Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

MCB 2610 > Lab Practical > Flashcards

Lab Practical Flashcards

(97 cards)

Start Studying
1
Q

What type of medium is SF broth/ BPB?

A

Selective

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is SF Broth/BPBused for?

A

detection and differentiation of enterococci from other cocci

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Positive SF broth/BPB and what it means

A

Yellow
glucose fermentation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Negative SF Broth/BPB and what it means

A

purple
does not ferment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What does BPB contain that inhibits aerobic respiration?

A

sodium azide
Inhibits electron transfer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What type of medium is MacConkey agar?

A

selective and differential

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What does MacConkey select for?

A

Gram-negative: selects against Gram-positive organisms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What does growth mean on MacConkey agar?

A

organism is Gram-negative

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How is MacConkey agar differential?

A

differential for lactose fermentation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What does pink MacConkeyy mean?

A

positive for lactose fermentation
acidic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What does orange MacConkey mean?

A

negative for lactose fermentation
neutral

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Purpose of Na+ Glucose plates?

A

serves as a control
any organisms will grow on it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What kind of medium is tryptic soy broth?

A

complex liquid media

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Positive TSB tube

A

turbidity/cloudy
this means there is growth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

negative TSB tube

A

clear

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What does amylase do?

A

enzyme that catalyzes starch hydrolysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How to test for amylase

A

Starch plate flooded with Gram’s iodine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Amylase positive

A

reddish/amber zone surrounding the colonies
- due to a lack of starch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Amylase negative

A

Dark color surrounding growth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What does Caseinase do?

A

enzyme that hydrolyzes milk proteins (Casein)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

How to test for caseinase?

A

casein plate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Caseinase positive

A

clear zone surrounding growth
- due to hydrolysis of casein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Casein negative

A

no clear zone surrounding growth
because there is no hydrolysis of casein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What does gelatinase do?

