What are the differences between aerobic respiration and fermentation? What are the processes for both?
Fermentation is the opposite of aerobic respiration; this is why fermentation is also called anaerobic respiration (respiration without oxygen). The balloon on top of the bottle with yeast in it inflated (or should have) because the yeast, having little oxygen available, metabolized the sugar anaerobically, producing CO2. (There was also a tiny amount of alcohol produced) Of course, in the bottle without the yeast, nothing happened, because there were no organisms to break down the sugar.