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Microbiology Lab > Exam I > Flashcards

Exam I Flashcards

(183 cards)

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1
Q

Antiseptics

A

Reduce the concentration of microbes on the skin

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2
Q

Steps to safely wash hands

A
  1. Wet your hands with clean running water and apply soap-use warm water if it is available
  2. Rub hands together to make a lather and scrub all surfaces
  3. Continuing rubbing hands for 20 seconds
  4. Rinse well under running water
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3
Q

When to wash your hands

A

Entering the lab
Leaving the lab
Any time in between

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4
Q

Media can be either a broth or a

A

Agar

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5
Q

Media can be either undefined or

A

Defined

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6
Q

Undefined media

A

The exact ingredients and their amounts are not known

Commercially available and easy to prepare

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7
Q

Defined media

A

All of the ingredients and their amounts are known

Preparation is more complicated and time consuming

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8
Q

Agar originates from

A

Seaweed

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9
Q

Agar is a better solidifier than gelatin because

A

It is firmer/stronger and cannot be degraded by bacteria

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10
Q

What is the most important thing when preparing media?

A

Sterility

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11
Q

The most effective way to sterilize media is by

A

Autoclaving

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12
Q

What are the three parameters critical in obtaining sterility?

A

Temperature
Time
Pressure (from steam)

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13
Q

Why are all three parameters necessary?

A

To kill endospores

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14
Q

How many ways can steam be released from the chamber of an autoclave?

A

2

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15
Q

When is fast exhaust used?

A

Dry items like glassware and certain plastics

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16
Q

When is slow exhaust used?

A

when working with liquids

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17
Q

Autoclave safety requirements are

A

Insulated gloves
Face shield
Slow opening of the door
Cart available to place hot items on

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18
Q

How can you tell whether something has been autoclave and is sterile?

A

Autoclave tape will turn striped

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19
Q

What kind of media is Tryptic Soy

A

Undefined

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20
Q

What parameters are used for autoclaving (specific)

A

20 minutes, 121C, 15 psi

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21
Q

What do aseptic techniques do?

A

Prevent media from becoming contaminated

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22
Q

What are some tools used in aseptic transfers?

