Saccharomyces Cerevesiae Research Paper

Antibacterial Agents Inhibit the Yield of Saccharomyces cerevesiae

Andrea Peña
Biology 1401-C

Department of Biology, The University of Texas-Pan American, Edinburg, Texas 78539

October 22, 2012

Abstract – The problem that led to this experiment was that when antibiotics were mixed with yeast cells, the antibiotics decreased the yield of yeast cells. However, this is unexpected result because yeast is not a bacteria and therefore antibiotics should have no effect on them. The hypothesis that was tested was that antibiotics decrease the yield of yeast cells. In general the materials that were used in this experiment were a clean hemacytometer, a pipette, a solution of yeast with no antibiotics (culture A), and a solution of yeast
Since saccharomyces cerevesiae is not a bacteria, antibiotics should have had no effect on it (Murray). However, saccharomyces cerevesiae is a type of fungi but it is used to make bread and beer. Unlike most fungi, saccharomyces cerevesiae does not cause diseases in plants and animals (Raven). Saccharomyces cerevesiae is also employed as a nutritional supplement because it controls high levels of B vitamins and because about 50% of yeast is protein (Raven). Antibiotics, also known as antibacterial agents, are used to destroy or slow down the growth of bacteria. They are mainly used to treat infections caused by bacteria. Bacteria are microscopic organisms which may cause illness. There are several types of antibiotics and the original known antibiotic is penicillin. Most antibiotics work by stopping the bacteria from multiplying (Nordqvist). When antibiotics were added to the yeast cells, some results showed a decrease in these cells. Since yeast is not a bacteria, a study was taken to explain this outcome. During this study, two types of cultures of yeast cells were tested, one contained an antibiotic and the other did not. The hypothesis that was tested was that antibiotics decrease the yield of yeast cells. However, the null hypothesis is that the addition of antibiotics to the yeast cultures would have had no effect on them. The null hypothesis is
Use a pipette to obtain a small sample of culture A, no antibiotic culture, and place it into the top notch of the hemacytometer. Do the same thing with culture B, antibiotic culture, but instead place it in the lower notch. Make sure the counting chamber does not flood, if it does clean the hemacytometer and start over. Once the samples are in the hemacytometer correctly, place a cover slip over the chamber. Place the hemacytometer on the stage of a microscope and locate the first quadrant. Use the 4X objective lens to locate the quadrant, and then switch to 10X to count the yeast cells. Count the yeast cells in all 16 squares of quadrant 1, and then repeat for quadrants 2, 3, and 4. Once the number of yeast cells are all recorded for culture A, do the same thing for culture B. Calculate the total of yeast cells in all 4 quadrants for culture A and find the average. Do the same thing for culture B. If this experiment was done with multiple groups, record the averages for those cultures as well. Once all the averages have been obtained, calculate the total average of all the group’s totals. This is known as the arithmetic mean and is calculate with the following equation: X= ΣXN. The answer obtained here will be used later on for calculating other equations. The next thing to be calculated is the variance (S²), which is used to help the variability in the