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Lab Report Biology Essay

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Results: One result of this experiment was a standard curve of the density of yeast cells in relation to absorbance (Figure 1). We found that as the density was increasing, the absorbance was increasing (Figure 1). We used the equation of the standard curve from Figure 1 to determine the density of cells at different time intervals by multiplying the slope of the line from Figure 1 (y=16.691x) with the absorbance level we had measured for each solution. The density (cells/mL x 10^6 was then plotted against the time intervals (Figure 2). The yeast grew faster in the 5.0pH environment since the density nearly doubled in the same time it took the yeast from the 2.3pH environment to increase by ½ the original density (Figure 2). Also, the yeast …show more content…

The yeast grew faster in the environment with a pH of about 5 (Figure 2). Some evidence of a carrying capacity was shown (Figure 2). The yeast grown in the pH 2.3 environment had a carrying capacity of about 0.308 (Figure 2). However, there was no definitive evidence of a carrying capacity for the yeast grown in the pH 5 environment since the population did not stabilize (Figure 2). It is possible that the carrying capacity for that environment is about 0.828, but more tests would need to be done to solidify the legitimacy of that estimate (Figure 2).
The results of our experiment mirror the results of Heard and Fleet’s experiment. They determined that different yeast species excel in different pH environments. They found that one species, Saccharomyces cerevisiae, particularly excelled in a pH environment between 3.0 and 3.5 (Heard & Fleet, 1988). The yeast used in our experiment thrived in a similarly low pH environment of about 2.3 (possibly higher depending on the true carrying capacity of the yeast in the pH 5 medium) (Figure 2). Our species of yeast may overpower other yeast species if placed in a more competitive environment. However, not all experiments agree with ours. An experiment by Fleet, Charoenchai, and Henschke resulted in no significant changes in growth rates in wine yeast population between medium pH environment levels of 3.0 and 4.0 (Charoenchai, 1998). Our results do not prove a significant difference, …show more content…

Creating the best possible environments for yeast growth can help increase culinary yeast production. Growing yeast in an environment with a pH around 5 will increase production as opposed to growing yeast in an environment with a pH around 2.3 (Figure 2). This can increase revenue for many companies. In addition, medical professions can benefit from this experiment. Knowledge of which environments encourage yeast growth will help create remedies for yeast related afflictions. Forcing yeast to live in a more acidic environment, such as a pH of 2.3, will discourage growth as opposed to a location with a higher pH (such as 5) (Figure 2). All in all, there are many real-world applications for this

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