Gram Negative Bacteria Flashcards, test questions and answers
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What is Gram Negative Bacteria?
Gram Negative Bacteria are a group of bacteria that have an outer cell membrane and contain lipopolysaccharides. These bacteria can be found in many different environments, such as soil, water, and the human body. Gram-negative bacteria are typically more resistant to antibiotics than Gram-positive bacteria, making them challenging to treat. Gram-negative bacteria have a unique structure that is composed of two components: an inner cytoplasmic membrane and an outer cell wall. The inner membrane is made up of fatty acids and proteins which protect the bacterial cell from environmental changes. The outer wall contains a polysaccharide layer called lipopolysaccharides (LPS). This layer creates an additional barrier against antibiotics and other toxins that the organism may encounter in its environment. Gram-negative bacteria are very diverse, with some species being beneficial while others can cause serious illnesses in humans or animals. Some examples of pathogenic Gram-negative bacteria include Escherichia coli (E. coli), Salmonella spp., Shigella spp., Klebsiella pneumoniae and Pseudomonas aeruginosa. These organisms can cause food poisoning, urinary tract infections, pneumonia, sepsis and other diseases in humans or animals when they come into contact with someone’s body mucous membranes or bloodstreams. In addition to their role as pathogens, Gram negative bacteria also play important roles in nature through processes such as nitrogen fixation (which helps plants grow) and nutrient cycling (which recycles essential elements). They also help keep harmful pathogens at bay by competing for resources in their environment and producing toxins which kill off harmful organisms. Gram negative bacteria can be identified under the microscope by using a staining technique called the Gram stain.