Glossary of MB I
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- aseptic technique
- handling microorganisms without
-infecting laboratory worker
-contamination with extraneous ones.
- Microorganism classified as procaryote because it lacks a true nucleus.
- visible population of cells growing on a solid medium and arising from a single cell.
- growth of microorganisms
- culture (verb)
- to place onto a medium for propagation of microorganisms
- difficult to grow
- substance or preparation containing essential nutrients for cultivation of living cells.
- seen only through microscop
- microorganisms present; infection
- Properties necessary for sustaining growth on a culture medium:
- Nutrients required by medically important bacteria:
Inorganic salts of (Fe, Mg, Ph, K, S)
- what growth factors may be needed by medically important bacteria?
- What does Water do for culture media nutrients?
- provides source of hydrogen
helps transport of nutrients
keeps culture medium fresh.
- Proper atmosphere for aerobic bacterial growth:
- free flow of oxygen
- proper ph for bacteria
- what happens in the lag phase?
- bacteria get accustomed to their environment; not so much increase in growth
- what happens in the logarithmic phase?
- a constant rate of growth;
doubling of bacterial population app. every half hour!
- what happens in the stationary phase?
- bacterial population is constant with rate of growth = rate of death.
nutrient supply gets exhausted; toxed end products accumulate.
- What happens in the phase of decline?
- death occurs at faster rate than multiplication.
colonies still present on medium, but some are not viable anymore.
- Which phase do we look at bacteria in?
- 18-24 hrs; stationary phase.
- 3 types of culture media:
- liquid, semi-solid, solid.
- agar solidifies and liquifies at:
- 45 and 98 celcius
- amount of agar in liquid media
only in it to enhance growth
- amount of agar in semi-solid media
- .3 - .5%
jelly-like medium for detection of bacterial motility.
- amount of agar in solid medium
- minimum 1.5%
makes a plate, slant, or deep.
- 4 types of surface growth in a broth
- whats a pellicle in a broth?
- thick growth of organism extending across the surface of liquid
- 3 types of subsurface growth in a broth
- turbid - cloudy
granular - small particles
flocculant - small floating masses
- two methods of colony isolation
- streak plate
pour plate - for counting numbers of colonies
- heterotrophs vs. autotrophs
- hetero - utilize organic carbon sources.
auto - utilize inorganic carbon sources.
- photo vs. chemoheterotrophs
- photo derive energy from sunlight
chemo from chemical reactions (what we study)
- essential nutrients for culture medium
MACRONUTRIENTS: inorganic salts of Fe, Mg, P, K, S
Micronutrients: sheeps blood, NaCl, Carbohydrates
- What micronutrients are used in culture medium, and for what purpose?
- NaCl, Carbs, and Sheeps blood.
To enhance growth of fastidious microorganisms.
- Passive Transport
- nutrient transport along a concentration gradient (from high to low)
- 3 types of passive transport
- Diffusion - high to low
Osmosis - diff of H2O
Facilitated diffusion - diffusion via cell-membrane transport proteins, but still with tthe gradient.
- 2 energy-requiring transport
- -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.
- 2 aspects of bacterial growth to remember:
- -Growth curve
- What is generation time?
- amt of time it takes to double a bacterial population. app 20-30 min
- How does a culture grow?
- by binary fission
- 3 types of temp classifications
- loves cold
tolerates -5 to 30, best at 10-20
- loves middle ground
best at 37.5
- mesophile that tolerates cold temps.
- loves thermos - hot
best at 50-60.
- 3 types of Aerobes
- Obligate Aerobes
- Where do obligate aerobes grow and in what?
- At TOP of tube only; only in oxygen.
- Where do microaerophiles grow and in what?
- just below surface of tube; can't tolerate atmospheric O2, need lower levels.
- Where do facultative anaerobes grow, and in what?
- all over the tube! They like O2 best, but can tolerate lower levels or lack of it.
- 2 types of anaerobes
- obligate anerobes
- Where do obligate anaerobes grow and in what?
- Not in O2; only at bottom of tube.
- Where do aerotolerant anaerobes grow and in what?
- 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.
- What are capnophiles?
- CO2 loving. like 5-10% enriched medium.
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