The Effect of Glucose Concentration on Anaerobic Respiration in Yeast
Yeast, also known as a saccharomyces cerevisiae, is single celled eukaryotic cells that are in the kingdom fungi and are unicellular organisms which normally reproduce asexually by budding at a very high rate. Scientists quite often decide to work with yeast because of its features fast growing rate and the fact that yeast's DNA can be easily manipulated. Some types of yeast can be found naturally on plant or in the soil. Also it is worthwhile mentioning that yeast feeds on sugar very well, and so that I decided to use glucose.
My independent variable will be the concentration of glucose solution. To make sure that that my test will be fair, I will make sure that the water temperature, volume of yeast and glucose and the timings will be as constant as possible. The only thing that I'm going to change is the concentration of the glucose, so I will be able to see whether the concentration of glucose will have an effect on the respiration of yeast or not. I also will also make sure that while conducting an experiment, I will keep the flasks absolutely clean all the time. This will help to avoid the chance of bacteria building up, and so the competition over the glucose will be avoided.
The mass added and the intervals of adding must be controlled, because it might affect the overall outcome. In order to get good fermentation environment for the yeast, the incubator will be kept around 30c.
My hypothesis for this experiment is that the greater the concentration of glucose will be added, the faster the rate of respiration will be. This is because more glucose added to the yeast will mean more glucose to break down, therefore producing ethanol and carbon dioxide. Also to support my hypothesis I would mention that, more concentration of glucose will result in the more heat energy produced and so more molecules will move around and collide.
Anaerobic Respiration equation: glucose → ethanol + carbon dioxide (+ energy released)
Aerobic Respiration equation: glucose + oxygen → carbon dioxide + water (+ energy)
Concentration of Glucose
Measured by measuring cylinders/pipettes, as a percentage to the water solution
Concentration: 10%,15%,20%,25% and 30% to volume of distilled water
Measured by measuring cylinder