Dr. Gerard P. McNeil
Biology 202 Lab GGJ
4/21/2018
LAB REPORT Lab #9- Yeast Fermentation Dates of performed work: 3/26/18 Date submitted: 4/23/18
Abstract
Yeast are unicellular fungi which act as facultative anaerobes. This means that yeast is able to produce ATP by aerobic respiration while oxygen is present, but are also capable of anaerobic respiration if oxygen is not available. This is called fermentation. Fermentation allows glycolysis to continue in the absence of oxygen. The type of anaerobic respiration used is alcohol fermentation, which produces ethanol. …show more content…
6) Finally, tube 7 was prepared the same way as tube 4; with 1mL yeast, 1mL sucrose, and then filled to the top with buffer.
7) After each tube was prepared, it was swirled to prevent settling. They were then carefully placed in fermentation chambers and inverted.
8) Fermentation chambers 1 through 6 were placed into the same candle jar. Fermentation chamber 7 was placed into a separate candle jar.
9) The candles inside both jars were lit, and then the jars were sealed. The purpose of the candles is to use up the remaining oxygen in the jar.
10) When the flame extinguishes, this indicates that there is no oxygen remaining in the jar, thus insuring aerobic respiration cannot take place and anaerobic respiration can begin.
11) Finally, once the flame is extinguished, the first jar, which contains fermentation chambers 1 through 6, was placed into a 37oC water bath, while the second jar, which contains only fermentation chamber 7, was left at room temperature (approximately 25oC).
12) Every ten minutes for an hour, the amount of CO2 in mL that had evolved was observed via the marks on the test tubes and recorded.
13) At the end of the hour, these results were plotted and compared. …show more content…
After 40 minutes, 0.25 mL of CO2 evolved. No more evolved after that. Tube 2, which contained glucose, and tube 4, which contained sucrose and was kept at 37oC evolved the most CO2 compared to the other tubes. Of the other tubes that contained sucrose; tube 6, which included NaF and was also kept at 37oC, evolved only 1.25 mL CO2 and tube 7, which was kept at room temperature, evolved 1.50 mL CO2. Tube 3, which contained fructose, also evolved as much CO2 as tube 6, but at a different rate. Finally, tube 5, which contained arabinose, evolved no CO2 at