Fermentation Lab

Fermentation Lab: Conclusion & Evaluation of the Effect of Type of Carbohydrate on Amount of CO2 Produced
IB Biology/Topic: 3.7
05 February 2013

Question: Which type of carbohydrate, glucose, sucrose, or starch, will produce the greatest amount of fermentation over the class period? Why?

Hypothesis: If the carbohydrate starch is added to the set up of yeast, then it will create the greatest amount of fermentation because starch is a polysaccharides made up of chain of glucose molecules.

Conclusion: Overall the resulting data supported the alternative hypothesis, in which the type of carbohydrate makes a difference on the amount of CO2 produced. When deducing the results, it was concluded that sucrose made the greatest amount of fermentation in the set up of yeast out of the three types of carbohydrates. In the data collected from sucrose, there was more carbon dioxide (CO2) produced in three of the four graduated cylinders, because the rate of fermentation can be determined by measuring the amount of CO2 produced. Therefore, in the end those three graduated cylinders had an excess amount of fermentation product, with the fourth graduated cylinder having some water molecules still left. Our results from sucrose conclude two graduated cylinders with +50(ml) of CO2, one graduated cylinder with 40.0(ml) of CO2.

Limitations of Experiment: Our experimental design for the fermentation lab helped answer our experimental question fairly. What worked well is the fact that the paper clips that were used to be inserted in the rubber tubing worked efficiently as to being able to bend the tube into the upside down graduated cylinder that’s inserted in the 250ml beakers. The bending of the rubber tubing allowed the solutions from the test tube to flow into the graduated cylinder easily. Although, what did not work out so well in our experiment is the fact that the one-whole stoppers did not want to compress into the test tubes tightly enough so the liquid solution would not come out. Another problem was the fact that the glass bend connected to the one-whole stopper was too long in height, which made it hard for the liquid solution to travel up the glass bend and to sufficiently make way to the graduated cylinder.

Improvement: In reference to the limitations given in the previous subsection, there are improvements that could be made amongst the one-whole stoppers and the glass bends. The one- whole stoppers could be manufactured to fit a certain type of test tube, so there would be specific sizes of one-whole stoppers for the certain size of test tubes.