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52 Cards in this Set

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aseptic technique
handling microorganisms without
-infecting laboratory worker
-contamination with extraneous ones.
bacterium
Microorganism classified as procaryote because it lacks a true nucleus.
colony
visible population of cells growing on a solid medium and arising from a single cell.
culture
growth of microorganisms
culture (verb)
to place onto a medium for propagation of microorganisms
fastidious
difficult to grow
medium
substance or preparation containing essential nutrients for cultivation of living cells.
microorganism
seen only through microscop
sepsis
microorganisms present; infection
Properties necessary for sustaining growth on a culture medium:
Nutrients
Atmosphere
pH
Sterile
Temperature
Nutrients required by medically important bacteria:
Carbon
Nitrogen
Inorganic salts of (Fe, Mg, Ph, K, S)
Water
Growth Factors
what growth factors may be needed by medically important bacteria?
Blood
Calcium
Sodium
Carbs
Vitamins
Trace elements
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
6-8
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
<0.1%
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
ring
pellicle
flocculant
membraneous
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
carbon
nitrogen
MACRONUTRIENTS: inorganic salts of Fe, Mg, P, K, S
Water
Oxygen
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
-Generation time
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
Psychrophile
Mesophile
Thermophile
Psychrophile
loves cold
tolerates -5 to 30, best at 10-20
Mesophile
loves middle ground
tolerates 10-45
best at 37.5
Psychrotolerant
mesophile that tolerates cold temps.
Thermophiles
loves thermos - hot
Tolerates 30-80
best at 50-60.
3 types of Aerobes
Obligate Aerobes
Microaerophiles
Facultative 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
aerotolerant anaerobes
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.