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27 Cards in this Set
- Front
- Back
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efficiency of bacteria
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only synthesize what they need
building blocks synthesized in the amounts proportional to needs toxic intermediates DONT accumulate unnecessary enzymes not made grow at max rate allowed by environmental conditions |
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metabolic tasks necessary for growth of bacteria or human cells use similar paths
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entry mechanisms
catabolic reactions biosynthesis polymerization assembly |
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electron transport chain-PMF
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electrons pass through chain located in cytoplasmic membrane
protons ejected, creates gradient that can do work |
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generating energy (How?)
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substrate level phosphorylation-a phosphorylated intermediate is converted to a high energy phosphate bond which reacts with ADP to form ATP
chemiosmosis- PMF drives ATPase and generates ATP |
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bacterial entry mechanisms
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active transport-requires energy (atp and pmf)
group translocation- phosphorylation facilitated diffusion- metabolism of nutrients (less common) |
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bacterial reproduction
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grow to about twice their size
binary fission attaches at ORI and replicates in two directions |
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phases of growth
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lag
exponential (log) stationary death (log) |
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nutrition of bacteria
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all are heterotrophic(need preformed hydrocarbons)
some require only inorganic salts and source of nitrogen others require more complex media(vitamins, AA's, purines) those that require a very enriched medium to grow are termed fastidious |
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Fermentation vs. aerobic respiration
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lots more energy with aerobic respiration, therefore, lots more growth
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strict anaerobes
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respiration occurs through electron transport, oxygen is final acceptor
only oxygen environments |
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obligate anaerobes
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fermentation- terminal acceptor is is an organic metabolic intermediate --> organic acid (lactic acid)
oxygenless environments only |
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facultative
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bacteria grow aerobically in presence of oxygen and anaerobically in absence of oxygen
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aerotolerant
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tolerate oxygen but grow fermentatively
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iron is essential for bacterial growth
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bacteria secrete siderophores-iron chelating compounds
competitive advantage to get iron |
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synthesis of bacterial cell wall (peptidoglycan)
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uridine diphosphate (UDP) carrier activates N-acetyl muramic acid (NAM) and N-acetylglucosame (NAG)
pentapeptide is added to UDP-NAM UDP-NAM-PEP transfers to bactoprenol phosphate UDP-NAG transfers to NAM-PEP to complete the peptidoglycan (ppg) monomer bactoprenol phosphate transport ppg monomers across cell membrane autolysins break the glycosidic bonds of ppg and peptide cross linkages transglycosidase (TG) enzyme inserts and links ppg monomers into new ppg transpeptidase (TP) enzymes reform the peptide cross links |
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fosfomycin
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inhibits phosphoenopyruvate transferase and prevents formations of NAM
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cycloserine
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anologue of D-alpha, blocks addition of dipeptide to UDP-NAM
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bacitracin
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blocks dephosphorylation of bactoprenol phosphate, inhibits cell wall synthesis
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vancomycin
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blocks transglycosidase and cell wall formation
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Beta lactams
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blocks transpeptidase and cell wall formation
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linezolid
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initiating complex of ribosome cycle blocked
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tetracycline, aminoglycosides
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30S inhibitors
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macrolides, chloramphenicol
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50S inhibitors
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fluoroquinolones, metronidazole
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blocks DNA synthesis
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rifampin
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blocks RNA synthesis
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sulfonamides, trimethoprim
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folate antagonist
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polymyxins
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attacks cell wall, disrupts it
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