Lab Quiz #1 Flashcards
1
Q
Binomial system: what is it used to name, who proposed it
A
Used to name microorganisms
Devised by Carl Linnaeus
2
Q
What are the components of the binomial system? Which name is capitalized and which is italicized?
A
Genus and species name
Genus name is capitalized
Both names are italicized
3
Q
Pure culture
A
Culture in which each cell is a direct descendant of a single cell from a culture containing cells of only one species
4
Q
Aseptic technique
A
Procedures used to prevent unwanted microorganisms from causing contamination of a specimen
5
Q
Culture medium
A
Solid or liquid preparation used to grow, transport, and store microorganisms
6
Q
Two methods of obtaining pure cultures
A
Streak plate method
Drop dilution method
7
Q
Colony
A
Visible mass or population of cells originating from a single cell
8
Q
Agar
A
Complex polysaccharide, usually extracted from red algae, that is used as a solidifying agent in the preparation of culture media
9
Q
Micrococcus luteus: color, type of microorganism
A
Creamy-yellow colored bacteria
10
Q
Serratia marcescens: color, type of microorganism
A
Red colored bacteria
11
Q
Prodigiosin
A
Pigment that makes Serratia marcescens red
12
Q
Tryptic soy agar
A
General purpose growth medium
13
Q
Clonal
A
Term to describe clones within a colony
14
Q
Colony morphology: punctiform
A
Colony that looks like tiny dots
15
Q
Colony morphology: circular
A
Colony that looks spherical
16
Q
Colony morphology: filamentous
A
Colony that looks hair-like
17
Q
Colony morphology: irregular
A
Colony that doesn’t look like a regular set shape
18
Q
Colony morphology: rhizoid
A
Colony that looks root-like
19
Q
Colony morphology: spindle (lens)
A
Colony that looks leaf-like or ellipsoidal
20
Q
Colony elevation: flat
A
Colony that does not rise much from plate/ looks plateau-like
21
Q
Colony elevation: raised
A
Colony that comes off of plate in a dome-like manner, evenly
22
Q
Colony elevation: convex
A
Colony that comes off of plate in an upside-down bowl shape
23
Q
Colony elevation: pulvinate
A
Colony that comes off of plate in a sharp dome shape
24
Q
Colony elevation: umbonate
A
Colony that comes off of plate with a raised center, but fairly flat surroundings
25
Colony edge or margin: entire (even)
Colony that has an even, circular edge
26
Colony edge or margin: undulate (wavy)
Colony that has a crumpled, wavy edge
27
Colony edge or margin: filamentous
Colony that has a hair-like edge
28
Colony edge or margin: lobate (lobes)
Colony that an edge that looks like the Nickelodeon logo
29
Colony edge or margin: errose (serrated)
Colony that has a sun-like edge ("lobes" are smaller and sharper than lobate's)
30
Colony edge or margin: curled
Colony that has an edge that looks like tree rings
31
Colony appearance: 5 options
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Smooth
Glistening
Rough (dry)
Wrinkled
Powdery (spores)
```
32
Drop-dilution method
Pure colony attainment
| Bacteria are pipetted directly into a tube of molten agar, then diluted into two other tubes
33
P20 micropipettor: volume range
0.5-20 microliters
34
P200 micropipettor: volume range
20-200 microliters
35
P1000 micropipettor: volume range
200-1000 microliters
36
Compound or bright-field microscope: what is it and how does it work
Commonly used microscope
Forms dark image against a brighter background
Two magnifying lenses (one in ocular and one in objective) work together to magnify an object
37
Microscope
Instrument that produces enlarged images of small objects
38
Disadvantages to compound/bright-field microscope
Limited resolving power
| Organelles unidentifiable without staining
39
Objective lens: what are they, and what magnifications do they have
Lenses that are mounted on revolving nosepiece
| 3 magnifications: low power (10x), high power (40x or 43x), and oil immersion (100x)
40
Ocular lens/eyepiece
Part of microscope that user looks through
| Magnifies the real image formed by objective lens
41
Stage
Where slide is placed
42
Coarse adjustment knob
Used to bring object into approximate focus
43
Fine adjustment knob
Used to precisely focus on object
44
Condenser
Located beneath stage
| Focuses cone of light from light source onto slide
45
Diaphragm lever
Located below condenser
| Used to open and close iris diaphragm, making slide lighter or darker
46
At higher magnification, is more or less light needed than at lower magnification?
More light is needed
47
How does magnification work?
Makes things look bigger
48
Resolving power (D)
Degree of definition of the fine structure of the material being observed
Enables perception of two closely adjacent points as separate
49
Do smaller or larger wavelengths of light permit greater resolving power?
