microbiology ch 3 Flashcards
1
Q
What are two units typically used to measure microorganisms?
A
Micrometers and nanometers
2
Q
What are micrometers and nanometers typically used to measure?
A
Very small objects, such as microorganisms
3
Q
How many nanometers are in one micrometer?
A
1000 nm = 1 um
4
Q
1 nanometer equals how many micrometers?
A
0.001 um
5
Q
How many lenses does a simple microscope have?
A
1
6
Q
What distinguishes a simple microscope from a magnifying glass?
A
Higher magnification lens
7
Q
This type of microscope only has 1 lens
A
Simple microscope
8
Q
How many lenses are in a compound microscope?
A
2
9
Q
How is total magnification of a compound microscope calculated?
A
Objective lens x ocular lens
10
Q
This type of microscope has an objective lens and an ocular lens
A
Compound microscope
11
Q
Objective lens x ocular lens = ?
A
Total magnification of a compound microscope
12
Q
What are the two types of lens in a compound microscope?
A
Objective lens and ocular lens
13
Q
What are the five steps of movement of a light ray in a compound light microscope?
A
- Illuminator; 2. Condenser; 3. Specimen; 4. Objective lenses; 5. Ocular lens
14
Q
What is resolution?
A
Ability of lenses to distinguish two points
15
Q
If a microscope has a resolving power of 0.4 nm, how far apart can it distinguish two points?
A
0.4 nm
16
Q
What type of wavelengths of light provide greater resolution?
A
Shorter wavelengths
17
Q
What is the ability of lenses to distinguish two points?
A
Resolution
18
Q
Do shorter wavelengths of light provide lower resolution?
A
No
19
Q
What is the refractive index?
A
Measure of the light-bending ability of a medium
20
Q
Can a specimen refract light enough so that it does not pass through an object lens?
A
Yes
21
Q
What is used to keep light from refracting?
A
Immersion oil
22
Q
What is the the measure of light-bending ability of a medium?
A
Refractive index
23
Q
What is the purpose of immersion oil?
A
To keep light from refracting
24
Q
What type of objects are visible against a bright background in brightfield illumination?
A
Dark objects
25
Does light reflected off the specimen enter the objective lens in brightfield illumination?
No
26
This type of compound light microscopy shows dark objects against a bright background
Brightfield illumination
27
In darkfield microscopy, what type of objects are visible against a dark background?
Light objects
28
What is placed in the condenser in darkfield microscopy?
Opaque disk
29
Is light reflected from the specimen the only light to enter the objective lens in darkfield microscopy?
Yes
30
This type of microscopy uses light objects visible against a dark background
Darkfield microscopy
31
Where is the opaque disk placed in darkfield microscopy?
In the condenser
32
What is the only light to enter the lens in darkfield microscopy?
Light reflected from the specimen
33
Does phase-contrast microscopy allow examination of living organisms and internal cell structure?
Yes
34
What two sets of light rays does phase-contrast microscopy combine to form an image?
Direct rays and diffracted rays
35
What two types of microscopy does phase-contrast microscopy combine?
Brightfield and darkfield
36
This type of microscopy allows for examination of living organisms
Phase-contrast microscopy
37
This type of microscopy uses direct and diffracted rays to form an image
Phase-contrast microscopy
38
This type of microscopy uses a combination of brightfield and darkfield
Phase-contrast microscopy
39
This type of microscopy, similar to phase-contrast microscopy, uses two light beams and prisms to split light beams
Differential interference contrast microscopy
40
Specimens in this type of microscopy appear three-dimensional and brightly colored
Differential interference contrast microscopy
41
Do specimens in brightfield microscopy appear three-dimensional and brightly colored?
No
42
Does differential interference contrast microscopy show contrast and color of the specimen?
Yes
43
Are differential interference contrast microscopy and phase-contrast microscopy similar?
Yes
44
What type of light does fluorescence microscopy use?
UV light
45
What type of light do fluorescent substances emit in fluorescence microscopy?
Visible light
46
This type of light microscopy may use cells stained with fluorescent dyes
Fluorescence microscopy
47
This type of microscopy can be used to detect pathogens within cells, tissues, or other clinical specimens
Fluorescence microscopy
48
This type of microscopy uses UV light
Fluorescence microscopy
49
This type of substances absorb UV and emit visible light
Fluorescent substances
50
What is another word for fluorescent dyes?
Fluorochromes
51
This type of microscopy uses a beam of electrons passing through ultrathin sections of a specimen
Transmission electron microscopy
52
Can specimens in transmission electron microscopy be stained with heavy metal salts for contrast?
