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52 Cards in this Set
- Front
- Back
aseptic technique
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handling microorganisms without
-infecting laboratory worker -contamination with extraneous ones. |
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bacterium
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Microorganism classified as procaryote because it lacks a true nucleus.
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colony
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visible population of cells growing on a solid medium and arising from a single cell.
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culture
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growth of microorganisms
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culture (verb)
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to place onto a medium for propagation of microorganisms
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fastidious
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difficult to grow
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medium
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substance or preparation containing essential nutrients for cultivation of living cells.
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microorganism
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seen only through microscop
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sepsis
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microorganisms present; infection
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Properties necessary for sustaining growth on a culture medium:
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Nutrients
Atmosphere pH Sterile Temperature |
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Nutrients required by medically important bacteria:
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Carbon
Nitrogen Inorganic salts of (Fe, Mg, Ph, K, S) Water Growth Factors |
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what growth factors may be needed by medically important bacteria?
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Blood
Calcium Sodium Carbs Vitamins Trace elements |
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What does Water do for culture media nutrients?
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provides source of hydrogen
helps transport of nutrients keeps culture medium fresh. |
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Proper atmosphere for aerobic bacterial growth:
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free flow of oxygen
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proper ph for bacteria
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6-8
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what happens in the lag phase?
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bacteria get accustomed to their environment; not so much increase in growth
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what happens in the logarithmic phase?
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a constant rate of growth;
doubling of bacterial population app. every half hour! |
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what happens in the stationary phase?
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bacterial population is constant with rate of growth = rate of death.
nutrient supply gets exhausted; toxed end products accumulate. |
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What happens in the phase of decline?
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death occurs at faster rate than multiplication.
colonies still present on medium, but some are not viable anymore. |
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Which phase do we look at bacteria in?
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18-24 hrs; stationary phase.
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3 types of culture media:
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liquid, semi-solid, solid.
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agar solidifies and liquifies at:
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45 and 98 celcius
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amount of agar in liquid media
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<0.1%
only in it to enhance growth |
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amount of agar in semi-solid media
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.3 - .5%
jelly-like medium for detection of bacterial motility. |
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amount of agar in solid medium
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minimum 1.5%
makes a plate, slant, or deep. |
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4 types of surface growth in a broth
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ring
pellicle flocculant membraneous |
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whats a pellicle in a broth?
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thick growth of organism extending across the surface of liquid
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3 types of subsurface growth in a broth
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turbid - cloudy
granular - small particles flocculant - small floating masses |
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two methods of colony isolation
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streak plate
pour plate - for counting numbers of colonies |
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heterotrophs vs. autotrophs
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hetero - utilize organic carbon sources.
auto - utilize inorganic carbon sources. |
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photo vs. chemoheterotrophs
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photo derive energy from sunlight
chemo from chemical reactions (what we study) |
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essential nutrients for culture medium
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carbon
nitrogen MACRONUTRIENTS: inorganic salts of Fe, Mg, P, K, S Water Oxygen Micronutrients: sheeps blood, NaCl, Carbohydrates |
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What micronutrients are used in culture medium, and for what purpose?
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NaCl, Carbs, and Sheeps blood.
To enhance growth of fastidious microorganisms. |
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Passive Transport
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nutrient transport along a concentration gradient (from high to low)
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3 types of passive transport
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Diffusion - high to low
Osmosis - diff of H2O Facilitated diffusion - diffusion via cell-membrane transport proteins, but still with tthe gradient. |
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2 energy-requiring transport
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-requires energy input
1. Active transport - nutrient binds to transport protein which brings it into the cell. 2. Group translocation - nutrient is chemically altered as it is transported into the cell. |
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2 aspects of bacterial growth to remember:
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-Growth curve
-Generation time |
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What is generation time?
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amt of time it takes to double a bacterial population. app 20-30 min
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How does a culture grow?
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by binary fission
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3 types of temp classifications
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Psychrophile
Mesophile Thermophile |
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Psychrophile
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loves cold
tolerates -5 to 30, best at 10-20 |
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Mesophile
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loves middle ground
tolerates 10-45 best at 37.5 |
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Psychrotolerant
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mesophile that tolerates cold temps.
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Thermophiles
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loves thermos - hot
Tolerates 30-80 best at 50-60. |
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3 types of Aerobes
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Obligate Aerobes
Microaerophiles Facultative Aerobes |
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Where do obligate aerobes grow and in what?
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At TOP of tube only; only in oxygen.
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Where do microaerophiles grow and in what?
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just below surface of tube; can't tolerate atmospheric O2, need lower levels.
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Where do facultative anaerobes grow, and in what?
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all over the tube! They like O2 best, but can tolerate lower levels or lack of it.
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2 types of anaerobes
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obligate anerobes
aerotolerant anaerobes |
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Where do obligate anaerobes grow and in what?
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Not in O2; only at bottom of tube.
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Where do aerotolerant anaerobes grow and in what?
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All over in a broth tube, but heaver at bottom because they prefer no O2. In O2 or none. A lot like facultative anaerobes, but they prefer no O2.
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What are capnophiles?
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CO2 loving. like 5-10% enriched medium.
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