No carbon dioxide was produced for Tubes 1

No carbon dioxide was produced for Tubes 1, 2, and 5. Since no carbon dioxide was produced, cellular respiration did not occur. Tube 1 contained albumin (protein) while Tube 2 contained butter (lipid). For this experiment, yeast was used as the experimental subject. Since yeast does not require proteins and lipids, these substrates were left untouched. Meanwhile, Tube 5 is the negative control. It contained distilled water, which is neither a substrate nor a sugar, so it was expected that cellular respiration will not occur. Yeast cannot digest food in water, thus it was also left untouched. On the other hand, carbon dioxide was produced in Tubes 3 and 4. This means that cellular respiration occurred. Tube 3 contained glucose (monosaccharide) while Tube 4 contained sucrose (disaccharide). Glucose and sucrose are both simple sugars. Since yeast requires simple sugars, these substrates were used up for its cellular respiration. Tube 3 with glucose is the positive control since it is commonly known that glucose is the one that is broken down for cellular respiration. Compared to this, the result for Tube 4 with sucrose had a higher volume of carbon dioxide produced and a higher rate of carbon dioxide production than that of Tube 3 with glucose. This is because