Microbiology and Immunology 2500A/B Lecture 8: McCormick_1-8
13 Oct 2016
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Document Summary
Three domains: eukarya, archaea and bacteria there are no pathogens in the archaea domain. But both archaea and bacteria make up the prokaryotes. Prokaryotes are the smallest, simplest and most abundant form of life on earth (the idea of viruses being alive or not is debated even still). They lack nuclei or similar complex organelles other than the cell membrane, there are no intracellular membrane-bound organelles in prokaryotes. Allows more nutrient exchange, faster growth and more frequent replication: bacteria evolve more quickly. Haploid genome (one set of chromosomes) has effective mutations more often. Bacteria reproduce by binary fission; resulting daughter cells are identical to parent cell. Generation time (doubling time): time for one generation to pass. Different bacterial species have different generation times some double in 10 mins (fast) while others take 24 hours (slow) Classification by shape: coccus (round), rod, and spirillum (worm-like) Obligate aerobes: must grow in oxygenated environments for growth.
