The Effect of Ph on Fermentation Rate

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Introduction: Fermentation of yeast can be used to produce bread and alcoholic beverages. Yeast fermentation is the breakdown of sugars in the absence of oxygen. The proper enzymes need to be capable of breaking the food’s chemicals in a useful way. Yeast is capable of using some, not all sugars as a food source. Yeast can metabolize sugar in two ways, aerobically, with the aid of oxygen or anaerobically without oxygen. The net equation for more than two dozen steps involved in the aerobic respiration of glucose is: C6H12O6 (aq) + 6O2 --> 6H2O (g) + energy (36-38 ATP + Heat) But when yeast ferment sugars anaerobically, CO2 production will cause a change in the pressure of a closed test tube system, since no oxygen is being consumed. We can monitor this pressure as an indication of the rate of anaerobic respiration & metabolic activity of the organism. A gas pressure sensor will be used to monitor the fermentation of the sugar. The net equation for the ten steps involved in anaerobic respiration of glucose is: C6H12O6 (aq) --> 2CH3CH2OH (aq) + 2CO2 (g) + energy (2 ATP + Heat) Both alcoholic fermentation and aerobic respiration are multi-step processes that involve the transfer of energy stored in the chemical bonds of a metabolite (usually glucose) to bonds in ATP (Adenosine Triphosphate). The energy stored in ATP can then be used to perform cellular work such as provide energy for biosynthetic reactions, growth/repair processes, active transport, etc. All organisms use aerobic respiration and/or fermentation (anaerobic respiration) to produce ATP to power their cellular processes. When anaerobic respiration happens in animals it is called Lactic Acid Fermentation. Lactic Acid Fermentation can only produce 2 ATP (as in alcoholic fermentation) but ethanol is not produced. Lactic acid is toxic to cells, which means anaerobic respiration can only occur for short
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