5.6 describe a simple experiment to investigate carbon dioxide production by yeast, in different conditions

Effect of temperature on carbon dioxide production

C –  We will Change the temperature of the solution in the range of 20-30ºC. We do not want the temperature too high or the enzymes in the yeast will denature

O –  Yeast (10 grams) – whether it will anaerobically respire. The same species of yeast will be needed, same mass of yeast
R  – We will repeat each temperature the yeast is in the water bath 3 times to make the test reliable
M  – The volume of carbon dioxide released by the yeast respiring anaerobically after 20 minutes. This will be measured by the diameter of a balloon (Gas inside the balloon is CO2). Measured with ruler in cm^3 . May test with lime water (If limewater goes cloudy, it shows presence of CO2)s

S –  pH, concentration of yeast, concentration of sugar, equipment

 

Effect of sugar concentration on carbon dioxide production

C  – The mass of sugar in grams (A range of 10-50 grams of sugar) because yeast need glucose to respire.
O –  10 grams of yeast  which will need to be the same species as different species of yeast respires differently
R –  at least 5 times for result reliability

M –  This will be measured by the diameter of a balloon (Gas inside the balloon is CO2) Measured with ruler in cm^3 .May test with lime water (If limewater goes cloudy, it shows presence of CO2)

S  – pH, temperature and type of yeast, temperature, species of yeast

 

Effect of pH on carbon dioxide production

C – The pH of the yeast solution – you can use buffers to change and maintain the pH of the solution (pH 5, 7, 9)

O  – 10 grams of yeast

R –  at least 5 times to ensure reliability

M  – The volume of carbon dioxide released by the yeast respiring anaerobically after 20 minutes. This will be measured by the diameter of a balloon (Gas inside the balloon is CO2). Measured with ruler in cm^3. May test with lime water (If limewater goes cloudy, it shows presence of CO2)

S – The level of sugar, temperature, species of yeast

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