BIOL-2026EL Lecture Notes - Lecture 2: Deinococcus Radiodurans, Small Cell, Flagellin
4 Dec 2015
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Document Summary
Takes many different forms: spherical, rod, comma, spiral, pleiomorphic > varied shapes. Toughest bacterium in the world and commonly found in soils and foods. Can handle acute dose of 5, 000 gray units of ionizing radiation. Can be determined by selective forces: nutrient uptake efficiency, spirals allow efficient swimming in viscous or turbulent fluids, the gliding motility. Can also be multicellular organizations: hypae > branching filaments of cells, mycelia > tufts of hyphae, trichomes > smooth, unbranched chains of cells. >700 microm. in diameter: most rod bacteria are 0. 5-4. 0 micrometer wide and 1-15microm long, very small cells are found in marine environments. The minimum size is due to the minimum space requirements for genome, proteins, and ribosomes. Have a higher surface to volume ratio. Gives greater rate of nutrient and waste exchange per unit volume. Supports faster growth rate, and faster evolution. The largest region is the nucleoid region: houses many chromosomes and dna replication machinery.
