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Lab Quiz 3 Flashcards

1
Q

What 3 things contribute to the ubiquity of microorganisms?

A

small size
rapid reproduction
metabolic diversity

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2
Q

What fungus can produce aflatoxins?

A

Aspergillus flavus

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3
Q

What was the suspending medium used for spices?

A

0.85% NaCL

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4
Q

What type of agar was used for spices?

A

TSA

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5
Q

Procedure for spices

A

suspend about 100 mg of spice in a tube of 10 mL suspending medium and mix
Perform a serial dilution (10-1, -2, -3)
Transfer 1 ml from each dilution to sterile Petri dishes
Add 20mL molten TSA
Incubate at 30C
Examine for 2 lab periods

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6
Q

Procedure for other location

A 
Swab a location with sterile swab
Inoculate a third of a TSA plate
Use sterile loop to streak for isolation
Incubate at temperature corresponding to location
Examine for 2 lab periods
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7
Q

What’s an example of a social bacteria?

A

myxobacteria

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8
Q

How do myxobacteria kill prey?

A

releasing lytic enzymes and antimicrobial compounds

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9
Q

What happens to Myxobacteria xanthus upon starvation?

A

vegetative cells aggregate into multicellular fruiting bodies
a subpopulation of fruiting bodies differentiates into dormant, stress resistant myxospores

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10
Q

What species is morphologically between bacteria and fungi?

A

Actinomycetes

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11
Q

What are the features of Actinomycete colonies

A

extensive, branched mycelium that may give rise to conidiospores
small, compact, soft to leathery

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12
Q

What do the hyphae of Actinomycete develop into?

A

very fine “vegetative” or “submerged” mycelium

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13
Q

What does the feeding mycelium of Actinomycete become (sometimes)?

A

aerial mycelium that is thicker and may give a powdery appearance to the colony

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14
Q

What causes a colony to look powdery?

A

production of conidiospores

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15
Q

What genus is a major source of antibiotics?

A

Streptomyces

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16
Q

Photosynthetic microbes

A

Cyanobacteria, Green and Purple bacteria

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17
Q

Cyanobacteria perform

A

oxygenic photosynthesis

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18
Q

Green and purple bacteria perform __

A

anoxygenic photosynthesis

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19
Q

Green and purple bacteria can’t perform oxygenic photosynthesis because __

A

they are unable to utilize water as an electron source

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20
Q

what pigment do cyanobacteria use to collect sun energy

A

chlorophylls

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21
Q

what pigment do green and purple bacteria used to collect sun energy

A

bacteriochlorophylls

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22
Q

What are two accessory pigments used by photosynthetic bacteria?

A

carotenoids

phycobiliproteins

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23
Q

green and purple sulfur bacteria are ____ (relationship to oxygen)

A

obligate anaerobes

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24
Q

purple nonsulfur bacteria are ___ (relationship to oxygen)