A

Inoculating loops and needles
Sterile transfer pipette
Glass spreading stick

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23
Q

Describe the proper flame for a Bunsen burner

A

Inner and outer cone

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24
Q

What is the goal of isolation

A

To obtain a pure bacterial culture from a mixed culture

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25
What happens when the last quadrant streak overlaps with the 1st quadrant streak?
Very few if any well isolated colonies
26
What happens when the loop is not flamed between quadrants?
No isolated colonies
27
What is ubiquity
Existing or being everywhere
28
What types of microorganisms are out there
Pathogenic Opportunistic Pathogens Free-Living Microorganisms
29
Why would you streak an environmental sample differently than a lab sample
Environmental sample will more likely have fewer organisms
30
Environmental Streak
One large zig zag across the entire plate
31
What are the forms a colony can take?
Circular Irregular Filamentous Rhizoids
32
What ways are the elevation of a colony described
``` Raised Convex Flat Umbonate Crateriform ```
33
How are margins defined for colonies?
``` Entire Undulate Filiform Curled Locate ```
34
How can colonies be described?
``` Form Elevation Margin Pigmentation Texture Growth Patterns ```
35
When making a dilution what are important points to remember
Always add the sample to the saline broth Always mix each dilution tube after adding the sample Always change piper tips after each sample transfer
36
Where should you place the bacterial dilution in the agar plate?
The center
37
Colony forming units
Can be calculated when you know the number of colonies at a specific dilution. CFU/mL =#colonies/(dilution factor *volume plated)
38
Biofilm
A complex association that arised from a mixture of microorganisms growing together on the surface of a habitat
39
Stages of biofilm formation
1. Surface conditioning 2. Initial attachment 3. Slime formation 4. Secondary colonization 5. Maturation 6. Dispersal
40
Are bacteria within a biofilm more or less resistant to disinfectants/detergents as well as antibiotics
More
41
What is the media enriched with to help with biofilm formation
Glucose to help with surface conditioning
42
What dye was used to observe the biofilm
Crystal violet
43
What is soil composed of?
40% inorganic material 5% organic material 50% Air and water 5% microorganisms and macroorganism
44
Decomposed plant material lays
Zero to 2 inches into the soil
45
Surface soil
Soil that is 2 to 10 inches and is high in organic matter and microbes
46
Subsoil
10 to 30 inches little organic matter and fewer microbes
47
Soil base
30 to 48 inches with even fewer microbes
48
What roles can microbes play
Carbon cycle - detritivores Nitrogen cycle-denitrifying bacteria, nitrogen fixing root bacteria Sulfur cycle Food web
49
Prokaryotes in Soil
Bacteria
50
Eukaryotes in Soil
Filamentous fungi Protozoan Nematode
51
What types of bacteria are in soil?
``` Chemoautotrophs Decomposers Mutualists Disease suppressors Pathogens ```
52
What do chemoautotrophic bacteria do
``` Oxidize inorganic compounds to yield energy and reduce CO2 Ex. Nitrosamines europaea Nitro so after winogradskyi Thiobacillus Desulfovibrio ```
53
What do bacterial decomposed do?
``` Break down or gain biomass Ex Pseudomonas fluorescens Bacillus subtitles Actinobacteria ```
54
Many members of the actinobacteria group produce?
Antibiotics
55
What are bacterial mutualists?
Bacteria that form partnerships with plants Ex Rhizobium
56
What re disease suppressors
``` Bacterial species that can suppress the occurrence of plant disease by secreting anti-fungal or anti-insecticidal compounds Ex Bacillus Rhizoctonia Bacillus thuringiensis ```
57
What are bacterial pathogens
Bacterial species that can cause disease in plants and/or animals Ex Erwinia Clostridium tetani
58
What types of eukaryotes are in soil
Decomposers Mutualists Pathogens
59
What are fungal decomposers
Species that break down organic biomass Ex Aspergillus Penicillium
60
What are fungal mutualists
Bacteria that form partnerships with plants Ex Mycorrhizal fungi
61
What are fungal pathogens
Fungal species that can cause disease in plants and/or animals Ex Verticillium
62
Nutrient agar promotes the grow of ______ but not _____
Many types of bacteria; fungi
63
Glycerol yeast extract supports the growth of _____ but not enough to support_______ or _______
Actinobacteria; simple bacteria; fungi
64
Sabouraud Dextrose Agar with antibiotics will allow _____to grow but not ______
Fungi, bacteria
65
What kind of viruses cannot be worked on in this lab?
Animal Working with animal viruses requires a high level of sterility Work must be done in biosafety cabinets that have a filtered air supply
66
What is a bacteriophage?
Viruses that only infect bacteria
67
Bacteriophage require a host _______ in which to replicate because they do not have _______,_________ etc, and use the cellular_______ of its host. They contain ______ and are ________ in structure.
Bacteria; enzymes; ribosomes; machinery; DNA; complex
68
Animal viruses require a host _____cell and use the cellular________of its host. They contain _____or_____but never both and are _______in structure.
Eukaryotic; machinery;DNA;RNA;simple
69
A bacteria phage consists of
Caps is or head with dna inside Sheath Tail fibers
70
Animal viruses contain
Capsid with DNA
71
Phases of bacteriophage infection
``` Attachment Penetration Synthesis Assembly Release ```
72
Why is soft agar used for plaque assays?
Bacteria cannot move through it but bacteriophage can move short distances
73
What is a plaque
