Gram-Negative Bacteria Lab Report

Introduction:
Bacteria create an enormous domain of prokaryote microorganisms that are diverse and abundant in most habitats on Earth. In fact, bacterial cells drastically outnumber somatic cells just on the external part of the human body compared to somatic cells within the whole body of a single individual. Bacteria are found just about anywhere on earth and are usually alongside other microorganisms including: mold spores or yeast cells, creating some difficulty when trying to distinguish between the two. It is extremely important to be able to differentiate the bacteria from the other microorganisms. In this lab the goal is to identify an unknown bacterial species located in the biology building, so being able to differentiate the microorganisms …show more content…
The most important step in analyzing an unknown species of bacteria is to categorize it as Gram-positive or Gram-negative. Bacteria is made up of different chemical composition of cell walls, this allows for the gram test to classify between the two major types. Gram-positive bacteria has a thick layer of peptidoglycan located in the cell wall, while Gram-negative bacteria have a thin layer of peptidoglycan layer in the cell wall. The Gram test is a staining technique that can detect the peptidoglycan in the cell walls of bacteria. The Gram-positive bacteria cells retain a colored dye in it’s thick peptidoglycan wall and appear purple to blue in color. Gram-negative bacteria cells do not have a thick peptidoglycan layer and are not able to retain the violet dye. However, Gram-negative cells can pick up the safranin counterstain and appear red to pink in color. The Gram test must be done with great precision and skill which can make it difficult to carry out positive results. Thus, simpler tests have been designed to carry out this experiment and differentiate between Gram-positive and Gram-negative