Yes
53
What is a specimen placed on in transmission electron microscopy?
Copper mesh
54
What is the range of magnification for transmission electron microscopy?
10,000 to 10,000,000x
55
What is the resolution of transmission electron microscopy?
10pm
56
This type of microscopy may use specimens stained with heavy metal salts
Transmission electron microscopy
57
This type of microscopy can magnify up to 10,000,000x
Transmission electron microscopy
58
Specimens in this type of microscopy are placed on a copper mesh grid instead of a glass slide
Transmission electron microscopy
59
What does transmission electron microscopy use?
A beam of electrons passing through ultrathin sections of a specimen, then through an electromagnetic lens, then focused onto a projector lens
60
This type of microscopy uses an electron gun to produce a beam of electrons that scan the surface of a specimen
Scanning electron microscopy
61
Can scanning electrons only produce a two-dimensional image?
No
62
What is the range of magnification of scanning electron microscopy?
1,000 - 500,000x
63
What resolution is scanning electron microscopy capable of achieving?
10nm
64
This type of microscopy uses secondary electrons emitted from the specimen to produce a three-dimensional image
Scanning electron microscopy
65
This type of microscopy can magnify an object up to 500,000x
Scanning electron microscopy
66
This type of microscopy can achieve a resolution of 10nm
Scanning electron microscopy
67
This type of microscopy uses various probes to examine the surface of a specimen using electric currents
Scanned-probe microscopy
68
Does scanned-probe microscopy modify the specimen or expose it to damaging, high-energy radiation?
No
69
This type of microscopy is used to map atomic and molecular shapes, characterize magnetic and chemical properties, and to determine temperature variations inside cells
Scanned-probe microscopy
70
This type of microscopy can be used to map atomic and molecular shapes
Scanned-probe microscopy
71
Can scanned-probe microscopy be used to determine temperature variations inside cells?
Yes
72
This type of microscopy can be used to characterize magnetic and chemical properties
Scanned-probe microscopy
73
Does scanned-probe microscopy pass a beam of electrons through a specimen?
No
74
This type of microscopy uses short-wavelength (blue) light to excite a single plane of a spectrum
Confocal microscopy
75
This type of microscopy illuminates each plane of a specimen and constructs a three-dimensional image
Confocal microscopy
76
This type of microscopy can examine layers of cells to a depth of 100um
Confocal microscopy
77
What type of light does confocal microscopy use?
Short-wavelength light (blue)
78
Can confocal microscopy construct a three-dimensional image of a specimen?
Yes
79
To what depth of cell layers can confocal microscopy examine?
Up to 100um
80
Does confocal microscopy use fluorochrome dyes?
Yes
81
Does two-photon microscopy use fluorochrome dyes?
Yes
82
This type of microscopy uses two photons of long-wavelength (red) light to excite fluorochrome dyes
Two-photon microscopy
83
This type of microscopy can study living cells up to 1 mm deep
Two-photon microscopy
84
What type of light does two-photon microscopy use?
Long-wavelength light (red)
85
How deep can two-photon microscopy study living cells?
1 mm
86
This type of microscopy uses two laser beams; one to stimulate glowing of fluorescent molecules, the other to cancel all fluorescence except for that in one nm
Super-resolution light microscopy
87
This type of microscopy scans the specimen nm by nm, then puts the images together
Super-resolution light microscopy
88
This type of microscopy can use cells stained with fluorescent dyes that are specific to certain molecules
Super-resolution light microscopy
89
How many laser beams does super-resolution light microscopy use?
2
90
What do each of the lasers in super-resolution light microscopy do?
One stimulates fluorescent molecules to glow
91
What do each of the lasers in super-resolution light microscopy do?
One stimulates fluorescent molecules to glow, while the other cancels all fluorescence except for that in one nm
92
This type of microscopy uses sound waves to reflect off specimens
Scanning acoustic microscopy
93
This type of microscopy is used to study cells attached to surfaces
Scanning acoustic microscopy
94
This type of microscopy has a resolution of 1 um
Scanning acoustic microscopy
95
What type of waves does scanning acoustic microscopy use?
Sound waves
96
What type of cells is scanning acoustic microscopy used to study?
Cells attached to surfaces
97
What is the resolution of scanning acoustic microscopy?
1 um
98
Does electron microscopy result in greater resolutions than light microscopy?
Yes
99
What type of specimen is electron microscopy necessary to observe?