Smaller
50
Numerical aperture
Measure of light-gathering ability
51
Refractive index (n)
Amount that light rays are bent as they pass through different media
52
Why immersion oil is used at high magnification
Refractive index of air is lower than glass: as light rays pass from glass slide into air, they are bent, causing them to miss the objective lens and thus causing a decrease in light
Loss of refractive light is compensated for by immersion oil (same refractive index as glass), increasing amount of light that enters objective lens
53
Yeast species studied in lab
Saccharomyces cerevisiae
54
Bacteria species commonly used in lab
Escherichia coli
55
Name for rod shaped bacteria
Bacillus
56
Name for spherically shaped bacteria
Coccus
57
Name for rigid, helical bacteria
Spirillum
58
Name for flexible, helical bacteria
Spirochete
59
Name for bacteria with one curve (crescent moon shaped)
Vibrio
60
Name for pair of spherical bacteria
Diplococcus
61
Name for chain of spherical bacteria
Streptococcus
62
Name for cluster of spherical bacteria
Staphylococcus
63
Name for group of 4 spherical bacteria
Tetrad
64
Name for group of 8 spherical bacteria
Sarcina
65
Sporangium
Cell containing spore
66
Rod shaped sporangium
Bacillus shaped; same appearance as other vegetative cells
67
Spindle shaped sporangium
Ellipsoidal shape due to central swelling
68
Drumstick shaped sporangium
One end enlarged
69
3 shapes of endospores
Spherical
Ellipsoidal
Cylindrical (rod-shaped)
70
3 locations of endospores
Central (spore located in middle of cell)
Terminal (spore located at end of cell)
Subterminal (spore located between middle and end of cell)
71
Flagella
Long whip-like organelles responsible for motility
72
Motility
Ability to move spontaneously and actively
73
3 parts of flagellum
Basal body (rod with series of rings, located closest to bacterial cell), hook (attaches basal body to filament), filament (extends out of bacterial cell, attached to hook)
74
Chemotaxis
Movement of cells towards attractants or away from repellants
75
Flagella distributed all over surface of cell
Peritrichous
76
Flagella clustered at one or both ends
Lophotrichous
77
One flagellum at the end of the cell
Polar monotrichous
78
Two flagella, one at each end of cell
Polar amphitrichous
79
Brownian motion: what causes it?
Bacterial cells in an aqueous environment are constantly hit by random motion of water molecules, causing them to move
80
Rhodospirillum rubrum and staphylococcus epidermidis: which one displays true flagellar motion?
Rhodospirillum rubrum
81
Darkfield microscopy: how does it work?
Darkfield condenser (contains opaque disk): blocks light that would enter objective directly
Only light that has been reflected or refracted by specimen enters objective directly
Specimen is light on a dark background
82
Phase-contrast microscopy: how does it work?
Phase plate retards wavelengths so that they are 1/2 out of phase
2 rays of light brought together: troughs of one wave interfere with crests of another, generating contrast
Background is light, specimen is dark
83
Why bacteria can't be seen with great detail under regular microscopy
Refractive index of bacteria is nearly the same as that of the water in which they are suspended
84
2 things necessary for observation of structural and morphological detail of microbes
Greater magnification and better resolution
| Contrast between cells and background
85
2 chemical groups contained by dye
Chromophore
| Auxochrome
86
Chromophore
Provides color to dye
87
Examples of chromophore chemical groups
Azo (-NN), nitrose (-NO), nitro (-NO2), thio (-CS)
88
Auxochrome
Increase solubility of dye
89
Examples of auxochrome chemical groups
Amino (-NH2), hydroxyl (-OH)
90
Acidic dye: what its salt dissociates into
Negatively charged anion and metal cation
91
Acidic dye: what it is used for
Binds to positively charged microbial cell structures (basic structures) such as cytoplasm
92
Basic dye: what its salt dissociates into
Positively charged cation and anion
93
Basic dye: what it is used for
Binds to negatively charged molecules (acidic structures) like nucleic acids, many proteins, ribosomes, metachromatic granules, acidic waxes of acid-fast bacteria
94
Chromogen: is it a true dye?
Not a true dye because it is insoluble in water
95
Simple stain
One dye that stains a component of the microbial cell
96
Methylene blue: what does it stain? Does it stain acidic or basic cellular components?
Metachromatic granules
| Stains acidic cellular components
97
Species stained with methylene blue in lab
Saccharomyces cerevisiae
98
Differential stains
2 or more dyes, used to categorize cells into groups (e.g. Gram staining)
99
4 reagents used in Gram staining
```
Crystal violet (basic dye)
Iodine solution (mordant)
Ethyl alcohol (decolorizer)
Safranin (basic counterstain)
```
100
Mordant
Chemical that fixes dye by combining with it to form an insoluble compound
101
Gram-variable cells
Stain both purple (Gram positive) and pink (Gram negative) due to old age of culture
102
2 Gram positive bacteria used in lab
Staphylococcus epidermidis
| Bacillus subtilis
103
Gram negative bacteria used in lab
Escherichia coli
104
Capsules: what composes them, what are they used for, correlation exists between them and what type of bactiera
Made of polysaccharides
Used for cell adhesion
Correlation between presence of capsule and pathogenicity
105
Negative stain: used for viewing what, what does it do, what reagents are used for negative staining
Used for viewing capsule
Stains background rather than microorganism ("halo" around bacteria)
India ink or 1% nigrosin
106
Species of bacteria used in capsule stain
Klebsiella
107
Endospores
Dormant structures created during sporulation
108
Endospores are resistant to what 4 things?
