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Flashcards in Exam I Deck (183)
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1
Q

Antiseptics

A

Reduce the concentration of microbes on the skin

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
3
Q

When to wash your hands

A

Entering the lab
Leaving the lab
Any time in between

4
Q

Media can be either a broth or a

A

Agar

5
Q

Media can be either undefined or

A

Defined

6
Q

Undefined media

A

The exact ingredients and their amounts are not known

Commercially available and easy to prepare

7
Q

Defined media

A

All of the ingredients and their amounts are known

Preparation is more complicated and time consuming

8
Q

Agar originates from

A

Seaweed

9
Q

Agar is a better solidifier than gelatin because

A

It is firmer/stronger and cannot be degraded by bacteria

10
Q

What is the most important thing when preparing media?

A

Sterility

11
Q

The most effective way to sterilize media is by

A

Autoclaving

12
Q

What are the three parameters critical in obtaining sterility?

A

Temperature
Time
Pressure (from steam)

13
Q

Why are all three parameters necessary?

A

To kill endospores

14
Q

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

A

2

15
Q

When is fast exhaust used?

A

Dry items like glassware and certain plastics

16
Q

When is slow exhaust used?

A

when working with liquids

17
Q

Autoclave safety requirements are

A

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

18
Q

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

A

Autoclave tape will turn striped

19
Q

What kind of media is Tryptic Soy

A

Undefined

20
Q

What parameters are used for autoclaving (specific)

A

20 minutes, 121C, 15 psi

21
Q

What do aseptic techniques do?

A

Prevent media from becoming contaminated

22
Q

What are some tools used in aseptic transfers?

A

Inoculating loops and needles
Sterile transfer pipette
Glass spreading stick

23
Q

Describe the proper flame for a Bunsen burner

A

Inner and outer cone

24
Q

What is the goal of isolation

A

To obtain a pure bacterial culture from a mixed culture

25
Q

What happens when the last quadrant streak overlaps with the 1st quadrant streak?

A

Very few if any well isolated colonies

26
Q

What happens when the loop is not flamed between quadrants?

A

No isolated colonies

27
Q

What is ubiquity

A

Existing or being everywhere

28
Q

What types of microorganisms are out there

A

Pathogenic
Opportunistic Pathogens
Free-Living Microorganisms

29
Q

Why would you streak an environmental sample differently than a lab sample

A

Environmental sample will more likely have fewer organisms

30
Q

Environmental Streak

A

One large zig zag across the entire plate

31
Q

What are the forms a colony can take?

A

Circular
Irregular
Filamentous
Rhizoids

32
Q

What ways are the elevation of a colony described

A
Raised
Convex
Flat
Umbonate
Crateriform
33
Q

How are margins defined for colonies?

A
Entire
Undulate
Filiform
Curled
Locate
34
Q

How can colonies be described?

A
Form
Elevation
Margin
Pigmentation
Texture
Growth Patterns
35
Q

When making a dilution what are important points to remember

A

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
Q

Where should you place the bacterial dilution in the agar plate?

A

The center

37
Q

Colony forming units

A

Can be calculated when you know the number of colonies at a specific dilution. CFU/mL =#colonies/(dilution factor *volume plated)

38
Q

Biofilm

A

A complex association that arised from a mixture of microorganisms growing together on the surface of a habitat

39
Q

Stages of biofilm formation

A
  1. Surface conditioning
  2. Initial attachment
  3. Slime formation
  4. Secondary colonization
  5. Maturation
  6. Dispersal
40
Q

Are bacteria within a biofilm more or less resistant to disinfectants/detergents as well as antibiotics

A

More

41
Q

What is the media enriched with to help with biofilm formation

A

Glucose to help with surface conditioning

42
Q

What dye was used to observe the biofilm

A

Crystal violet

43
Q

What is soil composed of?

A

40% inorganic material
5% organic material
50% Air and water
5% microorganisms and macroorganism

44
Q

Decomposed plant material lays

A

Zero to 2 inches into the soil

45
Q

Surface soil

A

Soil that is 2 to 10 inches and is high in organic matter and microbes

46
Q

Subsoil

A

10 to 30 inches little organic matter and fewer microbes

47
Q

Soil base

A

30 to 48 inches with even fewer microbes

48
Q

What roles can microbes play

A

Carbon cycle - detritivores
Nitrogen cycle-denitrifying bacteria, nitrogen fixing root bacteria
Sulfur cycle
Food web

49
Q

Prokaryotes in Soil

A

Bacteria

50
Q

Eukaryotes in Soil

A

Filamentous fungi
Protozoan
Nematode

51
Q

What types of bacteria are in soil?

