ICT In Biology(TBC 3013)DATA LOGGER Group members: Yee Hon Kit D20091034822 Yee Chin Tien D20091034824 Ngang Huey Chi D20091034861 Sharifahroqaiyah D20091034851
I WILL SURVIVE! Anaerobic respiration: Fermentation
Biological Principle: In the absence of oxygen, yeast will undergo anaerobic respiration. Yeast converts glucose into ethanol and carbon dioxide. So, the carbon dioxide given out reflect the rate of anaerobic respiration. Glucose was fermented because this sugar can pass rapidly into the cell and enter directly into metabolic pathways
ENGAGE Can she keep diving under the water after the diving tank that stored compressed gas such as oxygen have depleted? Some organism such as bacteriacan survive in the absence of oxygen, why? Anaerobic respiration occurs in oxygen-poor marsh muds.
Procedure: 4 grams of yeast was measured by the electronic balance. Glucose solution was prepared in a beaker. Different concentration of glucose solution was prepared as follows: 5%, 10% and 15% The glucose solution of 5% was boiled under the Bunsen flame to evaporate any dissolve oxygen in the solution. This glucose solution was cooled down by the ice to prevent the heat produced killed the yeast during the fermentation. The carbon dioxide sensor was connected with the Data Logger.
Glucose solution was then mixed with the yeast in the reagent bottle under the water bath with temperature 30 oC. Water bath was prepared to maintain the temperature as heat produced will affect the reaction during anaerobic respiration. A layer of oil was added on the top of the solution to prevent gas trapped in the solution. The carbon dioxide sensor sealed the reagent bottle of the mixed solution The reagent bottle was put under the water bath for 10 minutes. The amount of carbon dioxide was recorded at each 5 seconds interval. Steps 4 to 11 are repeated but the concentration of glucose solution is changed to 10% and15% respectively.
From the graph and table, it is shown that the fermentation of 5% of glucose produced the highest amount of CO2 and highest rate of fermentation. While fermentation of both 10% and 15% of glucose have produced almost same amount of CO2 in the same period of time, both also have steady rate of respiration.
Questions Look at your table ,why does the carbon dioxide level change? Which fermentation of glucose produced higher amount of carbon dioxide gas? Why? What does the graph tell you about the change in carbon dioxide level during fermentation. What is the end product of fermentation? State the equation of yeast fermentation.
Answer The change of carbon dioxide level indicated that the yeast fermentation of glucose have begun. Or anaerobic respiration has initiated by yeast. 2. In the same period of time, fermentation of yeast in glucose 5% have produced higher amount of carbon dioxide. This can be explain as in high concentration of glucose such as 10% and 15%, the increase in glucose concentration led to in the increase in fermentation time. Besides, when the glucose content increased, the glucose uptake rate decreased, this will affect the rate of fermentation. Thus, as longer time is required for fermentation of yeast to occur, it have reduced the amount of CO2 produced for both 10% and 15% of glucose fermentation. 3. Fermentation of different concentration of glucose will have different rate of fermentation and different amount of end product in fixed time. 4. Ethanol, carbon dioxide and energy. C6H12O6 --------------> 2C2H5OH + 2CO2 + 2ATP
Discussion The fermentation of glucose, which occurs primarily when the glucose concentration is high or when oxygen is not available. The cells have a low energy yield of only about 2 ATP per mole of glucose metabolized. The stoichiometry of this reaction is C6H12O6--------------> 2C2H5OH + 2CO2 + 2ATP where represents chemical energy utilized in the growth processes.
The influence of different glucose concentration on metabolic activities of yeast wasevaluated by the overall amount of C02 and rate of reaction. In high concentration of glucose such as 10% and 15%, the increase in glucose concentration led to in the increase in fermentation time. Besides, when the glucose content increased, the glucose uptake rate decreased, this will affect the rate of fermentation. Thus, as longer time is required for fermentation of yeast to occur, it have reduced the amount of CO2 produced for both 10% and 15% of glucose fermentation. Conversely, for the same reason which mentioned above, fermentation of 5% glucose have produced the higher amount of CO2 and with the highest rate of fermentation.
ENHANCE Give another example aside from the given picture of fermented food and discuss the making of this fermented food.
Unique Feature of This Activity Amounts of carbon dioxide produced can be detected and measured accurately (measured in every 10 seconds). It is impossible to measure the amount of carbon dioxide accurately using conventional method. Less work need to be done by the students. The experiment can be carried out for a longer period of time and the results will be recorded automatically during that period of time. The pattern of amount of CO2 production changes can be observe along with the experiment.