Microbiology Lab UTA – Final Exam
Questions with Solutions
How is Media made? - -5 g. T.S.A. and 125 mL Di water, cover flask with foil,
affix autoclave tape, autoclave, wait 10-20 min to cool, pour into petri-dish to
thickness of lid. or stop when covers bottom.
- Agar - -linear polysaccharide polymer derived from agarose in red algae.
- What does agar do? - -increases solidity, exhibits hysteresis- gels and
melts at different temps. Melts above 85-90 and solidifies at 40-45.
- What is liquid media? - -commonly called broths, doesn't contain agar,
easy to use, allows observation of growth patterns.
- Advantages to using semi-solid media - -To test oxygen requirements, to
test motility.
- Fastidious - -only grows in a fortified culture media under specific
conditions. The more _____________ the organism, the more specific
ingredients a medium must have. Uses defined media.
- Why use solid media? - -The maintenance and growth of stock cultures, to
isolate single colonies, to ensure purity.
- T.S.A. Plate - -Tryptic Soy Agar most common medium used in lab.
Undefined media that contains casein digest, soybean digest, NaCl, and
agar.
- What are the 4 biochemical families all living things are composed of? - -
Proteins, Carbohydrates, lipids, nucleic acids
- How much water does a bacteria cell consist of? - -70%
- Autoclave - -sterilizes with steam at 121* C, pressure at 15 PSI for at least
15 min. Tested weekly to daily.
- Reservoir - -potential source of infection.
- Normal commensal symbionts - -S. pneumoniae and s. aureus
- Environmentally acquired microbes - -p. aeruginosa and b. cepacia
, - Magnifications of our microscopes - -scanning: 4x-40, low: 10x-100, high:
40x-400, oil immersion: 100x-1000
- What is resolving power? - -How close two objects can be and still be
distinguished as separate.
- What is the optimum resolution of the microscope using oil immersion? -
-.2 micrometer.
- How much does each microscope cost? - -$1600
- convex - -Morphology of a domed colony
- raised - -flatter dome than convex
- flat elevation - -
- crateriform - -hole in convex colony
- Umbonate - -Morphology of a colony with a raised center
- Rhizoid - -Morphology of a branching colony
- lobate - -margin with lobes
- undilated margins - -irregular but not lobed
- curled - -wave pattern on margin
- entire margin - -even smooth all around
- Filiform Growth - -Agar slant. Colony exhibits a dense/opaque surface with
a defined edge.
- Friable Growth - -Agar slants. Colony exhibits crusty, irregular edges.
- Spreading edges - -motile organism
- Human error in inoculation - -What is responsible for most irregularities in
agar slants?
- Five I's - -inoculation, incubation, isolation, inspection, identification
- Flocculence - -Clumpy colonial aggregates seen in broth media.
streptococcus
Questions with Solutions
How is Media made? - -5 g. T.S.A. and 125 mL Di water, cover flask with foil,
affix autoclave tape, autoclave, wait 10-20 min to cool, pour into petri-dish to
thickness of lid. or stop when covers bottom.
- Agar - -linear polysaccharide polymer derived from agarose in red algae.
- What does agar do? - -increases solidity, exhibits hysteresis- gels and
melts at different temps. Melts above 85-90 and solidifies at 40-45.
- What is liquid media? - -commonly called broths, doesn't contain agar,
easy to use, allows observation of growth patterns.
- Advantages to using semi-solid media - -To test oxygen requirements, to
test motility.
- Fastidious - -only grows in a fortified culture media under specific
conditions. The more _____________ the organism, the more specific
ingredients a medium must have. Uses defined media.
- Why use solid media? - -The maintenance and growth of stock cultures, to
isolate single colonies, to ensure purity.
- T.S.A. Plate - -Tryptic Soy Agar most common medium used in lab.
Undefined media that contains casein digest, soybean digest, NaCl, and
agar.
- What are the 4 biochemical families all living things are composed of? - -
Proteins, Carbohydrates, lipids, nucleic acids
- How much water does a bacteria cell consist of? - -70%
- Autoclave - -sterilizes with steam at 121* C, pressure at 15 PSI for at least
15 min. Tested weekly to daily.
- Reservoir - -potential source of infection.
- Normal commensal symbionts - -S. pneumoniae and s. aureus
- Environmentally acquired microbes - -p. aeruginosa and b. cepacia
, - Magnifications of our microscopes - -scanning: 4x-40, low: 10x-100, high:
40x-400, oil immersion: 100x-1000
- What is resolving power? - -How close two objects can be and still be
distinguished as separate.
- What is the optimum resolution of the microscope using oil immersion? -
-.2 micrometer.
- How much does each microscope cost? - -$1600
- convex - -Morphology of a domed colony
- raised - -flatter dome than convex
- flat elevation - -
- crateriform - -hole in convex colony
- Umbonate - -Morphology of a colony with a raised center
- Rhizoid - -Morphology of a branching colony
- lobate - -margin with lobes
- undilated margins - -irregular but not lobed
- curled - -wave pattern on margin
- entire margin - -even smooth all around
- Filiform Growth - -Agar slant. Colony exhibits a dense/opaque surface with
a defined edge.
- Friable Growth - -Agar slants. Colony exhibits crusty, irregular edges.
- Spreading edges - -motile organism
- Human error in inoculation - -What is responsible for most irregularities in
agar slants?
- Five I's - -inoculation, incubation, isolation, inspection, identification
- Flocculence - -Clumpy colonial aggregates seen in broth media.
streptococcus