A

enzyme that hydrolyzes gelatin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
How to test for gelatinase?
cooling of gelatin tubes
26
Gelatinase positive
gelatin tubes remain liquid - because gelatin was hydrolyzed
27
Gelatinase negative
gelatine tubes remain solid
28
What does catalase do?
Protects cell from hydrogen peroxide by producing water and oxygen
29
How to test for catalase?
put colony sample onto filter paper squares and add 3% hydrogen peroxide
30
Catalase positive
sample bubbles immediately after adding a drop of hydrogen peroxide
31
Catalase negative
sample does not bubble after adding hydrogen peroxide
32
what does oxidase do?
oxidase activity indicates presence of cytochrome c (component of ETC)
33
How to test for oxidase?
Put colony sample onto parafilm and add drop of oxidase reagent
34
oxidase positive
turns blue
35
Oxidase negative
remains clear
36
What is fermentation
process involving the anaerobic oxidation of carbon substrates (sugars)
37
How to test for fermentation
durham tubes
38
Positive for fermentation
Gas detection or acid production
39
Gas detection
gas bubble present
40
acid production
penol red turns yellow in presence of acid remains red in neutral conditions
41
T/F fermentation always involves gas production
FALSE it always involves acid production but sometimes gas
42
How to test for motility
motility agar that contains triphenyltetrazolium chloride (TTC) whicha acts as a dye OR Hanging Drop slide
43
what does growth near the stab line of motility agar mean
no motility
44
what does growth that moves towards the top of motility agar mean?
motile and obligate aerobe
45
What does growth all over the tube mean in motility agar?
motile and can grow in low oxygen environments
46
How does hanging drop slide work
use with solid sample and put loop of bacteria onto slide Observe movement in a microscope
47
What is Gram stain used for
differentiate between gram nergative and gram positive bacteria
48
Gram positive
purple has lots of peptidoglycan
49
Gram negative
pink has very little peptidoglycan
50
Gram stain steps
C- crystal violet (1 min) R- rinse with water I- iodine mordant (1 min) then rinse E- ethanol (10 sec) then rinse S- safranin counterstain (35sec)
51
What does endospore stain do?
identifies endospore-forming bacteria
52
Endospore positive
green
53
endospore negative
pink vegatative cells
54
Coliforms
Gram-negative lactose fermenters resistant to detergents such as bile
55
Where are coliforms found
In GI tract of animals
56
What type of media is Lauryl-tryptose (LT) broth?
selective and differential
57
What is LT broth tubes used for?
testing for the presence of coliform
58
How are LT broth tubes selective and differential
select for intestinal bacteria Gas bubble forms for lactose fermenters
59
What does gas bubble mean in LT tubes
possible indicator for coliform must confirm
60
What is the quanilification for countable colonies
30-300
61
How to calculate CFU
(number of colonies)/(dilution factor)(volume plated)
62
What type of media is EMB plates?
selective and differential
63
How to confirm coliforms?
EMB plate
64
How are EMB plates selective and differential?
selective: selects for gram negative - contains dye that inhibits gram-positive differential: lactose fermentation
65
EMB positive
lactose fermentation present purple or metalic green sheen coliforms present
66
EMB negative
no lactose fermentation pink/clear growth
67
What is the purpose of blood agar?
differentiates between staphylococcus, streptococcus and enterococcus
68
alpha hemolysis
partial lysis cloudy green zone associated with streptococcus
69
beta hemolysis
complete hemolysis clear zone associated with streptococcus pyogenes and staphylococcus
70
gamma hemolysis
no hemolysis no change to blood agar associated with enterococcus
71
Why coagulase test?
Pathogenic strains of S. aureus contain the enzyme coagulase
72
Coagulase posititve
clumping after adding rabbit plasma indicates pathogenic S. aureus
73
Coagulase negative
no clumping after adding rabbit plasms
74
What does Sodium Thioglycollate broth tubes do?
reduces O2 to produce H20 maintains anaerobic environment in media
75
Growth only at top of sodium thioglycollate tubes
obligate aerobe
76
growth all the way through tube but concentrated at top of sodium thioglycollate tube
facultative anaerobe
77
Growth all the way through tube but slightly inhibited sodium thioglycollate tubes
fermenter
78
Growth as a thin band below the surface of sodium thioglycollate
microaerophile
79
growth only at the bottom of sodium thioglycollate tubes
obligate anaerobe
80
How does anerobic pouch method work?
methyl blue indicator is blue in anoxic environment turns clear in the presence of oxygen
81
What does growth in the anaerobic pouch mean?
facultative or obligate anaerobe
82
What does no growht in anaerobic pouch mean?
obligate aerobe
83
Nitrate reduction steps
must make culture anaerobically after incubation add nitrate A and B Add zinc to tubes that have no color change
84
Positive for nitrate reduction to nitrite
color changes to red after addition of nitrate A and B
85
What happens if there is no color change after addition of nitrate A and B
possibly no nitrate reduction BUT further testing needed
86
negative for nitrate reduction
zinc changes color to red - zinc converted nitrate present to nitrate
87
positive for full denitrification to N2
no color change after addition of zinc
88
bacteriostatic
prevents bacteria from reproducing
89
bacteriacidal
kills bacteria
90
antibiotic
metabolic product produced by some bacteria that prevents growth of another microrganism
91
Antibiotic discs assay- what to look for
zone of clearing around each disk formed by antibiotics
92
plaque
a clear area surrounded by otherwise confluent growth of the host result of phage induced cell lysis
93
What is the plaque assay used for
quantify infection phase particles within culture expressed as Plaque Forming units
94
PFU
number of plaques/ (dilution factor)(volume)
95
What does green citrate tubes mean?
negative no growth
96
What does blue citrate tubes mean
positive-growth alkaline
97
What does yellow citrate tubes mean?
positive-growth acidic

MCB 2610 (24 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions