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25 Cards in this Set
- Front
- Back
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minimum temperature |
below which no growth occurs, don't like |
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optimum temperature |
most suited for maximum growth, close to max temp |
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maximum temperature |
above which no growth occurs |
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psychophiles |
no disease living bac, -5C to 20C cold-loving |
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mesophiles |
pathogens- disease, 20C to 50C middle |
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thermophiles |
50C to 80C, not many pathogens |
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hyperthermophiles |
near boiling point, die if taken away from hot temp, not many pathogens temp in food industry and disease |
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psychotroph |
cold tolerant, 0C to 20C responsible for food spoiling |
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cell membrane function in solution |
guards against changes in osmotic pressure, keeps stable isotonic- ideal, body likes .85% NaCl inside hypertonic- draws H2O out, 10% NaCl |
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ph |
neutral (around 7) best neutrophiles- neutral, buffering system inside cell acidophiles- acidic alkaliphiles- basic H pylori- high tolerant, acidic, in individuals with ulcer, treat with antibiotics fungi- lower ph, pump out protons as quick as enter
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urease |
splits into ammonia and CO2, neutralize/ steady ph |
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osmotic pressure |
inside bac stable, no ammonia in stomach- works against osmotic pressure, cell membrane helps salts, sugars, nutrients dissolved in H2O (prevent microbial growth) |
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halophile |
salt loving, high Na content, die in neutral environment |
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facultative halophile |
can adapt to salt staphylococcus halotolerant- gastrococculus infection (24 hour bug) |
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obligate aerobes |
need oxygen(love it)- electron acceptor, affects areas of body with abundant oxygen humans |
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obligate anaerobes |
killed by oxygen (sensitive)- unable to detoxify some products of oxygen metabolism, can not use oxygen unless they have enzymes, proteins, mechanisms clostridium |
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facultative anaerobes |
grow more rapid in oxygen but can grow in presence/absence of oxygen, many can ferment (anaerobic respiration) E. Coli |
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microaerophiles |
use oxygen in low levels, some oxygen sensitive enzymes, cannot tolerate high levels of oxygen- limited respiration H pylori |
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aerotolerant anaerobes |
cannot use oxygen but grow in presence of it, obligate fermentors Streptococcus pyogenes |
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toxic products of oxygen |
singlet oxygen hydrogen peroxide- anti microbial reagent, neutralized by catalase, damage cell hydroxyl radical oxygen is electron acceptor |
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microbial growth cycle |
lag log stationary death |
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lag phase |
cell stabilizing (produce AA), no visible change, ready for cell division |
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log phase |
cells divide rapidly, steep rise in growth, produce primary metabolize (required)- AA, vitamins, nutrients binary fission- split of cells (not sex) glycolosis, krebs cycle (used over and over) |
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stationary phase |
begins to equalize, cells dying/multiplying stabilizes, exhaust nutrients produce secondary metabolize (not required)- antibiotics antibiotics- against light |
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death phase |
die off rapidly, no more resources |
