L and p rings seem to serve as bearings fimbria l

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- L, and P Rings seem to serve as Bearings Fimbria (L= fingers) and Pili (L= hairs) • Short, Hair-like Appendages - Composed of helically arranged Protein - Aid in Attachment to Surfaces (or to other Bacteria) Fimbria and Pili are structurally similar. Pili tend to be longer Fimbria tend to be important Pathogenicity Factors. A Bacterium usually needs to attach itself to some Portion of the Body -- say, your Urethra -- before it can cause any Mischief.
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Structure of Bacteria Page 8 Heterocysts (G= different cell) • Heterocysts are “different-looking” Cells in Filamentous Cyanobacteria that are specialized for Nitrogen Fixation - Nitrogen Fixation is the Conversion of Atmospheric Nitrogen (N 2 ) to Ammonia (NH 3 ) Nitrogen is a major component of Proteins, Nucleic Acids, and Coenzymes. Only Prokaryotes can utilize atmospheric Nitrogen by reducing it (“fixing it”) to Ammonia. This extremely important Reaction is catalyzed by the Enzyme Nitrogenase, which due to its Oxygen Sensitivity, is generally -- but not always -- sequestered in Heterocysts. Some Cyanobacteria employ a “Time Share” Scheme whereby Nitrogen Fixation and Photosynthesis occur in the same Cell but at different Times. • Nitrogen Fixation involves the Oxygen-Sensitive Enzyme Nitrogenase So Heterocysts lack Photosystem II (P680), have unusually thick Cell Walls and have Intercellular Connections with Adjacent Cells in the Filament. As a Result there ʼ s no Oxygen released via Hydrolysis. Environmental Oxygen (and all the Oxygen produced by Non-Heterocyst Cells in the Filament) is excluded. • NH 3 (Ammonia) is exported to adjacent Cells - Photosynthetic Products are imported from adjacent Cells Endospores ( G= inside seed) • Endospores (Spores) are resistant, dormant Structures found in some Gram Positive Bacteria (and only in Gram Positive Bacteria) - Spores are Characteristic of Bacillus and Clostridium • Spores are highly Resistant Structures - Resist Heat, UV, Chemical Disinfectants, Desiccation - Can last for a very long Time (possibly Millions of Years) • Spores have important Medical and Industrial Implications - Pose serious Contamination and Sepsis Problems Bacillus , Clostridium and a few other Gram Positive Bacteria -- mostly Soil-Dwellers like Heliobacter and Sporosarcina -- produce Endospores which are capable of surviving Environmental Extremes for amaziating Periods of Time. Spores removed from the Gut of a Bee suspended in Amber estimated to be 25-40 Million Years old and the Spores of a Halophilic Bacterium from Fluid Inclusions in Salt Crystals estimated to be 250 Million Years old have been germinated.
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