Under aerobic conditions, the catabolism of glucose begins with glycolysis to convert sugar into pyruvate. During pyruvate synthesis into Acetyl CoA, molecules of ATP are produced. Acetyl CoA is then transferred to the mitochondria where the Krebs cycle takes place. The Krebs cycle further produces ATP with the addition of CO2 as the by-product.

Yeast cells are facultative organisms that can use aerobic respiration and fermentation. But in this experiment, yeast cells are in the presence of oxygen performing sugar metabolism, which we measure by the amount of CO2 production. The objective of this experiment is to determine the concentrations of ethanol that have a toxi

c effect on the amount of CO2 produced under aerobic conditions. We expect to find that as doses of ethanol concentration increases, the production of CO2 will decrease in Saccharomyces cerevisiae. We hope to see results similar to our hypothesis, since it is known that ethanol is toxic to yeast cells. The importance of this study is to gain valuable information on the performance of the organism, whether an inhibitor or non-inhibitor is used to measure its activity.

Figure 2 is the ethanol concentration on the x-axis plotted against the linear rate of CO2 production. Each bar on the graph shows a decrease of CO2 production as ethanol concentration increases in relation to the results of Figure 1. Bar graph is used because we measured CO2 production from different test tubes with different concentrations and different yeast mixtures.

The results obtained from the experiment suggest that the effect of increasing doses of ethanol does inhibit the production of CO2, but not completely, because at 12% and 15% there is still some minimal metabolism. These results from Figure 1 and Figure 2 mean that the glucose metabolism in the presence of oxygen in yeast cells decrease when more concentrations of ethanol is increased, causing growth of Saccharomyces cerevisiae to practically stop. Our 0% tube, which contained no ethanol, produced maximally. Therefore, we can conclude that when yeast is under the influence of increasing doses of ethanol, the production of CO2 decreases, meaning that cell metabolism is slowing down.

Table 2 is created from calculating the slope (rise/run) for the log phase of the graph in Figure 1. At 0% - 0.14 ml of CO2 produced/min., 3% - 0.13 ml of CO2 produced/min., 6% - 0.11 ml of CO2 produced/min., 9% - 0.07 ml of CO2 produced/min., 12% - 0.04 ml of CO2 produced/min. and 15% - 0.02 ml of CO2 produced/min. The linear rate of CO2 production for each concentration of ethanol decreases minimally.

Some common words found in the essay are:
Materials Methods, Acetyl CoA, Sources ATP, Introduction ATP, Campbell Reece, co2 production, Measuring Saccharomyces, test tube, yeast cells, test tubes, production co2, concentrations ethanol, ml co2, ml co2 produced/min, co2 produced/min, figure 1, saccharomyces cerevisiae, amount co2 produced, increasing doses ethanol, test tubes water, co2 production constant,
Approximate Word count = 1360
Approximate Pages = 5 (250 words per page double spaced)