Biochemical Unknown Lab
I. Introduction Cultural Characteristics or morphology and biochemical tests can be used to identify and classify microorganism. By culturing microorganism in nutrient broth, slants, and on nutrient agar plates, the cultural characteristics or morphology can be determined. In this lab, the test tube 2 was incubated in a nutrient broth. The pigmentation of the tube was yellow. The media for test tube 2 was turbid. There were a few sediment on the bottom of the broth. In addition, the tube 2 have pellicle, a layering of growth, of cells at the top. In this lab, the main purpose of this experiment is to identify the biochemical characteristics of an unknown bacteria by using first the Gram Stain and based on the results of the gram staining, several biochemical tests can be performed to identify with accuracy the unknown bacteria.
II. Identification Bacteria are divided into Gram Positive and Gram Negative based on the chemical composition of the cell wall. Gram stain, a differential stain, can be used to identify the shape, arrangement, and chemical composition of the microorganisms. In the chemical composition of the Gram stain, we can identify the two types of bacteria: Gram-Negative Bacteria which has a thin peptidoglycan, lipopolysaccharide, phospholipid, and lipoprotein cell wall and the Gram-Positive Bacteria which has a thicker peptidoglycan cell. When the microorganism appears purple (primary dye) and you follow all the instructions correctly, you will have a gram-positive