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92 Cards in this Set
- Front
- Back
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Do microbes increase in size or number during growth? |
Number only |
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Why is control of microbial growth important? |
infection control & growth of industrial and biotech organisms |
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What are the 3 factors that regulate growth? |
1. Nutrients 2. Environmental conditions: temperature, pH, osmotic pressure 3. Generation time |
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Chemical requirements: Elements |
C, H, O, P, S, N |
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Chemical requirements: Organic |
Glucose, Vitamins, Some Amino Acids (Purines/Pyrimidines) |
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Main chemical requirement |
Water |
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Nutritional Categories: Carbon source is CO2 = |
Autotroph |
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Nutritional Categories: Carbon source is organic = |
Heterotroph |
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Nutritional Categories: Energy source is sunlight = |
Phototroph |
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Nutritional Categories: Energy source is organic = |
Chemotroph |
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Nutritional Categories: Chemoorganic autotrophs |
Use organic molecules for energy Use inorganic molecules for carbon (CO2 ) |
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Lithotrophs |
Use inorganic molecules for energy Use inorganic molecules for carbon as well Important in deep sea life |
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A Saprobe... |
Lives on organic matter of dead organisms (Decomposers) |
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A Parasite... |
Lives on organic matter of living host = pathogens |
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Isotonic: |
same solutes inside and outside, no water movement |
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Hypotonic: |
more solutes inside, water enters cell |
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Hypertonic: |
more solutes outside, water leaves cell |
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Passive diffusion: |
osmosis |
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Facilitated diffusion: |
higher to lower concentration, carrier molecule |
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Active transport: |
lower to higher, takes energy |
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Group translocation: |
lower to higher with chemical change |
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Bulk transport: |
endocytosis, phagocytosis, pinocytosis |
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5 Environmental Factors Influencing Growth are... |
1. Temperature 2. O2 3. pH 4. Osmotic Pressure 5. Others: radiation, atmospheric pressure |
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Temperature: Which microbes love cold? |
Psychrophiles |
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Temperature: Which microbes love moderate temps? |
Mesophiles |
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Temperature: Which microbes love heat? |
Thermophiles |
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Optimum growth temperature is usually near... |
...the top of the growth range |
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Death above the maximum temp comes from... |
...enzyme inactivation |
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Temp Optima: What is the most common group? |
Mesophiles |
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At what low temp does growth slow or stop? |
40ºF (5°C) slows or stops growth of most microbes |
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Which microbes require Oxygen to live? |
Obligate aerobes |
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Which microbes can use Oxygen but also grow without it? |
Facultative anaerobes |
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Which microbes die in the presence of Oxygen? |
Obligate anaerobes |
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Which microbes do not use O2 but can grow when it is present? |
Aerotolerant |
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Which microbes require O2 but grow only in concentrations lower than air? |
Microaerophiles |
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Which microbes prefer higher CO2 concentrations (5-10%) |
Capnophiles |
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What does thioglycolate broth do/indicate? |
Oxygen tolerance |
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What does a brewers jar do? |
Used in the laboratory to create an anaerobic environment |
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What does a candle jar do? |
Used to create a microaerophilic and capnophilic environment |
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What are the 4 toxic forms of Oxygen? |
1. Singlet Oxygen 2. Superoxide Free Radicals 3. Peroxide anions 4. Hydroxyl radical |
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What is the pH range for most bacterial growth? |
6.5 to 7.5 |
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Which microbes can live at low pH? |
Acidophiles |
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What percent water are bacteria? |
80-90% |
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What does high salt in surrounding environment do to bacteria? |
Water loss and plasmolysis. Cell membrane shrinks, cell growth inhibited. |
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Preservation through high osmolarity includes... |
Salted fish, honey, jerky, condensed milk |
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What does hypotonic media (low osmolarity) do to bacteria without cell walls? |
Bacteria may lyse (pop) |
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Nutritional relationship where both benefit |
Mutualism |
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Nutritional relationship where microbe benefits and host is unharmed |
Commensalism |
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Nutritional relationship where microbe benefits, host is harmed |
Parasitism |
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How do bacteria divide |
Binary fission |
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Alternative means of bacterial division (3) |
Budding, conidiospores, fragmenatation |
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What is generation time? |
Time required for cell division/population to double. |
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What is average generation time for bacteria? |
1 to 3 hours |
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What happens during lag phase? |
Bacteria make new enzymes in response to new medium |
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What happens during log phase? |
Exponential growth. Desired for production of products. Most sensitive to drugs and radiation. |
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What happens during stationary phase? |
nutrients becoming limiting or waste products becoming toxic death rate = division rate |
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What happens during death phase? |
Death exceeds division |
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What are the direct methods for measuring growth? (count individual cells) |
Hemocytometer & Plating |
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What are the direct methods for measuring growth? (measure effects of bacterial cell growth) |
Turbidity – spectrophotometer Enzymatic activities |
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Measuring metabolic activity |
CO2 emission |
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Measuring growth: Dry weight |
weigh the specimin |
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What do selective media do? |
Selects for one type of bacteria over another |
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What can selective media select for? |
Gram stain, biochemical, antibiotic sensitivity |
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What do differential media do? |
Make different bacteria look different in a plate (biochemical) |
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What can turn different colors in differntial media? |
Colonies or the media itself |
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Media can be both... |
selective and differential |
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MSA Media... |
Selective: High salt (halophiles) Differential: (no ferment of manitol leaves media red/ferment=yello) |
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Pure culture method |
Streak for isolation |
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Antisepsis |
Reduction in the number of pathenognic microorganisms and viruses on living tissue |
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Aseptic |
Refers to an environment or procedure free of pathogenic contaminants |
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-cide / -cidal |
suffixes indicating destruction of a type of microbe |
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degerming |
removal of microbes by mechanical means |
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disinfection |
destruction of most microorganisms and viruses on nonliving tissue |
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pasteurization |
use of heat to destroy pathogens and reduce the number of spoilage microorganisms in foods and beverages |
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sanitization |
removal of pathogens from objects to meet public health standards |
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-stasis . -static |
Suffixes indicating inhibition, but not complete destruction, of a type of microbe |
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sterilization |
destruction of all microorganisms on an object |
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What are the most death resistant microbes |
Spores, thick lipid coated, protozoan cysts |
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What is the most sensitive to chemical body microbe? |
Enveloped virus |
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What is the least sensitive to chemical body microbe? |
Prions |
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What is thermal death time? |
How long it takes to kill a bacteria at a certain temperature |
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Pasteurization is used on products that need to keep taste unaffected. How long at what temp? |
30 min / 63 Celsius |
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What is temp and duration for UHT sterilization |
160 Celsius for 1-3 seconds |
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How does moist heat kill microbes? |
Coagulates proteins by breaking hydrogen bonds |
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Name two moist heat methods for killing pathogens |
Bioling and Autoclave |
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How long to boil? |
10 min kills most, not all |
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What temp and time for autoclave? |
15 psi for 15 min at 121 C |
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What cant be killed with dry heat |
Spores |
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What temp and time for dry heat? |
170 C for 2 hrs |
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What does psycrotolerant mean? |
Resistant to cold |
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Oxidizing agents... |
interfere with metabolism esp. anaerobes |
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Gas sterilization is used when object is |
sensitive to heat or moisture |