The area of clearing on the bacterial lawn.
74
How do you calculate PFU/mL
#of plaque/(dilution factor * ml of Phage added to e. Coil)
75
Can different phage produce different looking plaques?
Yes
76
How many sets of lenses does a compound microscope have?
2
77
How many hands should be used when carrying a microscope?
2
78
Before you turn on the microscope check the ____ ______.
Lamp control
79
What 4 objectives are there?
4x 10x 40x 100x
80
What is the magnification of the ocular lens?
10x
81
What is a condensor?
The piece that narrows the beam of light that strikes the specimen
82
What must be used when viewing specimen under the 100x objective?
Immersion oil
83
Why must immersion oil be used with the 100x objective lens?
It prevents the light from being refracted.
84
List types of microorganisms
``` Viruses. Helminths Bacteria Archaea Fungi Algae Protozoa ```
85
Viruses can only be seen using a ______microscope
Electron
86
Most bacteria and archaea can be seen by a light microscope using ______ ________ and the aid of ________.
Oil immersion; staining
87
Bacteria that do not require staining
``` Cyanobacteria because of photosynthetic pigments Ex Gloeocapsa Anabaena Oscillatoria ```
88
Aquatic fungi are from the class
Chytridiomycetes
89
Types of algae in freshwater
``` Chlorella Ulothrix Spirogyra Diatoms or phytoplankton Navicula Synedra Cocconeis ```
90
Protozoa include
Euglenids - green flagellated photosynthetic Protozoa Dinoflagellates - flagellated Protozoa Ciliates - use cilia for locomotion Sarcodina- use pseudopods for locomotion
91
Helminths include
Nematodes-unsegmented with a full digestive tract
92
When using a slide cover which objective should you not use?
100X
93
Fungi can be ______ or _______
Macroscopic; microscopic
94
Microscopic fungi have two basic morphological types which are
Yeasts and Molds
95
General characteristics of yeasts
Grow in colonies that are very similar in appearance to bacterial colonies Yeast cells are round or oval in shape Reproduce by budding
96
Example of yeast
Candida albicans - oral thrush - opportunistic pathogen
97
General characteristics of molds
Grow as hyphae (long thread-like cells) Hyphae can be septate(divided by cell walls) or nonseptate(a continuous cell) and vegetative or reproductive. Primary mode of reproduction is by asexual spore formation Asexual spore types Nicole sporangiospores (enclosed) and condidospores (free) Sexual spore formation is some molds involves production of zygospores
98
Examples of mold
Rhizopus- includes common bread mold-sporangium, nonseptate, form zygospore Aspergillus - opportunistic pathogen, septate, conidiophores Penicillium - produces penicillin, septate, conidiophores
99
Why do stains need to be used to view most bacteria?
Cytoplasm is transparent
100
What is a stain?
A solution in which a dye or chromogen has been added to a liquid
101
A chromogen consists of __ components. The _____ and the _____.
2; chromosphore; auxochrome
102
The _____ is carried by the auxochrome and determines whether a or not a stain will adhere to a bacterium
Charge Can be positive or negative depending on the charge carried by the auxochrome
103
Bacteria have a ______charge on their cell surface
Negative
104
A Positive stain has a _______charge so the _______ binds to the bacterial cell surface.
Positive; auxochrome The bacteria is stained & background is white
105
With a negative stain, the auxochrome has a ________ charge which ______ and the _________ cannot bind to the bacterial cell surface.
Negative; repel; auxochrome Bacteria left colorless and background is stained.
106
Examples of Positive Stains
Crystal violet Methylene blue Safranin
107
Examples of negative stains
India Ink | Nigrosin
108
Positive stains require ____ fixing; negative stains do not.
Heat
109
What are the pros to simple and negative stains?
Only require 1 dye (uncomplicated)
110
What are the cons of simple and negative stains
They cannot differentiate unique cell structures or features between bacteria.
111
All negative stained slides must be _______ in the ______ _______.
Discarded; bleach bucket
112
What are the three general shapes of bacteria?
Bacillus (rods) Coccus (spheres) Spirillus (spiral)
113
What are some types of arrangement?
Singles or pairs Chains Clusters of cocci Palisades of bacilli
114
What is pleomorphism
Slight deviations in the overall shape and/or size of a bacteria
115
Who invented gram staining?
Christian Gram
116
What makes the gram stain so important?
It can differentiate between bacteria
117
Gram ______ cells have a thick layer of peptidoglycan; Gram ______ cells have a thin layer of peptidoglycan and an outer membrane.
Positive; Negative
118
Gram staining requires ________ fixation
Heat
119
What is the primary stain in gram staining?
Crystal violet
120
The mordant used is _______ and produces _______-_________ complexes
Iodine;crystal violet;iodine
121
What decolorizer is used?
Ethanol
122
How does the decolorizer work?
Dissolves the lipids in the outer membrane
123
What counterstain is used?
Safranin
124
What bacteria does gram staining not work on?
Nocardia and Mycobacterium
125
What color is a gram positive bacteria?
Purple
126
What color is an acid fast stain positive?
Pink
127
What do acid fast positive bacteria have in their cell walls?
Mycolic acid (waxy lipid)
128
Example of a Mycobacterium
Mycobacterium tuberculosis Highly communicable 1/3 of the world is infected with it Leading killer of hiv infected individuals 4.2/100000 people in the US
129
Can acid-fast non-pathogenic mycobacterium and nocardia species exist in the environment?
Yes
130
what is the primary stain in acid fast staining?
