Cellular respiration and fermentation - Lab Report Example

The key materials used are the following: 10 percent sucrose solution; 10 percent glucose solution; peas; distilled water; phenol red; yeast stock; wax pencil; water bath; hot plate; test tubes of various sizes; beaker; test tube corks and holders; test tube rack. The idea behind the test tubes of varying sizes is to create a respirometer using two sizes of test tubes, for the experiment involving the yeasts. A practice session involves filling the smaller tube, measuring 15 x 125 mm with water, placing that inside a 20x150 mm test tube, and inverting to the point where the air bubble in the smaller test tube is as small as can be made from the process.

In the actual experiment, three different test tubes are filled with two thirds of either ten percent sucrose solution, ten percent glucose solution, or distilled water, and then topped off to the brim with yeast suspension. The inversion method practiced above is utilized to mix the solutions and form the respirometers. The respirometers are allowed to incubate for one hour, while placed in a water bath set at 37 degrees Celsius. The gas bubble heights are measured after the period of incubation.

The idea is to be able to undertake a comparison of how the three sources of food in the test tube compare with regard to their suitability as food for yeast. This is the first part of the experiment (Experiment 7 n.d., pp. 59-61). In part two of the experiment., 10 peas that were either soaked, not soaked, and soaked and boiled were placed in each of three different test tubes, fulled with water up to the two-thirds level, and covered with corks. After an hour and a half, two drops of phenol red were placed in each of the three test tubes containing the seeds, more when no color was visible or the color is too vague/thin.

The results of the color observations were tabulated. (Experiment 7 n.d., pp. 59-61) The first part of the experiment measured the amount of respiration from the