Bacteria F Lab Report

After part 1, the experimenters found two things about the Bacteria: First, that the bacterium was bacilli (rod) shaped. This was determined by viewing individual cells through a microscope at 400x power. Secondly, that the bacterium was most likely a Gram-stain-negative because it appeared to be a pink color after gram-staining. This had several implications: The experimenters now knew the bacteria’s cell wall composition, its outer membrane composition, peptidoglycan concentration, outer membrane amount, and more. Because of the gram stain results, it is evident that Bacteria F has a thin two-layer cell wall with an outer membrane and is on the small side of bacteria. At the end of the experiment, the experimenters were able to view the effectiveness of …show more content…
Kanamycin was expected to have the largest zone of inhibition but ended up with a diameter of 3.5 centimeters. Erythromycin was not expected to be the most effective but ended up with a zone of inhibition of 4 centimeters. On the other hand, Tetracycline had a zone of inhibition of 0.5 centimeters, and the control (just a disk of filler paper) had a 0-centimeter zone of inhibition. Qualitatively, the differences were obvious; Kanamycin and Erythromycin both had large circles surrounding the disk whereas the tetracycline had a very small zone of inhibition and the control had no zone of inhibition whatsoever. These results contrasted the hypothesis because Kanamycin was not the most effective. Instead, Erythromycin had a larger zone of inhibition, by 0.5 centimeters. A larger zone of inhibition correlates with a more effective antibiotic. Additionally, it was expected that Tetracycline would be more effective than it actually was. There are several potential reasons for the distinction from the aforementioned hypothesis. Firstly, the bacteria might have actually been Gram-positive. Erythromycin is most effective against Gram-positive bacteria, so this might explain why Erythromycin was the most effective