Introduction
Our world is composed of many bacteria that can either help or destroy us. Therefore, its’s imperative to learn and study them. The purpose of the lab was to put into action the methods learned in the laboratory to determine our unknown bacteria.
Bacteria can have different features, shapes, and or arrangements that help microbiologist differentiate them. Bacteria can be classified as Gram positive or negative (difference in cell wall), with the help of the Gam stain (“Gram Stain”, n. d). Another way to help differentiate a specific bacterium is to utilize biochemical tests. Biochemical test is used to indicate if the bacteria can metabolize a certain ingredient. For example, the phenol red broths are three different kind …show more content…
If the tube turns yellow after incubation then it indicates lactose/sucrose/glucose positive, depending in what tube. If the tube stays the same color then it will indicate lactose/sucrose/glucose negative. (“Phenol Red Broth”, n. d). The Litmus Milk tube is to indicate if a bacterium can metabolize lactose as a source of energy. If the tube turns pink after incubation then it indicates lactose positive, but if the tube turns dark purple then its lactose negative (“Litmus Milk”, n. d). However, some more methods or test are SIM, MRVP, TSI, Nitrate Test, starch, gelatin, citrate, urea, oxidase, and catalase that all check for different thing in a bacterium. Although bacteria can have different cell structures and or ferment/metabolize different components, they also have specific shape and arrangements that can be helpful when determining a bacterium. The most common shapes are coccus (round), bacillus (rod-shape), and spiral (squiggly line). The shape can be accompanied by a …show more content…
Two unknown bacteria where handed out by the lab instructor in one tub on the date February 27. In the same date, the Gram stain and isolation streak method was performed. The gram stain was performed to differentiate between gram positive and negative cell wall on my bacteria’s (“Gram Stain”, n.d). In the gram stain, having a fixed slide already, a drop of crystal violet was added about a minute. Later, water was used to rinse the slide, and a drop of grams’ iodine was added about a minute. These steps stained the slide purple. Later, discoloration was achieved with alcohol about ten to fifteen seconds. Final step, a drop of safranin was added about one minute and water was used to rinse the slide. Gram positive will stain purple and gram negative will stain pink. In addition, the morphology and arrangement was detected when viewing the gram stain on my bacteria. After knowing the shape and differentiating my two bacteria form Gram positive and negative, an isolation streak method was utilized to isolate the two different bacteria. This was achieved by first, obtaining a small amount of bacteria on the loop and making a first quadrant on the TSI agar plate. Second, with a sterile loop a second quadrant was made. Lastly, again with a sterile loop a third quadrant was achieved. Then it was put into incubation, so
Our world is composed of many bacteria that can either help or destroy us. Therefore, its’s imperative to learn and study them. The purpose of the lab was to put into action the methods learned in the laboratory to determine our unknown bacteria.
Bacteria can have different features, shapes, and or arrangements that help microbiologist differentiate them. Bacteria can be classified as Gram positive or negative (difference in cell wall), with the help of the Gam stain (“Gram Stain”, n. d). Another way to help differentiate a specific bacterium is to utilize biochemical tests. Biochemical test is used to indicate if the bacteria can metabolize a certain ingredient. For example, the phenol red broths are three different kind …show more content…
If the tube turns yellow after incubation then it indicates lactose/sucrose/glucose positive, depending in what tube. If the tube stays the same color then it will indicate lactose/sucrose/glucose negative. (“Phenol Red Broth”, n. d). The Litmus Milk tube is to indicate if a bacterium can metabolize lactose as a source of energy. If the tube turns pink after incubation then it indicates lactose positive, but if the tube turns dark purple then its lactose negative (“Litmus Milk”, n. d). However, some more methods or test are SIM, MRVP, TSI, Nitrate Test, starch, gelatin, citrate, urea, oxidase, and catalase that all check for different thing in a bacterium. Although bacteria can have different cell structures and or ferment/metabolize different components, they also have specific shape and arrangements that can be helpful when determining a bacterium. The most common shapes are coccus (round), bacillus (rod-shape), and spiral (squiggly line). The shape can be accompanied by a …show more content…
Two unknown bacteria where handed out by the lab instructor in one tub on the date February 27. In the same date, the Gram stain and isolation streak method was performed. The gram stain was performed to differentiate between gram positive and negative cell wall on my bacteria’s (“Gram Stain”, n.d). In the gram stain, having a fixed slide already, a drop of crystal violet was added about a minute. Later, water was used to rinse the slide, and a drop of grams’ iodine was added about a minute. These steps stained the slide purple. Later, discoloration was achieved with alcohol about ten to fifteen seconds. Final step, a drop of safranin was added about one minute and water was used to rinse the slide. Gram positive will stain purple and gram negative will stain pink. In addition, the morphology and arrangement was detected when viewing the gram stain on my bacteria. After knowing the shape and differentiating my two bacteria form Gram positive and negative, an isolation streak method was utilized to isolate the two different bacteria. This was achieved by first, obtaining a small amount of bacteria on the loop and making a first quadrant on the TSI agar plate. Second, with a sterile loop a second quadrant was made. Lastly, again with a sterile loop a third quadrant was achieved. Then it was put into incubation, so