TCU Microbiology Lab Exam 1
Questions and Answers 100% Pass
chemically defined (synthetic) media - ✔✔media composed of precisely defined
chemicals
elements that all bacteria need - ✔✔carbon, nitrogen, phosphorus, sulfur, oxygen, and
hydrogen
minimal media - ✔✔media that contains exact nutrients needed for growth and nothing
extra
- media is useful b/c we know exactly what's in it, but few organisms are resourceful
enough to survive with only a few salts and sugars
complex media - ✔✔- it contains all the nutrients necessary for the microbes
- aka general purpose media, satisfies the nutritional requirements of bacteria with
more stringent growth requirements
- consists of mix of digests & extracts from plant or animal tissue
- nutrient rich but poorly defined with the exact nutrients unknown
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,- in lab we use complex media: tryptic soy media
enriched media - ✔✔complex media that contains additional "special"
nutrients/additives that are not commonly found in media
- least commonly used media
autoclave - ✔✔media is subjected to high-pressure steam at 121C at 15 lbs. of pressure
to sterilize and destroy any contaminants present
two major forms of media - ✔✔liquid and solid media
- media solidifies by adding agar (1.5%)
- agar is inert and incapable of growing by itself
what temperature do most bacterial organisms grow at? - ✔✔37C (98.6F)
colony - ✔✔A population of cells arising from a bacterial cell group or from a group of
attached bacterial cells
colony forming units (cfu) - ✔✔estimate the approximate number of bacteria in a liquid
broth culture
simple microscope - ✔✔contains a single magnifying lens and is similar to a magnifying
lens
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, compound microscope - ✔✔consists of two singles lenses arranged one in front of the
other so that the second lens magnifies the image produced by the first
illuminator - ✔✔light emits from this
condenser - ✔✔light passes through this and concentrates the light and focuses the light
onto the specimen
parfocal - ✔✔property of a microscope which allows objectives to be changed with
minimal or no refocusing
total magnification - ✔✔objective magnification (4X, 10X, 40X, 100X) x ocular
magnification (10X)
working distance - ✔✔distance between the objective and the object being viewed
depth of focus - ✔✔thickness of specimen that can be seen in focus at one time
resolving power - ✔✔the ability of the microscope to distinguish between two closely
adjacent points; measured in distance units
refractive index - ✔✔measure of how much the speed of light is reduced inside a
medium such as glass; the refractive index of air and glass are different enough so that
light waves change direction when they cross the interface from air to glass. The
necessitates that use of immersion oil with our 100X oil-immersion oil.
aseptic technique - ✔✔transferring without causing contamination to the culture
Katelyn Whitman, All Rights Reserved © 2025 3
Questions and Answers 100% Pass
chemically defined (synthetic) media - ✔✔media composed of precisely defined
chemicals
elements that all bacteria need - ✔✔carbon, nitrogen, phosphorus, sulfur, oxygen, and
hydrogen
minimal media - ✔✔media that contains exact nutrients needed for growth and nothing
extra
- media is useful b/c we know exactly what's in it, but few organisms are resourceful
enough to survive with only a few salts and sugars
complex media - ✔✔- it contains all the nutrients necessary for the microbes
- aka general purpose media, satisfies the nutritional requirements of bacteria with
more stringent growth requirements
- consists of mix of digests & extracts from plant or animal tissue
- nutrient rich but poorly defined with the exact nutrients unknown
Katelyn Whitman, All Rights Reserved © 2025 1
,- in lab we use complex media: tryptic soy media
enriched media - ✔✔complex media that contains additional "special"
nutrients/additives that are not commonly found in media
- least commonly used media
autoclave - ✔✔media is subjected to high-pressure steam at 121C at 15 lbs. of pressure
to sterilize and destroy any contaminants present
two major forms of media - ✔✔liquid and solid media
- media solidifies by adding agar (1.5%)
- agar is inert and incapable of growing by itself
what temperature do most bacterial organisms grow at? - ✔✔37C (98.6F)
colony - ✔✔A population of cells arising from a bacterial cell group or from a group of
attached bacterial cells
colony forming units (cfu) - ✔✔estimate the approximate number of bacteria in a liquid
broth culture
simple microscope - ✔✔contains a single magnifying lens and is similar to a magnifying
lens
Katelyn Whitman, All Rights Reserved © 2025 2
, compound microscope - ✔✔consists of two singles lenses arranged one in front of the
other so that the second lens magnifies the image produced by the first
illuminator - ✔✔light emits from this
condenser - ✔✔light passes through this and concentrates the light and focuses the light
onto the specimen
parfocal - ✔✔property of a microscope which allows objectives to be changed with
minimal or no refocusing
total magnification - ✔✔objective magnification (4X, 10X, 40X, 100X) x ocular
magnification (10X)
working distance - ✔✔distance between the objective and the object being viewed
depth of focus - ✔✔thickness of specimen that can be seen in focus at one time
resolving power - ✔✔the ability of the microscope to distinguish between two closely
adjacent points; measured in distance units
refractive index - ✔✔measure of how much the speed of light is reduced inside a
medium such as glass; the refractive index of air and glass are different enough so that
light waves change direction when they cross the interface from air to glass. The
necessitates that use of immersion oil with our 100X oil-immersion oil.
aseptic technique - ✔✔transferring without causing contamination to the culture
Katelyn Whitman, All Rights Reserved © 2025 3
