Lab Exam Flashcards
1
Q
Positive result of Catalase test
A
bubbles
2
Q
substrates of Catalase test
A
Hydrogen peroxide & water
3
Q
Product of catalase test
A
Oxygen
4
Q
What is catalase?
A
Enzyme found in organisms that live in oxygen to protect them from oxidative byproducts
5
Q
Catalase test reaction
A
H2O2–> 2 H2O + O2
6
Q
Staphylococcus Aureus (gram reaction, shape, arrangement)
A
Gram positive, Cocci, Staphy (clusters)
7
Q
Escherichia Coli (gram reaction, shape, arrangement)
A
Gram Negative, Single Bacilli
8
Q
Countable plate size
A
30-300 colonies
9
Q
Individual tube dilution =
A
amt transferred/ transferred +dilutent
10
Q
Total Tube dilution =
A
product of ind tube dilutions
11
Q
Total plated dilution =
A
total tube dilution x plated amt
12
Q
cfu/ml count =
A
colony count x reciprocal of plated dilution
expressed in scientific notation
13
Q
mordent in gram stain process
A
Gram’s Iodine
14
Q
decolorizing agent in gram stain
A
ethanol
15
Q
Primary stain in gram stain
A
Crystal violet
16
Q
counterstain in Gram stain
A
safranin
17
Q
Gram stain process
A
- Crystal Violet (60 sec)
- Rinse with water
- Grams Iodine (60 sec)
- Rinse with water
- Ethanol (8-12 sec)
- Rinse with water
- Safranin (30 sec)
- Rinse with water
- Blot with bibulous paper
18
Q
After Gram stain Gram negative cells appear
A
pink
19
Q
After gram stain Gram positive cells appear
A
purple
20
Q
“Staphy-“ arrangement
A
clusters
21
Q
“Strepto-“ arrangement
A
chains
22
Q
diplo- arrangment
A
double
23
Q
tetrad
A
cocci arrangement - cluster of 4
24
Q
genus identified with Acid-fast staining
A
Mycobacterium
25
Wax-like, nearly impermeable cell walls of acid-fast organisms contain _____.
Mycolic acid
26
Because of their wall components, acid-fast organism are highly resistant to
disinfectants & dry conditions
27
Primary stain in acid-fast staining
carbolfuchsin - lipid soluble & contains phenol which help stain penetrate the cell wall
28
exoenzymes that lyse red blood cells and degrade hemoglobin
hemolysins
Bacteria can produce different types of hemolysins
29
Three categories of hemolysins
alpha hemolysis, beta hemolysis, & gamma hemolysis
30
beta-hemolysis
complete breakdown of the red blood cells and hemoglobin
| Displays on blood agar as clear zones surrounding individual colonies
31
alpha-hemolysis
partially breaks down read blood cells
| Displays as army green color on blood agar
32
gamma-hemolysis
no breakdown of blood cells
| Just looks like normal growth patterns with no clearing of blood
33
Nutrient Agar ( aka _______) ingredients
Tryptic Soy Agar (TSA)
| Protein source, water, agar
34
Selective for gram negative organisms
```
Eosin Methylene Blue (EMB) &
MacConkeys Agar (suppresses gram pos)
```
35
Selective for gram pos organisms
Phenyl Alcohol Agar (PEA)
36
Differential for lactose/ sucrose fermenters & non-fermenters
Eosin Methylene Blue
37
Differential for lactose fermenters
MacConkeys Agar
38
fermenters turn dark deep purple or metallic green
Eosin Methylene Blue
39
fermenters turn pink/purple
MacConkeys Agar (lactose fermenters)
40
Differential for mannitol fermenters
Mannitol Salt Agar
41
Fermenters turn yellow
Mannitol Salt Agar (mannitol fermenters)
42
Selective for high salt tolerant organisms
Mannitol Salt Agar
43
Escherichia Coli will grow on
Tryptic Soy Agar, Eosin Methylene Blue, MacConkeys Agar
44
Staphylococcus Aureus will grow on
Tryptic soy agar, Phenyl ethyl Alcohol (PEA), Mannitol Salt Agar
45
Types of selective media
EMB - selective for Gram neg
MAC - selective for gram neg
PEA - selective for gram pos
MSA - selective for high salt tolerant organisms
46
Differential Media
EMB - lactose and/or sucrose fermenters - green or dark pink
MAC - lactose fermenters - pink
MSA - mannitol fermenters
47
DNAse breaks down _____ to produce ______
DNA; nucleotides and nucleic acid chains
48
DNAse test reagent
Methyl Green Dye
49
Positive DNAase result
clear zone around organism
50
Urease test reagent
Phenol Red
51
Urease breaks down _____ and requires _____
Urea; water
52
by product of Urea breakdown
Ammonia
53
Positive Urease test
Bright pink broth
54
Negative Urease test
Salmon colored broth
55
4 IMViC tests
Indole, Methy Red, Voges-Proskauer, Citrate
56
Indole testing for what enzyme activity
Tryptophanase
57
Tryptophanase breaks down _____ into ______, ______, & _________.
Tryptophan --> Pyruvate + Ammonia (NH3) + Indole
58
Indole test reagent
Kovac's reagent
59
Positive Indole test
purpley red on top
60
Negative Indole test
yellow on top
61
Methyl Red test is a _____
pH indicator
62
Methyl Red testing for production of
various acids (ie. lactate, formate, acetate
63
Positive Methyl Red test
Red = positive for acid production
64
Negative Methyl Red Test
Yellow = negative for acid production
65
Voges Proskauer detects production of _______.
acetoin
66
Reagents of Voges Proskauer test
Alpha-napthol & potassium hydroxide
67
Acetoin is a precursur to
2,3 butanediol
68
Positive Voges Proskauer test result
Red cloud throughout
69
Negative Voges Proskauer test result
no red cloud/ neutral
70
Citrate Agar Slant reagent
bromothymol blue
71
What is citrate slate test testing for?
Enzyme citrate permease; can organism use citrate as it's sole carbon source
72
Positive citrate test
Blue - alkaline = kreb's cycle is happening
73
Negative citrate test
Green - acidic
74
Malonate Test reagent
Bromothymol blue
75
Malonate test is testing for
can organism use Malonate as it's sole carbon source
76
positive malonate test
blue
77
negative malonate test
green
78
Oxidase test positive result
purple swab or paper
79
Oxidase test tests for enzyme
cytochrome oxidase
80
Carbohydrate tests/ Fermentation tubes positive for fermentation if
tube turns yellow
81
Fermentation tube reagent
Phenol Red
