What Happens When Can Yeast Metabolize?

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Yeast is alive because it can to metabolize and respond to environmental changes. The purpose of the first experiment was to determine whether yeast can metabolize. The bromothymol blue solution with yeast changed from blue to yellow. Bromothymol blue is an acid-base indicator that turns yellow in the presence of acid. The color change indicates that carbonic acid was formed from the reaction of water and carbon dioxide, a byproduct of metabolization. These results accept the hypothesis: if yeast can metabolize, then the bromothymol blue solution should turn yellow from the production of carbon dioxide. Only the bromothymol blue solution with yeast turned yellow, suggesting that the yeast caused the color change. The yeast consumed sugar, produced…show more content…
Only the heated solution caused the balloon to expand, suggesting that the increase in temperature is linked to the balloon’s expansion. Furthermore, as the solution was only heated to 60°C, no water vapor was produced to fill the balloon, suggesting the gas was produced solely by the yeast. Thus, the yeast reacted to the heat, supporting the claim that yeast can respond and is alive. Sources of error in this experiment could have included incorrect preparation of solutions. The solutions of yeast, water, and sugar, could have been measured incorrectly causing the control and experimental solutions to be different. For example, in the response experiment, a yeast solution was prepared without sugar mistakenly and thus had to be prepared again. This suggests that other errors in preparation and measurement could have been encountered. For the future, careful measurements using clean uncontaminated flasks would eliminate possibilities of such error. A source of error for the metabolism experiment involves the yeast’s yellow hue. It is possible that the color of the yeast caused the solution to look more

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