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Bacteria- Microbiology Test 1

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General Info A. Ubiquitousness- something that’s e/w. Bac is all around us- air, water, soil, Arctic ice... B. Normal flora- refers to the many bacteria that live on us or in us 1. useful and necessary, usually harmless- non-pathogens 2. can become pathogens when: a. bac enters part of body that’s usually sterile- ex: blood, CSF b. compromised host- person’s immune system is weakened or knocked out 1. can be due to x-rays, chemo, AIDS C. Pathogens- disease-causing bac 1. “only” about 100-150 pathogens D. Roles of bac 1. dynamic organisms, grow and metabolize- make products that can be: a. good- ex: cheese, bread, and wine b. bad- ex: toxins cause disease E. Where do bac fit in larger scheme of life? Eukaryotes Prokaryotes Examples fungi algae protozoa plant man 1) archaea- found in hot springs, near geysers, deep sea vents in oceans, as normal flora in acidic gut 2) bacteria Nuclear membrane Yes No- have DNA, but not in nucleus Multiple chromosomes Yes No- single, circular chromosome Mitotic apparatus Yes No- do replicate genetic material. But no centrioles, centromeres, and spindle fibers. No prophase, metaphase...- mechanism for replication is different Mitochondria Yes No- have similar organelles that carry out electron transport and oxid phosph in cell membrane Ribosomes Yes- 80s Yes- 70s. S=Svedberg constant= operational unit referring to how ribosomes move in a centrifugal field= measure of size. Lysosomes, Golgi, ER Yes No. Lysosomes= mem bound organelle containing dig enzymes. No mem structures in prok. Steroids (in cell mem) Yes No- there is one genus of bac that has steroids (from cholesterol) in the cell membrane, but 99% don’t Cell Wall No- not humans Yes- There are antibodies that only target the cell wall, so will harm only bac, not ppl Muramic acid, Diaminopimelic acid No Yes- found in cell wall, so only found in bac, not humans Shayna Goodman -2- F. How do you tell one bac species from a/t? Diagnostic microbiology 1. differentiate using 7 characteristics a. morphology- shape, appearance of indiv cell and colony b. staining properties- can stain whole cell or part of cell c. motility- ability of some bac to swim through medium d. spore formation- protective, defensive form of bac e. oxygen requirement- either aerobic, anaerobic, or can grow either way f. carbon source utilization- dif bac use dif carbon sources to break down lipids, amino acids, and organic molecules g. biosynthetic products- bac make particular products/ molecules II. Morphology A. For cells- 3 shapes: 1. sphere- coccus a. diplo- pair (ex: diplococcus- 2 spherical cells attached) b. strepto- chain (ex: streptococcus- spherical cells attached in a chain) c. staphylo- cluster (ex: staphylococcus- cluster of spherical cells) 2. rod- bacillus (doesn’t have to be symmetrical- ex: pencil) 3. spiral- spirill

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