to explain the differences among the differences of the rate of respiration of the yeast.
MATERIALS AND METHODS
The Smith Fermentation Tube was used to determine the effect of the nature of substance on rate of cellular respiration of yeast. Six fermentation tubes were prepared. Each tube was labelled from one to six. 15 mL of solution with 10% concentration were added in the respective tube for starch, lactose, sucrose, glucose, fructose, and distilled water. 15 mL of distilled water and 15 mL 10% yeast suspension were poured to each fermentation tube as seen in Figure 1. All the mixtures were gently shaken at the same time without spilling the mixtures.
The opening of the tube was immediately covered with cotton balls. This was to prevent air from coming in and out of the tube. The tubes were tied together in upright position. Any external disturbance on the tube was avoided. The CO2 formed at the vertical arm of the tube were measured by a commercial 12-inch ruler. This was done by using the ruler to measure the height of the area covered by bubbles at the vertical arm for 30 minutes at regular five-minute interval. All the results were recorded and tabulated.
The volume of evolution of CO2 was obtained by using the