Surname 1DiscussionThe grain staining test was used to differentiate large groups of bacteria based on their different cell wall constituents. This procedure distinguished between Gram-negative and Gram-positive by coloring the cells violet or red. The presence of a thick layer of peptidoglycan in the cell wallsof the Gram-positive bacteria made them stain violet, hence retaining the crystal violet these cells were stained with. This is a clear indication of the presence of Gram-positive cells since they do not decolorize with ethanol and usually appear blue to purple. Since the unknown number fourteen were identified as Gram-positive Cocci, all Gram-positive rods and Gram-negative cocci were eliminated.The catalase test was used to differentiate staphylococci from streptococci. The presence of the enzyme was realized when a rapid elaboration of oxygen bubbles were observed after a small inoculum was introduced into hydrogen peroxide. This was due to the fact that bacteria usually
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- Fall '12
- Bacteria, J. Howard