Volume of CO2 Production in Yeast Over Sixty Minutes Through Six Different Treatments

Introduction

Fermentation is a “process that provides a mechanism by which some cells can metabolize organic nutrients and produce ATP in the absence of oxygen”(Gregg etal., 2019). During glycolysis when the cells are in an anaerobic situation, NAD+ cannot be produced as usual. If the cell is not producing NAD+, the cell “would stop glycolysis and ATP production”(Gregg etal., 2019). To prevent this cells use fermentation. “Alcohol fermentation is the formation of alcohol from sugar”(Farabee, M.J.).

This experiment studied the carbon dioxide production in yeast over a period of sixty minutes.

“Yeast… convert glucose to pyruvic acid via the glycolysis pathways” to produce ATP (Farabee, M.J.). The independent variable was the volume of carbon dioxide and the dependent variables were the time and the treatments. The null hypothesis was the volume of carbon dioxide would have no change between the six treatments over the sixty minutes.

Get quality help now

Writer Lyla

Verified writer

Proficient in: Biology

5 (876)

“ Have been using her for a while and please believe when I tell you, she never fail. Thanks Writer Lyla you are indeed awesome ”

+84 relevant experts are online

Hire writer

The alternative hypothesis was the volume of carbon dioxide would have a change between the six treatments over the sixty minutes. The predictions were that water would have little activity because it was the control, glucose would have moderate activity because it is a monosaccharide, sucrose would have little activity because it is a disaccharide, lactose would have little activity because it is a disaccharide, lactose + lactase would have high activity because lactaid increases, and starch would have no activity because it is not a single sugar.

Results

The mean amount of carbon dioxide produced in the fermentation culture with water was 0.

175 mL, with 0.5 M of glucose was 2.175 mL, with 0.5 M of sucrose was 2.3 mL, with 0.5 M lactose was 0.2 mL, with 0.5 M of lactose + lactase was 2.6 mL, and with 1% starch was 0.275 mL. The average volume of carbon dioxide in the yeast culture among all six treatments (p=0.0001) shows that “at least one of the treatments is significantly different from the others”.

Because of this, the t-test was run and the letters were ‘A’ for lactose + lactase, sucrose and glucose, and ‘B’ for starch, water, and lactose. The standard deviation of the water fermentation culture was 0.206. The standard deviation of the glucose fermentation culture was 0.67. The standard deviation of the sucrose fermentation culture was 0.909. The standard deviation of the lactose fermentation culture was 0.271. The standard deviation of the lactose + lactase fermentation culture was 0.883. Lastly, the standard deviation of the starch fermentation culture was 0.222.

The volume (mL) of CO2 vs. time (min) scatterplot graph shows the linear trends of the data for thee six treatments. The independent variable is the volume of carbon dioxide and the dependent variable is time. The treatments are labeled by different lines as shown in the key to the right of the graph.

The equation of the best fit line for water is Y(water) = 0.175. The equation for the best fit line for glucose is Y(glucose) = 0.085 + 0.0335*X. The equation for the best fit line for sucrose is Y(sucrose) = -0.02 + 0.03567*X. The equation for the best fit line for lactose is Y(lactose) = 0.16 + 0.000833*X. The equation for best fit line of lactose + lactase is Y(lactose + lactase) = -0.06 + 0.0445*X. The equation for the best fit line for starch is Y(starch)=0.105 + 0.003*X.

The volume (mL) of CO2 vs. treatment bar graph shows the relationship between the volume of carbon dioxide and each treatment with the standard error included. The independent variable is the volume of carbon dioxide and the dependent variable is each of the six treatments. The standard error on each bar represents the true mean of all of the data.

Discussion

The null hypothesis was rejected; therefore, the alternative hypothesis, the volume of carbon dioxide would have a change between the six treatments over the sixty minutes, was supported. At the end of the experiment, water, lactose, and starch had the smallest amount of activity and glucose, sucrose, and lactose + lactase increased as the time increased. The prediction previously stated that lactose + lactase would have the highest activity and that was proven to be correct.

However, sucrose was predicted to have little activity and it ended up having the second highest activity with glucose following right behind. Starch proved the prediction of no activity correct because it is not a single sugar. Some limitations could be human errors such as incorrect measuring, leaving the solution out of the water too long, or allowing it to sit longer in the water for the 15 minute intervals.

Literature Cited

1. Farabee, M.J. CELLULAR METABOLISM AND FERMENTATION, www2.estrellamountain.edu/faculty/farabee/BIOBK/BioBookGlyc.html.
2. Gregg, C., B. Trabona, M. Brooks, J. Reiland and S. Pomarico. (2019) Biology 1208 Biology Laboratories for Science Majors. Hayden McNeil Publishing, Plymouth, MI.