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Practical 1 Flashcards

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1
Q

what does it mean that microorganisms are ubiquitous

A

found in any environmental condition

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2
Q

what is a pure culture

A

culture containing a single unadulterated species

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3
Q

what does survival and continued growth of microorganisms require

A

nutrients and a favourable growth environment

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4
Q

what is a culture medium

A

soluble low molecular weight substances (derived from enzymatic degredation of complex nutrients)

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5
Q

what is agar

A

used for solid media, extract of seaweed, is a complex carbohydrate composed mainly of galactose

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6
Q

why is agar a good solidfying agent

A

liquid at 100c and solid at 40c

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7
Q

what percent of agar is needed to have a solid media

A

1.5-1.8 percent

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8
Q

what is the main advantage to using agar slants in test tubes

A

best for maintaining pure cultures

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9
Q

whats the purpose of agar deep tubes

A

used for the study of gaseous requirements of microorganisms

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10
Q

what is the purpose of agar plates

A

large surface areas for the isolation and study of microorganisms

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11
Q

what is sterilization

A

process of rendering a medium or material free of all forms of life

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12
Q

what is the main function of aseptic technique

A

maintaining sterile where necessary and avoid external contamination

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13
Q

where can you use broth mediums

A

only in test tubes, never in petri dishes

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14
Q

what is a way to maintain aseptic technique in mediums

A

plastic lids in petri plates, metal or plastic caps in test tubes (historically cotton plugs)

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15
Q

how must petri dishes be incubated and why

A

incubated inverted (larger cap down) to prevent condensation from dripping

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16
Q

what is subculturing

A

microorganisms being transferred from one vessel to another

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17
Q

what are wire loops made of

A

inert metals such as nichrome or platinum

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18
Q

what is the function of an incubator

A

maintains a temperature for the microorganisms that is optimal for their growth

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19
Q

what is the function of a fridge

A

will slow or stop the growth of most microorganisms to be able to use for example as stock cultures

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20
Q

how do you transfer microorganisms from a tube to a petri plate

A

flame loop, remove cap, flame neck of tube, collect sample, flame neck of tube, cap, open petri plate, spread sample, lid petri plate, flame loop

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21
Q

what is one of the best ways to get a pure culture from a mixed culture

A

streak plate

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22
Q

what is a colony

A

individual macroscopically visible masses of microbial growth on solid medium representing replication of single microorganism

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23
Q

what is a streak plate

A

essentially a dilution series on solid media

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24
Q

what is colony morphology

A

visible collection of microorganism cells growing on the surface of solidified media

