Lab report Biology

Respiration Applications of Fermentation

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Respiration Applications of Fermentation

Introduction

Fermentation is the process by which yeast cells produce alcohol and carbon (IV) oxide in the from glucose concentration when there is no oxygen presence. This involves the anaerobic type of respiration that breaks down glucose without oxygen molecules. Fermentation involves glucose as the reactant in the presence of yeast which has enzymes that catalyze the breakdown of glucose into alcohol and carbon dioxide. The byproducts of this fermentation process include alcohol, carbon dioxide, energy and lactic acid depending with the type of fermentation involved. The conditions for this process to occur include favorable temperature of about 300 C, glucose concentration, yeast concentration and absence of oxygen gas (Tran & Unden, 1998). The fermentation process is anaerobic type of respiration which means that glucose is broken down in absence of oxygen and the end products being alcohol, lactic acid and carbon dioxide gas.

The alcoholic fermentation differs from lactic fermentation in that it occurs in cell cytoplasm with no energy yielded whereas lactic fermentation occurs in mitochondrion and yields energy. The type of fermentation performed in the lab is the alcoholic fermentation (Schultz & Weaver, 1982). The use of calibrated pipette measured the fermentation, carbon dioxide produced and the bubbles formed.

The real world applications of fermentation include production of alcoholic beverages, baking of bread, and production of yogurt from milk and in biofuels applications. The most used substance product in household setup is the alcoholic beverages. The end products of fermentation include lactic acid, alcohol, water, energy inform of ATP and carbon dioxide (Tran & Unden, 1998).

It is essential for relative high concentration of both yeast and glucose in fermentation process. This is to make maximum yielding of the fermentation products. The ideal concentration for this process is 25% for both concentrations (Schultz & Weaver, 1982). This provides optimum condition and equilibrium for enzymes in yeast cell to enhance fermentation process. Yeast requires glucose concentration to catalyze its breakdown by the enzymes in the yeast cell. Glucose is an energy source for the cell since it produces energy inform of ATP when oxidized through aerobic respiration.

The variables for this experiment are the glucose and yeast concentration as well as the carbon dioxide gas. The type of yeast species used in this experiment is the Saccharomyces Cerevisiae. The hypothesis for the experiment is that yeast and glucose concentrations influences the rate of carbon dioxide produced in fermentation process.

Methods and materials

The various materials used for this experiment include four flasks, four test tubes, tap water filling the flaks up to 5cm from above, 1ml pipettes, glucose and yeast concentrations, binder clips, rubber tubing and thermometer. The actual and initial evolved values of carbon dioxide in this case are 0.00 and 0.70 respectively. The values were measured using the spectrophotometry instrument and calculated by subtracting the initial value from the final value in each stated value observed. The carbon dioxide value was measured by the values of the calibrated pipette and using the stop watch to time the duration whereas the rubber tubing remains clamped over this time. This is to enable the carbon dioxide gas to push the concentration as it moves from the concentration. I repeated the experiment several times to correct errors and adjust the setup correctly.

Results

Trial 1 table and graph

Carbon dioxide production actual and evolved for 20 minutes

actual concentration in ml	Carbon dioxide gas evolved
0.39	0.00
0.36	0.00
0.35	0.01
0.34	0.02
0.33	0.03
0.32	0.04
0.25	0.2
0.17	0.28
0.1	0.35
0.03	0.42
0.09	0.54
0.15	0.6
0.22	0.67
0.23	0.68
0.25	0.7

Trial 2 table and graph

Carbon dioxide production actual and evolved for 20 minutes

actual concentration in ml	Carbon dioxide gas evolved
0.45	0
0.42	0
0.41	0.01
0.4	0.02
0.39	0.03
0.38	0.04
0.37	0.05
0.36	0.06
0.39	0.01
0.37	0.03
0.35	0.05
0.33	0.07
0.29	0.11
0.27	0.13
0.26	0.14
0.24	0.16
0.21	0.19
0.2	0.2

Discussion

The respirator setups differed in that they had different concentrations. The setups from 1 to 4 had the glucose and yeast concentration suspension as 0 and 3, 1 and 0, 1 and 3, 3 and 3 respectively. These different yeast and glucose concentrations affect the rate of fermentation by providing the enzyme quantities that could work for the amount of glucose involved. The molecular levels inhibit or enhance the rate of fermentations by providing insufficient or appropriate conditions for the enzyme reactions respectively. Scientists use the spectrophotometry instrument as another instrument to measure the fermentation and respiration (Gregory, Bond & Lovley, 2004). I repeated the experiment severally to get appropriate values and measurements. The human errors in the experiment include wrong and inconsistent measurement of the values using the instruments provided. In future I will make sure the instruments are functioning well before doing the experiment.

References

Tran, Q. H., & Unden, G. (1998). Changes in the proton potential and the cellular energetics of Escherichia coli during growth by aerobic and anaerobic respiration or by fermentation. The FEBS Journal, 251(1‐2), 538-543.

Schultz, J. E., & Weaver, P. F. (1982). Fermentation and anaerobic respiration by Rhodospirillum rubrum and Rhodopseudomonas capsulata. Journal of Bacteriology, 149(1), 181-190.

Gregory, K. B., Bond, D. R., & Lovley, D. R. (2004). Graphite electrodes as electron donors for anaerobic respiration. Environmental microbiology, 6(6), 596-604.