Terry M. Bella
The state embedded task involves factors that affect the fermentation by Saccharomyces cerevisiae of molasses as a sugar source. This task is assigned to be carried out by our students in New Haven during the winter months in the midst of a unit on population dynamics. Students investigate the effect of temperature or food supply (molasses concentration) on the carbon dioxide production of the yeast. The amount of carbon dioxide produced is supposed to reflect the activity of the yeast population. This lab investigation would be more useful if carried out during a unit on enzymes because it clearly demonstrates the effects of temperature on enzyme activity.
Students find that yeast incubated at temperatures higher than room temperature result in faster and greater carbon dioxide production. Conversely samples incubated below room temperature will have decreasingly lower production correlated with the decrease in temperature. Students also find that there is a positive correlation between molasses concentration and enzyme activity.