A
Chemoautotrophs
Decomposers
Mutualists
Disease suppressors
Pathogens
52
Q

What do chemoautotrophic bacteria do

A
Oxidize inorganic compounds to yield energy and reduce CO2
Ex.
Nitrosamines europaea
Nitro so after winogradskyi
Thiobacillus 
Desulfovibrio
53
Q

What do bacterial decomposed do?

A
Break down or gain biomass
Ex
Pseudomonas fluorescens
Bacillus subtitles
Actinobacteria
54
Q

Many members of the actinobacteria group produce?

A

Antibiotics

55
Q

What are bacterial mutualists?

A

Bacteria that form partnerships with plants
Ex
Rhizobium

56
Q

What re disease suppressors

A
Bacterial species that can suppress the occurrence of plant disease by secreting anti-fungal or anti-insecticidal compounds
Ex
Bacillus
Rhizoctonia
Bacillus thuringiensis
57
Q

What are bacterial pathogens

A

Bacterial species that can cause disease in plants and/or animals
Ex
Erwinia
Clostridium tetani

58
Q

What types of eukaryotes are in soil

A

Decomposers
Mutualists
Pathogens

59
Q

What are fungal decomposers

A

Species that break down organic biomass
Ex
Aspergillus
Penicillium

60
Q

What are fungal mutualists

A

Bacteria that form partnerships with plants
Ex
Mycorrhizal fungi

61
Q

What are fungal pathogens

A

Fungal species that can cause disease in plants and/or animals
Ex
Verticillium

62
Q

Nutrient agar promotes the grow of ______ but not _____

A

Many types of bacteria; fungi

63
Q

Glycerol yeast extract supports the growth of _____ but not enough to support_______ or _______

A

Actinobacteria; simple bacteria; fungi

64
Q

Sabouraud Dextrose Agar with antibiotics will allow _____to grow but not ______

A

Fungi, bacteria

65
Q

What kind of viruses cannot be worked on in this lab?

A

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
Q

What is a bacteriophage?

A

Viruses that only infect bacteria

67
Q

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.

A

Bacteria; enzymes; ribosomes; machinery; DNA; complex

68
Q

Animal viruses require a host _____cell and use the cellular________of its host. They contain _____or_____but never both and are _______in structure.

A

Eukaryotic; machinery;DNA;RNA;simple

69
Q

A bacteria phage consists of

A

Caps is or head with dna inside
Sheath
Tail fibers

70
Q

Animal viruses contain

A

Capsid with DNA

71
Q

Phases of bacteriophage infection

A
Attachment
Penetration
Synthesis
Assembly
Release
72
Q

Why is soft agar used for plaque assays?

A

Bacteria cannot move through it but bacteriophage can move short distances

73
Q

What is a plaque

A

The area of clearing on the bacterial lawn.

74
Q

How do you calculate PFU/mL

A

of plaque/(dilution factor * ml of Phage added to e. Coil)

75
Q

Can different phage produce different looking plaques?

A

Yes

76
Q

How many sets of lenses does a compound microscope have?

A

2

77
Q

How many hands should be used when carrying a microscope?

A

2

78
Q

Before you turn on the microscope check the ____ ______.

A

Lamp control

79
Q

What 4 objectives are there?

A

4x
10x
40x
100x

80
Q

What is the magnification of the ocular lens?

A

10x

81
Q

What is a condensor?

A

The piece that narrows the beam of light that strikes the specimen

82
Q

What must be used when viewing specimen under the 100x objective?

A

Immersion oil

83
Q

Why must immersion oil be used with the 100x objective lens?

A

It prevents the light from being refracted.

84
Q

List types of microorganisms

A
Viruses.       Helminths
Bacteria
Archaea
Fungi
Algae
Protozoa
85
Q

Viruses can only be seen using a ______microscope

A

Electron

86
Q

Most bacteria and archaea can be seen by a light microscope using ______ ________ and the aid of ________.

A

Oil immersion; staining

87
Q

Bacteria that do not require staining

A
Cyanobacteria because of photosynthetic pigments
Ex
Gloeocapsa
Anabaena 
Oscillatoria
88
Q

Aquatic fungi are from the class

A

Chytridiomycetes

89
Q

Types of algae in freshwater

A
Chlorella 
Ulothrix
Spirogyra 
Diatoms or phytoplankton
        Navicula 
         Synedra 
          Cocconeis
90
Q

Protozoa include

A

Euglenids - green flagellated photosynthetic Protozoa
Dinoflagellates - flagellated Protozoa
Ciliates - use cilia for locomotion
Sarcodina- use pseudopods for locomotion

91
Q

Helminths include

A

Nematodes-unsegmented with a full digestive tract

92
Q

When using a slide cover which objective should you not use?