A

facultative anaerobes

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25
What is the purpose of Winogradsky's column?
to illustrate how bacteria develop in certain habitats in response to appropriate environmental conditions
26
Sequence of equations - Wino column
organic matter + O2 -> organic acids + CO2 organic acids + SO4 -> H2S + CO2 H2S + CO2 -(light)-> carbohydrate + S
27
What occurs in the first phase of the Wino column?
hetertrophic microbes oxidize organic matter and consume O2, making it anaerobic
28
What occurs in the second phase of the Wino column?
anaerobic sulfate-reducing bacteria reduce sulfates and sulfites to hydrogen sulfide (organic acids act as electron donors)
29
What occurs in the third phase of the Wino column?
H2S is used as an electron donator to reduce CO2 into carbohydrates by photosynthetic organisms such as purple and green sulfur bacteria (light is required)
30
What occurs in the fourth phase of the Wino column?
H2S is used as an electron donator to reduce CO2 into carbohydrates by photosynthetic bacteria such as purple non-sulfur bacteria (light is required)
31
What's present in the aqueous layer of the Wino column at the end of the experiment?
``` AEROBIC protozoans fungi algae aerobic bacteria ```
32
What's present in the mud layer of the Wino column at the end of the experiment?
ANAEROBIC | photosynthetic bacteria
33
Purple and green sulfur bacteria present in the Wino column
Chromatin | Chlorobium
34
Purple non-sulfur bacteria present in the Wino column
Rhodospirillum Rhodopseudomonas Rhodomicrobium
35
Are purple non-sulfur bacteria present in the upper portion of the Wino column? How can you tell? How are they able to function?
Yes, there will be a rust colored zone, they use organic matter as an electron donor
36
What type of bacteria is present throughout the Wino column?
Heterotrophic
37
What are the two possible forms of selection for choosing specific growth conditions?
repressive selection | enrichment selection
38
What is repressive selection?
repressing the growth of interfering microbes while permitting the growth of the culture sought
39
What is enrichment selection?
encouraging the growth of the sought after microbe so it will out compete its competitors
40
Why doesn't reducing the sample size help to avoid contamination?
The organism sought after is usually a minor part of the population
41
What is differential plating?
isolation from a mixed culture by making it easier to recognize the culture sought without introducing any inhibitory or enrichment substance
42
What are possible selective influences in media?
temperature of incubation pH oxygen
43
Habitat of Escherichia coli
lower intestinal tract
44
Do E. coli have endospores?
no
45
What components of MacConkey makes it selective for gram-negative bacteria?
crystal violet and bile salts
46
What components of MacConkey allows it to differentiate between fermenters of lactose and nonfermenters of lactose?
neutral red indicator
47
Habitat of Enterococcus faecalis
lower intestinal tract
48
Do E. faecalis have endospores?
no
49
What components of Colistin-Nalidixic Acid agar makes it selective against gram-negative bacteria
two antibiotics
50
What kind of hemolysis is E. faecalis capable of?
gamma
51
What kind of hemolysis is Staphylococcus capable of?
gamma or beta
52
Do Staphylococcus have endospores?
no
53
What do yellow colored colonies on Mannitol Salts plate indicate?
ability to ferment mannitol
54
Habitat of Bacillus
soil
55
Habitat of Pseudomonas
soil
56
Do Bacillus have endospores?
yes
57
Do Pseudomonas have endospores?
no
58
What does Pseudomonas enrichment have that makes it selective?
p-hydroxybenzoate
59
What's the difference between Pseudomonas agar F and agar P plates?
F produces yellow-green pigment that can be detected under UV light P produces blue-green pigment that can not be detected under UV light
60
What form of nitrogen can Azotobacter reduce?
atmospheric nitrogen (N2) to ammonia
61
When do Azotobacter produce capsules and what do they do?
when growing as N2 as nitrogen source; to protect nitrogenase
62
When do Azotobacter produce cysts and what do they do?
when media becomes deficient in carbohydrates and other nutrients; germinate to vegetative cells when conditions become favorable
63
What makes Ashby's plate selective for nitrogen-fixing bacteria?
absence of nitrogen, so the only source is atmospheric nitrogen
64
Are E. coli motile?
yes
65
Are Azotobacter motile?
variable
66
Are Staphylococcus motile?
non
67
Are Enterococcus motile?
no
68
Are Pseudomonas motile?
yes
69
Are Bacillus motile?
yes
70
How is the DNase test agar used?
distinguish Serratia from Escheerichia and Enterbacter | Serratia produces an extracellular deoxyribonuclease that can be detected as a violet colored zone
71
How is the catalase test used?
differentiate Staphylococcus (catalase +) from Streptococcus (catalase -)
72
How is the oxidase test used?
detects cytochrome oxidase enzyme | E. coli, Enterobacter, and Serratia are oxidase +
73
How is the indole test used?
differentiates E. coli (indole +) and Enterobacter (indole -)
74
What does alpha hemolysis look like on BAP?
greenish discoloration around colony
75
What does beta hemolysis look like on BAP?
transparent area around colony
76
What is alpha hemolysis?
partial activity
77
What is beta hemolysis?
complete activity
78
What is gamma hemolysis?
no activity
79
What does gamma hemolysis look like on BAP?
no change in agar
80
Which species was tested on a Mannitol salt plate?
Staphylococcus
81
Which species was initially isolated on BAP?
Staphylococcus
82
Which species was isolated on MAC plate?
E. coli
83
Which species was isolated on CNA plate?
E. faecalis
84
Which species was tested on DNase plate?
E. coli
85
Which species was tested with an indole test?
E. coli
86
What was the TTC deep test performed for?
to detect motility (presence of flagella)
87
Which species was tested with TTC deep?
E. coli E. faecalis Bacillus Staphylococcus

Micro (15 decks)

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