BIO 157
The effects of temperature on the rate of fermentation by yeast
Introduction:
The intent of this experiment was to discover the different ways temperature would affect fermentation by yeast. The various temperatures would give a better outlook on which was the most effective on activating the yeast. This experiment was interesting because we got to better understand the process of fermentation and how it generates adenosine triphosphate (ATP) by the process of substrate-level phosphorylation. In which was learned is only possible through a small range of temperatures. Fermentation is the name of the process that the yeast uses to make carbon dioxide. It is a form of anaerobic digestion, the energy formed from ATP comes from the oxidation of carbohydrates. Fermentation is important in anaerobic conditions when there is no oxidation phosphorylation to maintain the production of ATP. Fermentation is the absence of the electron transport chain and takes a carbon source, such as glucose, and makes products like lactic acid or acetate (Gaden, E. L. 1959).
Before fermentation takes place, one glucose molecule is broken down into two pyruvate molecules, also known as glycolysis (Purves, 2004). Glucose is mixed with the yeast because it contains the enzymes that will be used for energy to accelerate the chemical reaction that causes the yeast to rise and create carbon dioxide when it is heated, just like making bread. Three things are required for fermentation. First, fungi or bacteria must be present (yeast). Second, no oxygen must be present. Third, an organic compound must be present (sugar). How fast fermentation occurs depends on temperature. The starting compounds determine the products. Sugar produces carbon dioxide and alcohol (“Fungal Factories” 13 Nov. 06).
In this experiment our variable, Temperature, affects the rate of fermentation. It was discovered that only a small window of temperature, around 37 degrees Celsius, is the most reactive or fastest fermenting temperature. This temperature created the most amount of Carbon dioxide the fastest in all three