A

100X

93
Q

Fungi can be ______ or _______

A

Macroscopic; microscopic

94
Q

Microscopic fungi have two basic morphological types which are

A

Yeasts and Molds

95
Q

General characteristics of yeasts

A

Grow in colonies that are very similar in appearance to bacterial colonies

Yeast cells are round or oval in shape

Reproduce by budding

96
Q

Example of yeast

A

Candida albicans - oral thrush - opportunistic pathogen

97
Q

General characteristics of molds

A

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
Q

Examples of mold

A

Rhizopus- includes common bread mold-sporangium, nonseptate, form zygospore

Aspergillus - opportunistic pathogen, septate, conidiophores

Penicillium - produces penicillin, septate, conidiophores

99
Q

Why do stains need to be used to view most bacteria?

A

Cytoplasm is transparent

100
Q

What is a stain?

A

A solution in which a dye or chromogen has been added to a liquid

101
Q

A chromogen consists of __ components. The _____ and the _____.

A

2; chromosphore; auxochrome

102
Q

The _____ is carried by the auxochrome and determines whether a or not a stain will adhere to a bacterium

A

Charge

Can be positive or negative depending on the charge carried by the auxochrome

103
Q

Bacteria have a ______charge on their cell surface

A

Negative

104
Q

A Positive stain has a _______charge so the _______ binds to the bacterial cell surface.

A

Positive; auxochrome

The bacteria is stained & background is white

105
Q

With a negative stain, the auxochrome has a ________ charge which ______ and the _________ cannot bind to the bacterial cell surface.

A

Negative; repel; auxochrome

Bacteria left colorless and background is stained.

106
Q

Examples of Positive Stains

A

Crystal violet
Methylene blue
Safranin

107
Q

Examples of negative stains

A

India Ink

Nigrosin

108
Q

Positive stains require ____ fixing; negative stains do not.

A

Heat

109
Q

What are the pros to simple and negative stains?

A

Only require 1 dye (uncomplicated)

110
Q

What are the cons of simple and negative stains

A

They cannot differentiate unique cell structures or features between bacteria.

111
Q

All negative stained slides must be _______ in the ______ _______.

A

Discarded; bleach bucket

112
Q

What are the three general shapes of bacteria?

A

Bacillus (rods)
Coccus (spheres)
Spirillus (spiral)

113
Q

What are some types of arrangement?

A

Singles or pairs
Chains
Clusters of cocci
Palisades of bacilli

114
Q

What is pleomorphism

A

Slight deviations in the overall shape and/or size of a bacteria

115
Q

Who invented gram staining?

A

Christian Gram

116
Q

What makes the gram stain so important?

A

It can differentiate between bacteria

117
Q

Gram ______ cells have a thick layer of peptidoglycan; Gram ______ cells have a thin layer of peptidoglycan and an outer membrane.

A

Positive; Negative

118
Q

Gram staining requires ________ fixation

A

Heat

119
Q

What is the primary stain in gram staining?

A

Crystal violet

120
Q

The mordant used is _______ and produces _______-_________ complexes

A

Iodine;crystal violet;iodine

121
Q

What decolorizer is used?

A

Ethanol

122
Q

How does the decolorizer work?

A

Dissolves the lipids in the outer membrane

123
Q

What counterstain is used?

A

Safranin

124
Q

What bacteria does gram staining not work on?

A

Nocardia and Mycobacterium

125
Q

What color is a gram positive bacteria?

A

Purple

126
Q

What color is an acid fast stain positive?

A

Pink

127
Q

What do acid fast positive bacteria have in their cell walls?

A

Mycolic acid (waxy lipid)

128
Q

Example of a Mycobacterium

A

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
Q

Can acid-fast non-pathogenic mycobacterium and nocardia species exist in the environment?

A

Yes

130
Q

what is the primary stain in acid fast staining?

A

Carbolfuchsin

Phenol based that is lipid soluble

131
Q

Carbolfuchsin stain can be enhanced by what two methods?

A

Applying heat to drive the steam in (steam)

Increase the concentration of phenol

132
Q

If heat is used in the staining procedure, which method is it?

A

Ziehl-neelsen

133
Q

If a higher concentration of phenol is used in the carbolfuchsin stain which method is it?

A

Kinyoun Method

134
Q

What is a capsule?

A

A complex layer of sugars and proteins that tightly surrounds a bacterium

135
Q

Capsule Staining is a _______stain.

A

Differential

136
Q

What is the role of the capsule?

