Bio 211 Phenomenology Lab Report

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BIOL 211 Microbiology Lab May 7, 2014 Introduction In order for an individual to receive treatment for a certain bacterium, this bacterium must first be identified. This is done because some treatments may fight against one bacterium, while another treatment may not work to fight off a different bacterium. The purpose for this study is for the bacterium to be identified, in this case bacterium #67. This will be determined through a series of tests that vary based on the results of the previous test that we have learned in lab this semester. Procedure To determine the unknown sample of bacterium a gram stain was performed. This was done to determine if the bacteria was gram positive or gram negative. It also helped…show more content…
Based on the information from the gram stain, the unknown bacterium was a gram positive. This meant that the next step was a catalase test. A catalase test is done to identify organisms that produce the enzyme catalase and converts hydrogen peroxide into water and gaseous oxygen (1). A catalase test is used to separate staphs from streps in gram-positive cocci. For a catalase test, the bacterium must be placed onto a blood agar plate. This is done by aseptically transferring a loop full of the unknown broth bacterium onto the blood agar plate and incubated for about 24 hours. Once this is achieved the bacterium from the blood agar plate is used. To perform a catalase test first sterilize the inoculating loop with the Bunsen burner. Second, aseptically get an isolated colony of the unknown from the blood agar plate with the inoculating loop. Then, spread the bacteria onto the slide. Place one drop of hydrogen peroxide on top of the bacteria onto the slide. If the bacterium is catalase positive, then oxygen gas bubbles form immediately. If the bacterium is catalase negative, then no bubbles appear. In this lab the bacteria bubbled immediately, indicating a positive

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