To investigate the effect of temperature on the rate of anaerobic respiration in yeast.
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Biology Coursework: Planning Aim: To investigate the effect of temperature on the rate of anaerobic respiration in yeast. Prediction: I predict that the yeast will respire faster up to the temperature of 50°C. This is because for yeast to anaerobic respire it uses enzymes and enzymes are denatured past 50°C. Because of this I think that the yeast will respire fastest at 50°C and once past that temperature it will start to slow down and once all of the enzymes are denatured. I think that the fastest rate of respiration will be 50°C because every 10°C rise in temperature doubles the rate of respiration, but after the maximum temperature every 10ºC rise the rate of reaction will decrease by the same amount it increased. Method: To do this experiment I will be using the following pieces of equipment, a boiling tube, a delivery tube, a water bath, a thermometer an solution of 0.1g of yeast to 20cm3 of water, sugar, cooking oil, a timer, a beaker, a measuring cylinder and hot water.
The bubbles will be carbon dioxide given off by the yeast. To make sure that I don't have any bubbles from the initial aerobic respiration that happened when the yeast was mixed with the sugar before the oil was added. I will test this three times so I can see if had any anomalous results. I will record my results on my results table. I will be using two variables in this investigation: 1) The variable temperatures to see which is the optimum for the yeast 2) The amount of sugar- to see if it makes a difference to the rate of reaction The temperature is needed to be a variable so that I can investigate if the rate of reaction doubles in a rise of 10ºC. the variable of the sugar means I will be able to find out if more bubble are made at a certain temperature with more sugar.
Another way for this to be made fair would be to use an electronically controlled water bath. Another factor that needs to be made fair is the time the yeast is given to adjust to the temperture. I have decided to give the yeast 10 minutes to adjust. I will count the time using a stop-watch. Temp ºC Sugar (g) 1 min 2 mins 3 mins 4 mins 5 mins 6 mins 7 mins 8 mins 9 mins 10 mins 20 2 1 20 2 2 20 2 3 20 4 1 20 4 2 20 4 3 30 2 1 30 2 2 30 2 3 30 4 1 30 4 2 30 4 3 40 2 1 40 2 2 40 2 3 40 4 1 40 4 2 40 4 3 50 2 1 50 2 2 50 2 3 50 4 1 50 4 2 50 4 3 60 2 1 60 2 2 60 2 3 60 4 1 60 4 2 60 4 3
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