Log 5: Cellular respiration and fermentationQuestionHow will different concentrations of sugar affect the rate of anerobic fermentation by yeast in theproduction of wine?ApproachTo prepare the experiment each group must add 325ml of grape juice to their Erlenmeyer flask atroom temperature. The flask must then be labeled with the instructor’s name, class session, group #, and the amount of sucrose (sugar) in grams that will be added to the solution by that group. Once the Erlenmeyer flask is labeled and with the correct amount of grape juice, then each group must measure their designated amount of sugar to mix with the grape juice. The concentrations of sugar were 0g, 25g, 55g, 85g, 115g, and 150g. The sugar would then be added to the solution and mixed with a sterilized stir-rod, making sure not to leave any sediment at the bottom of the flask. Using a pipette of 10ml, the mixed solution was extracted and weighed to find the initial density and the initial specific gravity (density/.998). Then a balloon was attached to the top of the flask so that we could see how much CO2 would be released at the end of the experiment. A rubber band was wrapped about the tip of the flask to create an even tighter seal and the initial circumference of the balloon was also recorded. The solution fermented for 14 days, and the final circumference of the balloon was taken, along with the final density and specific gravity. Which each group then used to calculate their alcohol content percentage.ResultsThe results indicate the optimal concentration of sucrose (relative to the 325ml of grape juice) was 85 grams for fermentation by yeast. We can see that it has both the highest percentage of alcohol at 15.9% and it produced the most CO2 with the circumference of the balloon expanding 25cm. Yet there was some variation in the Alcohol content most likely caused by human error. Discussion The process of fermentation occurs when anaerobic organisms such as yeast need to generate energy without the presence of oxygen. The sucrose that was added to the wine was broken down into glucose which was then further broken down into 2 pyruvate molecules in Glycolysis.Therefore, the fermentation process will ultimately convert the sugar in the solution to an acid (alcohol) and carbon dioxide. The sucrose was just the reactant needed for yeast to carry out fermentation. So, what might have happened in the solution with 0 g of sugar added was that is stopped to ferment simply because it ran out of reactants once the sugar from the grape juice was depleted. ImprovementsAreas of improvement could be in the collection of the data samples for initial and final specific gravity. After fermentation the wine is supposed to have a lower specific gravity than before since the we saw that CO2 has been released from the solution into the balloon, but some groups recorded a higher specific gravity after fermentation which is unlikely. The error here may have been in not considering the weight of the cup while weighing the 10ml samples to calculate density, incorrect use of the pipette, spills, or incorrect calculations of SI, density, or alcohol content. All these areas could be improved by double checking samples and calculations or by using more overall caution when performing the experiment. Without these errors, the variations in the data (alcohol content especially) would not have been as dramatic. Future DirectionsHow well did the amount of CO2 produced reflect the alcohol content after 14 days? Further analyzation of the CO2 produced could help with straightening out the human error after the fact,since the alcohol content and CO2 production are related. Could using different types of sugars affect the rate of fermentation? The type of sugar used maybe another impactful variable that could affect the rate of fermentation since the sucrose needs to be broken down molecules like pyruvate anyway. Another substance may reduce the steps