Carbolfuchsin | Phenol based that is lipid soluble
131
Carbolfuchsin stain can be enhanced by what two methods?
Applying heat to drive the steam in (steam) Increase the concentration of phenol
132
If heat is used in the staining procedure, which method is it?
Ziehl-neelsen
133
If a higher concentration of phenol is used in the carbolfuchsin stain which method is it?
Kinyoun Method
134
What is a capsule?
A complex layer of sugars and proteins that tightly surrounds a bacterium
135
Capsule Staining is a _______stain.
Differential
136
What is the role of the capsule?
Protection against environmental conditions and dehydration Adherence to surfaces Prevents phagocytosis
137
In a pathogenic bacterial species a capsule is considered a ______ ______.
Virulence factor
138
Can non pathogenic bacteria possess capsules?
Yes
139
Examples of capsule bacteria
Neisseria menigitidis | Many bacillus species including those found in the soil bacillus megaterium, bacillus licheniformis
140
Can a capsule be stained?
No
141
Why wont a capsule stain?
It is water soluble
142
The capsule stain is a differential stain that combines ______ and _____ stains.
Negative; simple
143
Congo red is an ______ dye (ie. it carries a ________charge)
Acidic; negative
144
In a negative stain only the ______ will be stained
Background
145
A capsule stain slide is never _____ _______.
Heat fixed.
146
What is the simple stain used in capsule staining?
Maneval’s stain
147
Maneval’s stain is a ______ dye with a _____ charge.
Basic; positive
148
Capsule stain slides must be discarded in the ______ _______
Bleach; bucket
149
To overcome this constant flux of nutrients in the environment, some bacteria have the capacity to produce _____ ______ or ________.
Inclusion bodies; granules
150
Poly B-hyroxybutyrate (PHB) is an _____ _____ _____
Inclusion body stain
151
If a bacterium is in a nutrient rich environment, it is likely to contain ______ or ______ inclusions
More; larger
152
Why produce inclusion bodies?
Nutrient reservoir Avoid lyse from an increase in osmotic pressure
153
Do all bacteria produce inclusion bodies?
No
154
Carboxysomes are an ________ that continue the enzyme _______.
Inclusion; ribulose 1,5-diphosphate carboxylase
155
Types of inclusions:
Suffer Granules (Thiobacillus) Carboxysomes Polysaccharide Granules - contain glycogen/starch Metachromatic granules - volutin (inorganic phosphates) for ATP Corynebacterium diphtheria is a metachromatic granules that causes diphtheria Magnetosomes contain iron oxide which can act like tiny magnets Lipid inclusions contain PHB poly B-hyroxybutyrate used as both carbon and energy sources
156
PHB consists of
B-hyroxybutyrate molecules linked by an ester bond between carboxyl group of one an the hydroxyl group of the next Hydrolysis of the ester bound results in carbon containing molecules and sufficient free energy to be harnessed for atp
157
PHB Inclusions range in diameter from ____ to ____
0.2; 0.7
158
PHB inclusions are contained within a unique membrane that is composed of a _______ lipid layer
Single
159
Can all bacteria contain PHB inclusion?
No
160
What is the primary stain of PHB?
Sudan Black B
161
Sudan Black B is a ______ soluble stain that is ______
Lipid; neutral
162
The PHB counterstain is
Safranin
163
Certain bacteria can survive in extremely unfavorable conditions by forming _______
Endospores
164
Endospores is able to withstand extreme ______, ________, ________, and _______ ________.
Temperature; disinfectants; desiccation; and UV radiation
165
Major characteristics of endospores
Contain dna but are inactive metabolically (dormant) Consist of a very tough outer cell coat, a cortex, and an inner core (3 C’s)
166
What are the 3 C’s
Coat, cortex, Core
167
Only a few species can form endospores; two of which are _______ and _______
Bacillus; Clostridium Mostly non pathogenic however bacillus antracis causes anthrax in humans and clostridium tetani cause tetanus and clostridium botulinum cause botulism.
168
The _____, ______, and ________ of the endospores within a bacterium can help in the identification of the organism.
Size; shape; location
169
What is the primary dye in endospores staining?
Malachite green
170
Does endospores staining use steam to drive the stain into the bacteria?
Yes
171
What is the counter stain in endospore staining?
Safranin
172
Flagella may contribute to the _______ of a bacterium since it can allow the bacterium to move to its preferred anatomical site to start the disease process.
Virulence
173
What are two ways to determine whether a bacterium is motile?
Hanging drop slide Semi-solid motility agar
174
The different arrangements of flagella
``` Monotrichous = 1 flagella at 1 pole Lophotrichous = several flagella at 1 pole Amphitrichous = 1 flagella at each pole Peritrichous = flagella all over ```
175
What is used to thicken the flagella so that it can be seen?
Mordant
176
Flagella are thin and ________
Delicate
177
The mordant is _____ meaning it will stick to the flagella as well as any dust or dirt on the slide
Non-specific
178
What is motility media
A semi solid media which has just enough agar added to produce a media with the consistency of sloppy jello (4x less agar)
179
Motility media is thick enough to allow motile bacteria to move but too thick for __________ bacteria to disperse
Non-motile
180
What is added to the motility media to make a motility test easy to read?
Tetrazolium salt
181
TTC reduces to formazan and ______
HCL
182
Formazan is _____ and ______
Red; insoluble
183
TTC is reduced by _______ ______ bacteria
Metabolically active

Microbiology Lab (3 decks)

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