Lab Midterm Flashcards
1
Q
Examples of eukaryotic microbes
A
fungi, algae, and protozoa
2
Q
Mixture of nutrients in which a microorganism can grown
A
medium/media
3
Q
Comes from red algae.
Melts at 100 C
Solidifies at 40 C
A
agar
4
Q
medium that has known amounts of chemicals
A
defined medium
5
Q
medium that has chemically undefined components such as yeast extract or peptone
A
complex medium
6
Q
killing or removal of all living organisms from a medium
A
sterilization
7
Q
Sterilization technique for media and glass
A
Autoclave at 121 degrees C
8
Q
Sterilization technique for loops and glass
A
Dry heat: flaming, hot air
9
Q
Sterilization for heat sensitive liquids like antibiotics
A
filtration
10
Q
sterilization for surfaces
A
Radiation: UV, gamma rays
11
Q
Sterilization for heat sensitive materials such as ethylene oxide
A
cold sterilization
12
Q
occur naturally on or in body, don’t cause infection under normal circumstances
A
Resident (normal) microbiota/flora
13
Q
temporary on body, can’t grow on skin because too dry and acidic
A
Transient flora
14
Q
hospital acquired infection
A
Nosocomial infection
15
Q
number of microorganisms required to establish an infection
A
infectious dose
16
Q
a group of genetically identical bacteria, arising from a single cell on an agar plate
A
colony
17
Q
Three types of whole colony shape
A
round, irregular, rhizoid
18
Q
Three types of margin shape
A
smooth/entire, lobate, filamentous
19
Q
three types of elevation
A
convex, umbonate, flat
20
Q
Common normal flora
A
Staphylococcus, Acinetobacter, Propionibacterium
21
Q
Triclosan
A
liquid soaps
22
Q
Triclocarban
A
bar soaps
23
Q
antibacterial and anti fungal agents that disrupt the cell membrane synthesis
A
soaps
24
Q
What do soaps really do?
A
gets rid of transient flora
25
colony characteristics
colony morphology
26
unwanted organism which has been accidentally introduced into the culture
contaminant
27
some examples of aseptic technique
washing hands, disinfecting benches, sterilizing inoculating loops
28
a culture that contains only one kind of microorganism
pure culture
29
technique for diluting bacteria on agar plates; can be used to isolate bacteria from a mixture
streak plate
30
Common streak plate mistakes
not flaming between quadrants, not letting the loop cool, going back to the previous quadrant too much/not enough
31
Colony morphology: off-white, semi translucent, round, smooth, produces a dark colony with a green metallic sheen on EMB plate
Escherichia coli
32
Colony morphology: white, opaque, and small
Staphylococcus epidermis
33
makes cells more visible by adding contrast between cells and background
staining
34
1st step in staining cells, can be made from solid or liquid culture
smear
35
kills microorganisms and sticks them to slide to allow for easier visualization and staining
heat fixation
36
a result of staining, allows for visualization of cells
contrast
37
aqueous or alcohol solution of a single basic dye; highlights entire cells, stains every cell the same
Simple stain
38
shape of cell, visible only under magnification of microscope
morphology
39
arrangement of pairs of cocci
diplococcus
40
arrangement of cocci in random or grape like structures
staphylococcus
41
chain of cocci or bacilli
streptobacillus/streptococcus
42
tetrad or cubical packets of cocci
micrococcus
43
spiral with an axial rod
spirochetes
44
incomplete spiral
vibrio
45
irregular or variable shaped cell
pleomorphic
46
Colony morphology: yellow and opaque, gram positive
Micrococcus luteus
47
staphylococci, gram positive
staphylococcus epidermis
48
small, random bacilli, peritrichous, gram negative,
escherichia coli
49
spiral, gram negative
spirosoma linguale
50
large, street bacilli, endospores make them resistant to UV
bacillus megaterium
51
streptococci
streptococcus mutans
52
curved rods, monotrichous
Vibrio natriegens
53
filamentous rods
streptomyces coelicolor
54
diplococci or tetrads, can quickly repair DNA damage caused by UV
deinococcus radiodurans
55
total magnification =
magnification of the ocular lens (10x) multiplied by the objective lens
56
if an objective lens is in focus, when you change to another objective it should remain relatively in focus
parfocal
57
concentrates light going to the stage
condenser
58
controls amount of light accessing the stage
iris diaphragm
59
the distance between 2 points at which the points can be seen as two separate, distinct entities
resolving power
60
maximum resolution of our compound light microscope
0.2 micrometers
61
reduces the amount of light scattered between the specimen and the object thereby increasing the resolution
immersion oil
62
move back and forth by dyne motor proteins; made of microtubules
flagella and cilia
63
there parts of a prokaryotic flagellum
filament
hook
motor - driven by proton or sodium motive force
64
flagella are attached at one or both ends of the cell; movement more rapid, spinning around from place to place
polar
65
flagella are inserted at many locations around the surface; movement typically slow and in a straight line
Ex. Proteus, Salmonella, Escherichia
peritrichous
66
one polar flagella
| Ex. Vibrio, Pseudomonas
monotrichous
67
many flagella at one end
| Ex. Rhodospirillum photometricum
lophotrichous
68
one flagella at each end
| Ex. Spirillum
amphitrichous
69
What does motility test medium contain
0.4% agar, tetrazolium salt
70
bacteria will reduce the tetrazolium salt as they carry out metabolism; what does tetrazolium salt look like in these condition
red
71
peritrichous
proteus vulgaris
72
peritrichous
spirillum volutans
73
distinguishes cell types
differential stain
74
color of gram positive cells
blue/purple
75
color of gram negative cells
red
76
Steps in gram stain
1. Crystal Violet - primary stain
2. Iodine - mordant
3. Ethanol - decolorizer (gram negative cells lose purple coloring)
4. Safranin - counterstain
77
How does iodine work as a mordant?