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25
for agar slants what are the terms for abundance of growth
none, slight, moderate, large
26
for agar slants what are the terms for optical characteristics
opaque, translucent, transparent
27
for agar slants what are the form types
filiform, echinulate, beaded, effuse, arborescent, rhizoid
28
what is filiform growth
continuous threadlike growth with smooth edges
29
what is echinulate growth
continuous threadlike growth with irregular edges
30
what is beaded growth
nonconfluent to semiconfluent colonies
31
what is effuse growth
thin spreading growth
32
what is arborescent growth
treelike growth
33
what is rhizoid growth
root like growth
34
what are the consistencies for agar slants
dry, buttery, mucoid
35
for agar plates what are the form types
circular, irregular, rhizoid
36
what are the margin types for agar plates
entire, lobate, undulate, serrate, filamentous
37
what is entire for agar plates
sharply defined and even
38
what is lobate for agar plates
marked indentations
39
what is undulate in agar plates
wavy indentations
40
what is filamentous in agar plates
threadlike spreading edge
41
what are the elevation types in agar plates
flat, raised, convex, umbonate
42
what is umbonate in agar plates
raised with an elevated convex central region
43
who pretty well invented the microscope
leeuwenhoek
44
what are the present day microscope magnification capabilities
greater than 250,000X
45
what are the two basic types of microscopes
light or electron
46
what are the types of light microscopes
brightfield, darkfield, phase-contrast, fluorescent
47
what kind of microscope uses uv light
fluorescence
48
how do electron microscopes work
electron beams and magnets to observe submicroscopic particles
49
what are the essential features of a brightfield microscope
2 lens system, tungsten light, specimen appears dark against a bright background, no contrast, good for stained slides not for living cells
50
what are the essential features of a darkfield microscope
condenser system modified so specimen isnt directly illuminated, specimen appears bright on a dark background, can observe living cells better than brightfield
51
what are the essential features of phase contrast microscope
can observe in unstained state, specimen appears dark against a bright background, light refracts to show structures of organism
52
what are the essential features of a fluorescent microscope
see organisms tagged with fluorescent dyes, uv light for illumination, used for antigen-antibody interactions, colour on black background
53
what are the essential features of an electron microscope
magnification up to 1 million x, illuminated by beam of electrons, focusing is done by electromagnets instead of optics, scanning for surface images, transmission for thin filaments
54
what is the stage of a microscope
fixed platform with opening for light passage, typically mechanical and can be moved horizontally and vertically
55
what is the abbe condenser
directly under the stage and has two sets of lenses to collect and concentrate light, also contains an iris diaphragm to regulate the amount of light
56
what is the body tube
above the stage and attached to arm of microscope, houses lens system to magnify specimen, body tube is lowered and raised by the adjustment knobs
57
how do you manipulate magnification
occular lens and objective lens
58
what is numerical aperture
function of the diameter of the objective lens in relation to its focal length
59
the ____ the wavelength the ___ the resolving power
the shorter the wavelength the greater the resolving power
60
____ wavelengths for ___ resolution
short wavelengths for better resolution
61
what is resolving power dependent on
refractive index and wavelength
62
what is the refractive index
bending power of light passing through air from the glass slide to the objective lens
63
what is the correct setup for koehler illumination
eye and specimen focused, specimen and field stop focused
64
what is the function of koehler illumination
illuminate specimen on slide, as light passes through specimen it should be parallel and evenly illuminated--its the best image you can get
65
what does it mean that a substage condenser uses a 2 conjugate plane system
if one is at focus the other is completely defocused but completely parallel
66
what are the two parts to a conjugate plane system
the first is the light source, aperature stop, objective. the second is field stop, specimen, eyepiece/eye
67
what is the formula for resolution
wavelength/2*NA (NA is numerical aperature)
68
what is numerical aperture
measure of light gathering ability of a lens
69
what is the refractive index of oil
1.5
70
what is the refractive index of air
1
71
what is numerical aperture of a dry lens
1
72
what is numerical aperture of oil lens
1+
73
what is the longest wave length
red
74
what is the shortest wavelength
violet
75
what is a stain
an organic compound containing benzene ring plus a chromophore and an auxochrome group
76
what is the function of chromophore
brings colour
77
whats the function of auxophore
binds the colour of chromophore to fibers or tissues
78
are acidic stains anionic or cationic
anionic
79
what are acidic stains used for
gram negative bacteria
80
what are basic stains used for
gram positive bacteria
81
whats an example of an acidic stain
picric acid, nigrosine, congo red
82
whats an example of a basic stain
crystal violet, methylene blue, safranin
83
what are the two basic staining techniques
simple or differential
84
why is it bad to have too much bacteria on a slide
diminishes the amount of light that is able to pass through
85
why is heat fixation required
helps anchor bacteria to slide, and kills bacteria
86
what is streptococcus
chain of cocci
87
what is staphlococcus
unorganized cluster of cocci
88
what is sarcinia
cube of cocci
89
how do you do a positive stain
put basic stain on slide for 30 seconds, rise excess dye off
90
how do you do a negative stain
no heat fixation needed, nigrosin at one end of slide, bacteria in nigrosin drop, spread dot to other end of slide with another slide at a 45 degree angle
91
how many chemical reagents are needed for differential staining
4 chemical reagents
92
what is the strength of differential staining
you can differentiate gram negative and gram positive bacteria on the same slide
93
how do you do a differential stain
start with heat fixed slide, apply basic stain (crystal violet), wash, grams iodine, wash, alcohol, wash, other basic stain, wash
94
what is the function of grams iodine
kills bacteria and increases cells affinity for a stain

Microbiology (6 decks)

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