENZYMES are protein chains of amino acids. They exist in the form of helix structure with hydrogen bonds holding the pitches together. On the amino acid molecules, there is R a group. They react with each other to form peptide bonds, transforming the chain into a 3-dimensional structure. ...read more.

Conclusion

The rate of reaction table could be seen in the obtaining evidence along with the other results. The formula for calculating the rate of the reaction is: The change in volume of carbon dioxide (y) The change in time per minute (x) It is a shame that I did not have enough time to do the rest of the experiment such as the sugar concentration of 50% because I do not have enough time to complete it. Though I have not done the other experiments I still have enough of the results to conclude the experiment. Although I did not do 50% sugar concentration I could still say that the best sugar concentration will still be 100% because it has the nearest osmotic pressure on both the solution and the yeast cells. The main conclusion here is that the most important factor is the osmotic pressure that effects the whole experiment. Due to my prediction what I have predicted was nearly all right except on which was that the amount of carbon dioxide given off will increase as the concentration of sugar increase was wrong because that it is exactly the opposite. Except that the other prediction is the same as the result. ...read more.

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