chemically binds to the molecules of crystal violet
78
have a thick peptidoglycan layer; alcohol is unable to leach out the crystal violet-iodine complex
gram positive
79
alcohol penetrates lipopolysaccharide layer and the thin peptidoglycan layer does not prevent the alcohol from removing the crystal violet-iodine complex
gram negative
80
streptobacilli, gram positive
bacillus cereus
81
counts all cells using a hemocytometer
direct microscopic count
82
counts only living cells using either a spread plate or pour plate
standard plate count
83
can be correlated to viable cell count; spectrophotometer
turbidimetric assay
84
MPN coliform index of less than or equal to 2.2 coliform per 100 mL of water
potable water
85
what does the presence of coliforms indicate
fecal contamination
86
Aerobic or facultative aerobic; gram negative; do not form endospores; rod shaped; ferment lactose and produce gas
coliforms
87
non-pathogenic bacterium whose presence in water indicated fecal contamination
indicator organism
88
favors the growth of certain microbes and inhibits competitors
Selective medium
| Ex - Laurel Sulfate Lactose (LSL) broth selects for gram negatie bacteria
89
visible indication of a physiological characteristic
Differential Medium
90
3 Tests of MPN technique
Presumptive, Confirmed, Completed
91
```
Presumptive Test
Medium:
Selective Component:
Selects for:
Differential Component
```
```
LSL broth
Selective component: Lauryl Sulfate
Selects for: intestinal bacteria
Differential component: lactose
intestinal bacteria that ferment lactose and produce gas in the Durham tube
```
92
```
Confirmed Test
Medium:
Selective Component:
Selects for:
Differential Component:
```
Brilliant Green Lactose Bile (BLGB) broth
Selective components: brilliant green & bile
Selects for: coliform
Differential component: lactose
93
```
Completed Test
Medium:
Selective Component:
Selects for:
Differential Component:
```
Eosin methylene blue (EMB) agar
Selective Components: eosin and methylene blue dyes
Selects for: Gram negative bacteria
Differential component: lactose
94
produces fish-eye colony on EMB plate
Enterobacter aerogenes
95
water will leave the cell resulting in plasmolysis
hypertonic solution
96
water will enter the cell until the cell can no longer take in water
hypotonic solution
97
there will be no net flow of water through the cell
isotonic solution
98
prefers no salt but can tolerate higher salt concentrations
halotolerant
| Ex. Staphylococcus epidermis
99
grow best at high salt concentrations
halophile
| Ex. Vibrio natrigenes
100
requires 15-30% salt
extreme halophile
| Ex. Halo bacterium salinarium
101
pH at which the organism grows best
optimum pH
102
grow best at low pH
Acidophiles
103
grow best at pH close to 7 (most bacteria)
Neutrophiles
104
grow best at pH>7
Alkalinophiles
105
several pH units at which the organism can grow
pH range
106
used to sterilize surfaces; 10-400nm; causes thymine dimers
UV
107
most damaging wavelength to nucleic acids
260nm
108
adjacent thymines covalently bond to each other resulting in mutations or death of cell
thymine dimers
109
grow best at high temperatures
thermophiles
110
grow best at the temperatures comfortable for humans
mesophiles
111
grow best as low temperatures
physchrophiles
112
What kind of stain is a capsule stain
background is stained but the capsule is not
113
Functions of a capsule
```
prevent desiccation
reserve energy source
attachment to host cell
resists phagocytosis
may enhance ability to cause disease
```
114
Procedure for a capsule stain
Drop of Congo Red - stains background
Mix of organism then let dry
Flood with Manival's stain - stains cells
115
Why should you let the capsule stain air dry?
Heat fixing it would kill the cell and dry out the capsule which is mostly water