A

Protection against environmental conditions and dehydration
Adherence to surfaces
Prevents phagocytosis

137
Q

In a pathogenic bacterial species a capsule is considered a ______ ______.

A

Virulence factor

138
Q

Can non pathogenic bacteria possess capsules?

A

Yes

139
Q

Examples of capsule bacteria

A

Neisseria menigitidis

Many bacillus species including those found in the soil bacillus megaterium, bacillus licheniformis

140
Q

Can a capsule be stained?

A

No

141
Q

Why wont a capsule stain?

A

It is water soluble

142
Q

The capsule stain is a differential stain that combines ______ and _____ stains.

A

Negative; simple

143
Q

Congo red is an ______ dye (ie. it carries a ________charge)

A

Acidic; negative

144
Q

In a negative stain only the ______ will be stained

A

Background

145
Q

A capsule stain slide is never _____ _______.

A

Heat fixed.

146
Q

What is the simple stain used in capsule staining?

A

Maneval’s stain

147
Q

Maneval’s stain is a ______ dye with a _____ charge.

A

Basic; positive

148
Q

Capsule stain slides must be discarded in the ______ _______

A

Bleach; bucket

149
Q

To overcome this constant flux of nutrients in the environment, some bacteria have the capacity to produce _____ ______ or ________.

A

Inclusion bodies; granules

150
Q

Poly B-hyroxybutyrate (PHB) is an _____ _____ _____

A

Inclusion body stain

151
Q

If a bacterium is in a nutrient rich environment, it is likely to contain ______ or ______ inclusions

A

More; larger

152
Q

Why produce inclusion bodies?

A

Nutrient reservoir

Avoid lyse from an increase in osmotic pressure

153
Q

Do all bacteria produce inclusion bodies?

A

No

154
Q

Carboxysomes are an ________ that continue the enzyme _______.

A

Inclusion; ribulose 1,5-diphosphate carboxylase

155
Q

Types of inclusions:

A

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
Q

PHB consists of

A

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
Q

PHB Inclusions range in diameter from ____ to ____

A

0.2; 0.7

158
Q

PHB inclusions are contained within a unique membrane that is composed of a _______ lipid layer

A

Single

159
Q

Can all bacteria contain PHB inclusion?

A

No

160
Q

What is the primary stain of PHB?

A

Sudan Black B

161
Q

Sudan Black B is a ______ soluble stain that is ______

A

Lipid; neutral

162
Q

The PHB counterstain is

A

Safranin

163
Q

Certain bacteria can survive in extremely unfavorable conditions by forming _______

A

Endospores

164
Q

Endospores is able to withstand extreme ______, ________, ________, and _______ ________.

A

Temperature; disinfectants; desiccation; and UV radiation

165
Q

Major characteristics of endospores

A

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
Q

What are the 3 C’s

A

Coat, cortex, Core

167
Q

Only a few species can form endospores; two of which are _______ and _______

A

Bacillus; Clostridium

Mostly non pathogenic however bacillus antracis causes anthrax in humans and clostridium tetani cause tetanus and clostridium botulinum cause botulism.

168
Q

The _____, ______, and ________ of the endospores within a bacterium can help in the identification of the organism.

A

Size; shape; location

169
Q

What is the primary dye in endospores staining?

A

Malachite green

170
Q

Does endospores staining use steam to drive the stain into the bacteria?

A

Yes

171
Q

What is the counter stain in endospore staining?

A

Safranin

172
Q

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.

A

Virulence

173
Q

What are two ways to determine whether a bacterium is motile?

A

Hanging drop slide

Semi-solid motility agar

174
Q

The different arrangements of flagella

A
Monotrichous = 1 flagella at 1 pole
Lophotrichous = several flagella at 1 pole
Amphitrichous = 1 flagella at each pole
Peritrichous = flagella all over
175
Q

What is used to thicken the flagella so that it can be seen?

A

Mordant

176
Q

Flagella are thin and ________

A

Delicate

177
Q

The mordant is _____ meaning it will stick to the flagella as well as any dust or dirt on the slide

A

Non-specific

178
Q

What is motility media

A

A semi solid media which has just enough agar added to produce a media with the consistency of sloppy jello (4x less agar)

179
Q

Motility media is thick enough to allow motile bacteria to move but too thick for __________ bacteria to disperse

A

Non-motile

180
Q

What is added to the motility media to make a motility test easy to read?

A

Tetrazolium salt

181
Q

TTC reduces to formazan and ______

A

HCL

182
Q

Formazan is _____ and ______

A

Red; insoluble

183
Q

TTC is reduced by _______ ______ bacteria

A

Metabolically active