The Production of Pyruvate and Acetaldehyde During the Fermentation of Glucose.

2333 Words Nov 18th, 2012 10 Pages
The glycolysis pathway is nearly universal in biological systems. Glycolysis is the sequence of reactions that converts glucose to pyruvate with the concomitant formation of ATP. Three fates of this pyruvate produced exist. In this practical the production of pyruvate and acetaldehyde by fermentation of glucose is established. A series of test tubes was set up each containing glucose and yeast suspension in buffers at different pH values. These test tubes were incubated for an hour at 37℃. Trichloro-acetic acid solution was then added to the first 2 of the 4 test tubes prior to centrifugation at 2500g. Solid ammonium sulphate and freshly prepared sodium nitroprusside were added to these tubes and colour observations made. For the
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Acetaldehyde is then converted into ethanol, CH3COOH. ( This reaction occurs under low oxygen, or anaerobic conditions. Organisms that convert pyruvate to ethanol, or ferment under anaerobic conditions are called facultative anaerobes. Yeast are examples of facultative anaerobes that undergo alcohol fermentation. The carbon dioxide gas given off in this process is useful in the process of bread baking, causing the dough to rise. (
Many bacteria are capable of converting pyruvate to lactic acid. This process is called lactic acid fermentation. It is a process similar to alcohol fermentation, but in this case, the three-carbon pyruvate molecule is converted to a three-carbon lactic acid molecule having the formula CH3CHOHCOOH. Unlike alcohol fermentation, no carbon dioxide is given off. A three-carbon molecule is simply converted to another three carbon molecule (
Some bacteria and yeasts organisms are unable to cope with the presence of oxygen. These organisms use fermentation as a method of obtaining energy in the form of ATP. Because the production of lactic acid frees up NAD+, the process of glycolysis can continue. Lactic acid fermentation is the simplest type of fermentation. In essence, it is a redox reaction. In anaerobic conditions, the cell’s primary mechanism of ATP production is glycolysis. Glycolysis reduces – that is, transfers electrons to NAD+, forming NADH. However, there…