Yeast Culture Lab
Yeast is a one-celled, microscopic organism, which is part of the fungi kingdom. Yeasts do not make up a single group (Smith & Smith, 2012). Yeasts use organic material as a means of making energy, which make them chemoorganotrophs (Smith & Smith, 2012). Carbon is procured primarily from hexose sugars, such as fructose and glucose. Yeast need either oxygen for aerobic cellular respiration or for species that are anaerobic, but also have aerobic methods creating energy (Smith & Smith, 2012). There are no species of yeast species that are known to grow only anaerobically. Yeasts thrive in an environment with a slightly acidic ...view middle of the document...
For the experiment, the materials needed are the following:
(1) Test tube rack
(4) 18mm x 150 mm culture tube
(4) 10 ml graduated cylinder
(1) Eye dropper
(1) Ammonia mixture
(1) Distilled water
(1) Sugar mixture
(1) Microbe mixture
(4) Yeast packets
The following methods are the steps needed to carry out the yeast culture experiment:
(1) Label the four test tubes with the different materials that will be mixed with the yeast. The labels should read: Ammonia, Control, Sugar, and Microbe. The time and concentration of each solution should be under the identification label on each tube. The data sheet should also reflect these materials for thorough recording of the results of the experiment.
(2) Each tube should be filled with 10 ml of its specific solution.
(3) In a separate container mix a yeast suspension solution and add two drops of this solution into each tube.
(4) Prep the microscope.
(5) Take one drop of solution out of each tube and observe it under the microscope. Document the results of each solution on the data sheet. Repeat this step at intervals of 24, 48, 72 and 96 hours.
(6) Once the experiment has been completed, record the data and analyze the results as well as clean up and put away the equipment.
After the experiment was carried out and, the data was analyzed, the hypothesis was found to be accurate in that the yeast and other solutions in the test tubes became active, especially the sugar solution. In all instances the yeast mixture physically expanded in the test tubes and the sugar solution expended twice as much causing the solution rising to the rim of the test tube.
The sugar and yeast solution levels grew exceeding the 200 count level while the other solutions only exceeded the 100 count level. Below is the population graph, which displays a constant rise in all solutions, which suddenly peak off and decline just as quickly. The data on the graphs clearly shows that the population peaks and then declines because the reproduction rate was increasing without a death rate. As the yeast solution began to die off, they died at the same rate because reproduction ceased and there were no additional resources. Once the resources were depleted, the population died off.
|Intervals |Control |Limited reproduction |Additional Food |Introduced |
| | | | |Predation |
|1 (0 hours) |5 |6 |6 |6 |
|2 (24 hours) |13 |11 |12 |12 |
|3 (48 hours) |94 |64 |167 |79 |
|4 (72 hours) |77 |43 ...