In this lab we examined how the rate of fermentation is influenced by the type of substrate, and activators and inhibitors. We used four fermentation tubes in which we separately combined yeast with MgSO4, pyruvate, ethanol, and glucose.
At five minute intervals we recorded the volume of gas produced in each fermentation tube. Our results are displayed in the graph. Our results supported the prediction that pyruvate is an activator of fermentation. But our results did not support the prediction that MgSO4 is an activator of fermentation. This could be due to experimental errors, such as the fermentation tube not being clean, or the glucose being added at a different time. Our results indicated that as fermentation proceeded and ethanol concentration rose, the rate of fermentation slowed down. From five to ten minutes there was a sharp increase in fermentation, then as the ethanol concentration rose, it started to level off.
Effects of Temperature on Fermentation Rates
In this part of the lab we examined the relationship between respiration rate and temperature. We combined yeast separately in four fermentation tubes with four glucose solutions that had been equilibrated to four different temperatures. We then recorded that volume of carbon dioxide produced in each fermentation tube at five minute intervals. Our results are displayed in the graph. We measured the rate of metabolism by measuring the amount of carbon dioxide produced in milliliters per minute. Our results showed that the rate of metabolism increased with increased temperature. The correlation between metabolism and temperature is positive. As temperature increased, the metabolic rate increased. The difference in rate between the 10 degrees celcius and the 20 degrees celcius tubes was not equal to the difference in rate between the 30 degrees celcius and the 40 degrees celcius tubes. Instead the