Assignment task: Design an experiment
Saccharomyces cerevisiae is a species of yeast that is commonly used in food production. Under optimal environmental conditions, S. cerevisiae undergoes aerobic fermentation, a by-product of which is carbon dioxide (CO2). Therefore, measuring the production of CO2 can serve as a proxy for measuring aerobic fermentation. There are many factors that can affect aerobic respiration, including temperature, nutrient availability, and exposure to pollutants/toxins. you will examine the effect of different environmental conditions on aerobic fermentation in S. cerevisiae. As a reference, the typical method of activating yeast (starting aerobic fermentation) is incubating 1 tsp. of yeast in 120 mL warm water with 1 tsp. sugar. Whatever your experimental design, be sure to include controls, both positive and negative, and make sure it is reproducible!
Procedure
1. Identify ten variables that may affect aerobic fermentation in yeast. Record the variables in Table 5.
2. From your list of variables, select three to test. Form a hypothesis regarding how each variable may affect aerobic respiration in yeast.
3. Determine the positive and negative controls for your experiment.
4. Line up five clear cups (if you do not have five cups, you can perform experiments sequentially, washing the cup thoroughly between each treatment), and label each cup with one treatment or control type.
5. Place a predetermined amount of yeast and the corresponding treatment in each experimental cup, and set up your controls. Be sure you have enough yeast for each treatment. Let the yeast incubate in the treatment for 15 minutes.
6. Using a ruler, measure the height of the foam created by the output of CO2. Take this measurement by aligning the 0 of the ruler with the top of the waterline and measuring up to the top of the foam. Record this measurement for each treatment.
7. After completion of data collection, create a table including a title, units, and any other useful information.
8. Select the appropriate type of graph, and report the data you collected.
9. Write a lab report for this experiment.