Showing Cellular Respiration through Alcoholic Fermentation
The experiment was conducted to determine the impact different yeast amounts had on yeast fermentation. It was hypothesized that the more yeast added the more CO2 would be produced. The carbon dioxide production was measured in the fermentation of yeast with solution of no yeast in test tube 1, 1mL yeast in test tube 2, and 3mL of yeast in test tube 3 over a period of twenty minutes. All of the yeast amounts produced CO2, but test tube 3 was the most efficient of the three.
This lab was to investigate fermentation, a cellular process that transfers the energy in glucose bonds to ATP. The energy in ATP can then be used to perform cellular work. Fermentation is an anaerobic (without oxygen) process; cellular respiration is aerobic (using oxygen ). All living organisms, including bacteria, produce ATP in fermentation or cellular respiration and then use ATP in their metabolism.(Campbell, 2008)
Cellular respiration is a sequence of three metabolic stages: glycolysis (in the cytoplasm) and the Krebs cycle and the electron transport chain in mitochondria. Fermentation involves glycolysis but doesn’t involve the Krebs cycle and the electron transport chain, which can’t function at low oxygen levels. Two common types of fermentation are alcoholic fermentation and lactic acid fermentation. Alcoholic fermentation begins with glycolysis, breaking glucose into two molecules of pyruvate with and yielding 2 ATP and 2 NADH molecules. In anaerobic environments, the pyruvate (a 3-carbon molecule) is converted to ethyl alcohol (ethanol, a 2-carbon molecule) and CO2. In this process the 2 NADH molecules are oxidized, replenishing the NAD+ used in glycolysis (Campbell, 2008).
In our lab, we investigated alcoholic fermentation in backer’s yeast (a single-celled fungus). When oxygen is low, some fungi, including yeast and most plants, switch from cellular respiration to alcoholic
Cited: Berg, Jeremy. Biochemistry: 5th Edition. 2002. Campbell, Neil. Biology: 8th Edition. Ed. Beth Wilbur. San Francisco: Pearson Education,2008