Lab Practical Flashcards
(107 cards)
1
Q
What is purpose of the Bacterial contamination lab?
A
Methods to prevent contamination
2
Q
How do you calculate total magnification?
A
objective lens X ocular lens = total magnification
3
Q
Giardia trophozite?
A
Protozoa
4
Q
Amoeba?
A
Protozoa
5
Q
Plasmodium falciparum trophozites?
A
Protozoa
6
Q
Trypanosoma
A
Protozoa
7
Q
Candida Albicans
A
yeast (fungi)
8
Q
Rhizopus
A
mold (fungi)
9
Q
Aspergillus
A
mold (fungi)
10
Q
purpose of Aseptic transfers lab
A
minimize contamination to yourself, others, environment, source culture, and media
11
Q
Inoculating tools?
A
- Loop 2. Bunsen burner
12
Q
purpose of simple stains lab?
A
cells are stained with a colored dye to make them/structures more visible
13
Q
Morphology/Arrangement of:
- Staphylococcus epidermis
- Micrococcus luteus
- Bacillus megaterium
- Rhodospirillium
A
- cluster cocci
- cluster cocci
- string bacilli
- single spirulum
14
Q
Purpose of Gram stain lab
A
to distinguish and identify gram (=) or (-) bacteria
15
Q
List the steps of a gram stain
A
- A heat-fixed smear is covered w/crystal violet
- CV is washed off with distilled water & iodine applied
- decolorization with alcohol
- Alcohol rinsed and safranin applied
16
Q
Gram stain results
A
Gram (-)= reddish pink
Gram (+) = purple
17
Q
Gram positive or negative?
1. Staphylococcus epidermis
2 Escherichia coli
3.Bacillus megaterium
A
- (+)
- (-)
- (+)
18
Q
Purpose of acid fast stain
A
differential stain; to identify members of mycobacterium
19
Q
what is the stain used in acid fast stain
A
carbolfuchsin(+) counterstain is methylene blue or brilliant green
20
Q
Why is carbolfuchsin used in an acid fast stain?
A
waxy wall repels typical aqueous stains
21
Q
What are representative bacteria for acid fast staining?
A
mycobacteria
22
Q
What are representative bacteria for capsule staining?
A
Streptococcus pneumonia
23
Q
what is the purpose of capsule staining?
A
differential stain; allows detection of extracellular capsule
24
Q
what types of stains are used in capsule staining?
A
Congo red or nigrosin
25
What is the purpose of endospore staining?
differential stain; allows detection of presence and location of endospore
26
What types of stains are used in endospore staining?
malachite green to stain endospore; safranin for counterstain
27
Why is endospore staining different?
Endospore is made of keratin and resistant to staining
28
What are representative bacteria for endospore staining?
Bacillus and Clostridium
29
What is the purpose of the blood agar lab?
isolation and cultivation of fastidious bacteria and differentiate based on hemolytic characteristics
30
define selective media
enhances isolation procedure by inhibiting growth of some organisms, encouraging others
31
define differential media
an indicator to expose differences b/w organisms
32
streak plate method
used to isolate individual organisms from a mixed culture
33
alpha hemolysis
partial destruction of red blood cells w/ greenish discoloration
34
beta hemolysis
complete destruction of RBC; clearing on plate
35
gamma hemolysis
nonhemolysis; simple growth, no change in medium
36
purpose of mannitol salt agar lab
selects for bacteria that can tolerate high salt concentration
37
Staphylococcus aureus
yellow growth on mannitol salt agar plate
38
Maconkey agar purpose
to isolate and differentiate members of Enterbacteriacae based on ability to ferment lactose
39
poor growth on Mac plate
inhibited by CV and/or bile. Gram (+)
40
growth/reddish color Mac plate
produces acid from lactose fermentation. Gram (-) or coliform
41
Purpose of Eosin Methylene Blue lab
isolation of fecal coliforms
42
Eosin Methylene Blue lab: poor growth
inhibited by eosin methylene blue; gram (+)
43
Eosin Methylene Blue lab: good growth
not inhibited by eosin methylene blue; gram (-)
44
Eosin Methylene Blue lab: dark colored growth
lactose/sucrose fermentation
45
Eosin Methylene Blue lab: pink colored growth
little lactose fermentation
46
Purpose of catalase test lab
to identify organisms that produce the enzyme catalase
47
Anaerobic respiration
reduce inorganic molecules such as nitrate or sulfate
48
Aerobic respiration
reduce oxygen to water or other compounds
49
fermentation
production of nitrogen gas
50
what is the reagent used in catalase test?
