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22 Cards in this Set
- Front
- Back
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gram positive
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cell wall - 2 cell layers
thick peptidoglycan layer, extensive crosslinking, contains teichoic acid 6 classic types: 2 cocci, 4 rod shaped |
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gram negative
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cell wall - 3 layers
thin peptidoglycan layer, simple crosslinking unique outer cell membrane - two layers of phospholipids, outermost portion contains lipopolysaccharides and porin proteins mostly rod or pleomorphic except: neisseria diplococcus and s |
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lipopolysaccharides
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found in gram negative cell wall
3 covalently linked componentsouter carbo chains of 1-50 oligosaccharides core polysaccharide (center part) lipid A - interior to core polysaccharide (toxic to humans = gram neg. endotoxin) |
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transpeptidase
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penicillin binding protein
catalyzes cell wall crosslinking |
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obligate aerobes
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use glycolysis, TCA, e transport
have all 3 enzymes to breakdown harmful oxygen products: catalase, peroxidase, superoxide dismutase |
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facultative anaerobes
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aerobic! able to grow in absence of O2
use fermentation for energy |
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microaerophilic bacteria
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use fermentation and have no electron transport system
can tolerate low amounts of oxygen have superoxide dismutase |
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obligate anaerobes
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possess NO enzymes to defend against oxygen
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flagella
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virulence factor for movement
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pili
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virulence factor for adhesion
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capsule
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enable bacteria to be more virulent b/c macrophages and neutrophils are unable to phagocytize the encapsulated bacteria
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endospores
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formed only by bacillus and clostridium
metabolically dormant forms of bacteria that resist heat, cold, drying, and chemical agents form when nutrient shortage can lie dormant for years |
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facultative intracellular organisms
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inhibit phagosome - lysosome fusion, escaping hosts H2O2 and superoxide radicals
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exotoxins
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released by both gram - and +
neurotoxins - act on nn. and endplates to cause paralysis enterotoxin - act on GI tract and cause diarrhea pyrogenic exotoxin - stimulate cytokine release, rash, fever, toxic shock syndrome tissue invasion exotoxins |
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endotoxins
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lipid A (gram neg.)
released when bacterial cell undergoes lysis and steadily shed in living bacteria |
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bacterial chromosome
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dsDNA
haploid state giant loop no nuclear membrane surrounding DNA |
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bacterial replication
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form exact copy
split in two |
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genetic exchange
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transformation
transduction conjugation transposon insertions |
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transformation
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DNA fragment from lysis of one bacterium bind cell wall of another "competent" bacterium recipient
DNA take up intracellularly and can incorporate into recipient genome |
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transduction
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requires a bacteriophage
generalized and specialized bacterial DNA gets packaged in phage and inserted into different bacterium |
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conjugation
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DNA transferred by cell-to-cell contact
one bacteria must have F plasmid encodes enzymes and proteins necessary, including sex pilus |
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transposons
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mobile genetic elements that can insert themselves into a donor chromosome w/o DNA homology
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