A. Describe the four classes of flagellar arrangement common in microbes.
Many motile bacteria have thread-like appendages that extend out from the cell wall and allow them to move. These appendages are called flagellum and it moves the organism away from unfavorable environments. Most cocci bacteria are non-motile i.e. have no flagella. The range of motility and the number and distribution of flagella in bacteria are important characteristics that are used to identify and classify them. Each class of flagella has a distinct number of flagella and its location on the bacteria is unique to each class (Estridge, Reynolds, & Walters, 2007). First is the Monotrichous class. This class has a single polar, arising from one or both ends of the cell such as the Vibro Cholerae bacteria. Next there is the Amphitricous class. This class has one flagellum at both ends of the bacteria. An example of this class is the rhodospirillum rubrum . The third class is the lophtrichous, which is the class of bacteria that has a tuft i.e. several flagella at one or both ends of the bacteria. For example, helicobacter pylori. The fourth class is the peritrichous which has flagella surrounding all around the cell of the bacterium such as the bacillus brevis, proteus vulgaris and Escherichia coli does (Estridge, Reynolds, & Walters, 2007). B. Explain the purpose of inoculating with a needle instead of a loop in the motility test. An inoculating loop is used to transfer specimen in a liquid medium or plating. The inoculating needle is used to transfer the specimen to the soft agar medium. Using a needle to inoculate a motility tube creates a sharp and well defined stab line. This allows for growth to move along the stab line to become visible which indicates that the specimen is non-motile and if bacterial growth can be observed away from the line of the stab,