hydrogen peroxide
51
purpose of oxidase test
to identify bacteria containing enzyme cytochrome c oxidase
52
Purpose of Nitrate reduction test
differentiates Enterbacteriacae from other Gram (-) rods that either do not reduce nitrate or nitrite or reduce it beyond
53
Nitrate Reduction positive reaction:
Red color after adding reagents A&B= nitrate reduction to nitrite
54
Nitrate Reduction reaction after adding zinc:
red color after zinc= no nitrate reduction
55
no color change after zinc:
nitrate reduction to nongaseous compound (+)
56
Purpose of Phenol Red Broth
to differentiate members of Enterbacteriacae from other gram neg rods
57
Phenol Red Broth: yellow color
acid production from fermentation of a carbohydrate lowers pH and turns broth yellow
58
Phenol Red Broth: Bubble in durham tube
gas produced
59
Phenol Red Broth: pink color
degradation of peptones/alkaline end products
60
Purpose of Methyl Red Voges-Proskauer test
to differentiate members of Enterbacteriacae from other gram neg rods
61
MR positive
red color= mixed acid fermentation
62
MR negative
no color change= no mixed acid fermentation
63
VP positive
red color=acetoin production
64
VP negative
no color change= no acetoin production
65
MR reagent
Methyl red dye & alcohol
66
VP reagents
A(alpha naphthol/alcohol) & B(potassium hydroxide and water)
67
Purpose of Citrate test
to determine ability to use citrate as sole source of carbon
68
Why is citrate used?
to provide a means for enzyme citrate permaze to transport, but does not support citric acid cycle
69
Positive citrate test
Blue color= citrate utilized (+)
70
growth; no color change
citrate utilized (+)
71
No growth or color change
citrate not utilized (-)
72
Purpose of starch hydrolysis lab
to isolate and identify Gagenerella vaginalis & differentiate members of Corynebacterium, Bacillus, Clostridium....etc...
73
Positive starch hydrolysis
clearing around growth; Amylase present
74
Negative starch hydrolysis
no clearing; Amaylase not present
75
reagent in starch hydrolysis test
iodine
76
why is iodine used in starch hydrolysis?
to detect presence or absence of starch
77
Purpose of Urea Hydrolysis lab
to differentiate based on ability to hydrolyze urea w/enzyme ureas
78
Positive Urea Hydrolysis
pink= rapid urea hydrolysis; strong urease production
79
Negative Urea Hydrolysis
orange/yellow= no urea hydrolysis; no urease production
80
Purpose od Gelatin Hydrolysis lab
to determineability to produce gelitanase
81
positive gelatin
gelatin is a liquid= gelatinase present
82
negative gelatin
gelatin is a solid= no gelatinase present
83
Purpose of SIM lab
sulfur reduction, indole production, motility
84
Reagent used in SIM
Kovac's reagent
85
Positive S. reaction
black in the medium; sulfur reduction
86
Negative S. reaction
no black; sulfur is not reduced
87
Positive I. reaction
Red in Kovac's reagent layer; tryptophan is broken down into indole and pyruvate
88
Negative I. reaction
no color change in Kovac reagent layer; tryptophan is NOT broken down into indole and pyruvate
89
Positive M.
growth radiating from stab line
90
Negative M.
No growth radiating from stab line
91
Purpose of gel eletrophoresis
analyze DNA fragments and determine size of molecules
92
how does gel electrophoresis work?
charged molecules enter cell walls. molecules with a (-) charge move towards (+) electrode and vice-versa
93
what happens to smaller sized molecules?
quicker and easier migration
94
what happens when there is a greater amount of charge
faster migration
95
Purpose of ELISA
antibody measurement & detection of antibodies
96
Steps of ELISA
1. Anitgen added to wells
2. wash away unabsorbed material
3. serum added & binds w/Ab present; wash
4. substrate added
97
what occurs when the substrate is added?
substrate is peroxidase; converts peroxide to H2O + O2; which oxidizes aminosalidase (brown reaction); easily observed
98
what is the purpose of the antimicrobial susceptibility lab?
to measure the effectiveness of antibiotics
99
Which antibiotic creates the largest zone of inhibition?
Eyrthrmycin
100
How does penicillin work?
it inhibits the cross-linking of peptidoglycan in Gram + cell walls
101
Purpose of UV radiation Damage and repair lab
to measure decontamination of UV& ability to penetrate various objects
102
prolonged exposure to UV
distort DNA molecules & interfere with DNA replication and transcription
103
light repair/photoreactivation
DNA photolayse; monomerizes dimer & reverses original reaction
104
excision repair/dark repair
of enzymes involved; make DNA double stranded again
105
Taenia
Tapeworm
106
Ascaris
roundworm
107
Trichinella spiralis
roundworm