Heat, radiation, harsh chemicals, dessication
109
When does endospore formation begin?
When cell growth ceases due to lack of nutrients
110
How spore staining works
Spores usually resist penetration of dyes, but will retain basic dyes when heated
Dye is removed from vegetative cells, but not spores
111
Stain used for spores
Malachite green
112
Counterstain used in spore staining for vegetative cells
Safranin
113
Species of bacteria that produces spores
Bacillus subtilis
114
How flagella staining works
Mordant is used to increase flagella diameter
115
Mordant and dye used in flagella staining
Mordant: tannic acid
Dye: fuchsin (basic dye)
116
Leifson's technique
Flagella staining method
| Mordant and dye are mixed and added at same time
117
Type of bacteria used in acid-fast staining
```
Mycobacterium phlei (acid-fast)
Staphylococcus (non-acid fast)
```
118
Why Mycobacterium are used for acid-fast staining
Cell walls have high lipid content and contain mycolic acids that are impervious to Gram staining
119
Reagents used for acid-fast staining and how they work
```
Carbol fuchsin (mordant, acid-fast organisms won't lose this dye when decolorized with acidified alcohol)
Loeffler's methylene blue (counterstain, non-acid fast organisms retain this dye)
```
120
Acid-fast staining is used in diagnosis of what disease?
Tuberculosis
121
Granules
Reserve materials accumulated in bacterial cells
122
Metachromatic granules: what type of reserve materials?
Phosphates
123
What genus of bacteria have metachromatic granules?
Corynebacterium
124
Causative agent of diptheria
Corynebacterium diphteriae
125
If Loeffler's methylene blue is used to stain granules, how does the cell appear?
Polychrome effect: granules appear purple while cells appear blue
Caused by alkalinity of dye
126
Type of bacteria used for granule staining in lab
Corynebacterium xerosis
127
Lysozyme
Enzyme used to remove cell wall of bacteria: attacks peptidoglycan by hydrolyzing glycosidic bond that connects N-acetylglucosamine with N-acetylmuramic acid
128
2 classes of fungi
Yeasts
| Molds
129
Molds
Multicellular, filamentous fungi that form elaborate branching networks of cells
130
Yeasts
Unicellular fungi that can reproduce sexually through formation of spores or asexually by budding
131
Hyphae
Filaments that extend from fungal spores or cell fragments
132
Mycelium
Network of hyphae
133
Chitin
Polysaccharide that comprises hyphal cell walls
134
Septate
Individual hyphae with regular cross-walls
135
Aseptate (nonseptate) hyphae
No cross-walls, often have multiple nuclei dispersed throughout the hyphal structure
136
Sporangiospores
Develop in saclike structures (sporangium) located at the tips of hyphae
Produce spores
137
Conidiospores
Not enclosed within a sac
Located at either tips or sides of hyphae
Produce spores
138
Chytridiomycota: simple or complex, unique structure, types of reproduction
Simplest of fungi
Form motile zoospores with flagella
Sexual and asexual reproduction
139
Zygomycota: where found, septate or aseptate, types of reproduction, example
Common in soil and decaying plant material
Aseptate
Sexual and asexual reproduction
Bread mold Rhizopus
140
Ascomycota: unique structure, function, types of reproduction, examples
Sac-like reproductive structures (ascus)
Major decomposers
Sexual and asexual reproduction
Aspergillus, Saccharomyces cerevisiae
141
Basidiomycota: another name, unique structure, types of reproduction, examples
Club fungi
Spore-producing structure called basidium
Sexual and asexual reproduction
Cryptococcus neoformans (human pathogen), mushrooms and toadstools
142
Vegetative vs aerial hyphae
Vegetative hyphae are used to obtain nutrients, anchored to medium
Aerial hyphae project upward and frequently produce spores
143
Rhizopus and Aspergillus: which produces sporangium and which produces conidia
Rhizopus produces sporangium
| Apergillus produces conidia
144
Stolon
Another name for aerial hyphae that connect rhizoids (vegetative hyphae of Rhizopus)
145
Aflatoxin
Carcinogenic compound produced by Aspergillus flavus (grows in spices)
146
Salmonellosis
Causative agent of salmonella (intestinal infection, also bacteremia- blood infection)