Very small specimens, such as viruses
100
This type of microscopy uses a tungsten probe to scan a specimen and reveal details of its surface
Scanning tunneling microscopy
101
This type of microscopy has a resolution of 1/100 of an atom
Scanning tunneling microscopy
102
What type of probe does scanning tunneling microscopy use?
Tungsten probe
103
What is the resolution of scanning tunneling microscopy?
1/100 of an atom
104
This type of microscopy uses a metal-and-diamond probe placed onto a specimen
Atomic force microscopy
105
This type of microscopy can produce images at near-atomic level
Atomic force microscopy
106
What type of probe does atomic force microscopy use?
Metal-and-diamond probe
107
What is the resolution of atomic force microscopy?
Near-atomic level
108
What is staining?
Coloring microorganisms with a dye that emphasizes certain structure
109
What is a smear?
Thin film of material containing microorganisms spread over a slide
110
What happens to microorganisms when they are fixed to the slide?
They are killed
111
Do live/unstained specimens have a great deal of contrast with the surrounding medium?
No
112
What are live specimens used to study?
Cell behavior
113
What is the process of coloring microorganisms with dyes to emphasize certain structures?
Staining
114
What is a thin film of material containing microorganisms spread over a slide?
Smear
115
What type of specimens have little contrast with the surrounding medium?
Live/unstained specimens
116
This type of specimen is used to study cell behavior
Live specimen
117
What do stains consist of?
A positive and negative ion
118
What is a chromophore?
A colored ion in a stain
119
In a basic dye, is the chromophore a cation or anion?
Cation
120
In an acidic dye, is the chromophore a cation or anion?
Anion
121
What is the term for staining the background instead of the cell?
Negative staining
122
What consist of a positive and negative ion, one of which is colored?
Stains
123
Cation chromophores are found in what type of dye?
Basic dye
124
Anion chromophores are found in what type of dye?
Acidic dye
125
What is negative staining?
Staining the background instead of the cell
126
What are the three types of staining techniques?
Simple, differential and special
127
What is simple staining?
Use of a single basic dye
128
This type of staining highlights the entire microorganism to visualize cell shapes and structures
Simple stain
129
This may be used to hold the stain or coat the specimen to enlarge it
Mordant
130
What type of staining uses a single basic dye?
Simple stain
131
What does a mordant do?
Holds the stain or coats the specimen to enlarge it
132
What are the two types of differential stains?
Gram stain and acid-fast stain
133
What are differential stains used for?
To distinguish between bacteria
134
This type of staining is used to distinguish between bacteria
Differential stain
135
Gram stain and acid-fast stain are the two types of this type of staining
Differential stain
136
This type of staining classifies bacteria into gram-positive or gram-negative
Gram staining
137
These bacteria have thick peptidoglycan cell walls
Gram-positive bacteria
138
These bacteria have thin peptidoglycan cell walls
Gram-negative bacteria
139
These bacteria have a layer of lipopolysaccharides
Gram-negative bacteria
140
What two types of bacteria does gram staining classify?
Gram-positive and gram-negative
141
What kind of cell walls do gram-positive bacteria have?
Thick peptidoglycan cell walls
142
What are two characteristics of gram-negative bacteria?
Thin peptidoglycan cell walls and a layer of lipopolysaccharides
143
This type of stain binds only to bacteria that have a waxy material in their cell walls
Acid-fast stain
144
Acid-fast staining is used for the identification of which two bacteria?
Mycobacterium and Nocardia
145
What type of bacteria is acid-fast staining used for?
Bacteria with waxy cell walls that aren't decolorized by acid-alcohol
146
Mycobacterium and Nocardia can be identified using what type of staining?
Acid-fast stain
147
What are the three types of special stains?
Capsule stain, endospore stain, and flagella stain
148
What are special stains used for?
To distinguish parts of microorganisms
149
Capsule stain, endospore stain, and flagella stain are examples of which group of stains?
Special stains
150
This group of staining methods is used to distinguish parts of the microorganisms
Special stains
151
What are capsules?
Gelatinous coverings
152
Will capsules accept most dyes?
No
153
What can be used to contrast the background with the capsule and form a halo around the cell?
India ink or nigrosin
154
These are gelatinous coverings that do not accept most dyes
Capsules
155
How can India ink or Nigrosin be used to look at bacteria capsules?
By suspending them so they contrast the background with the capsule and cause it to look like a halo around the cell
156
What are endospores?
Resistant, dormant structures inside some cells
157
Can endospores be stained by ordinary methods?
No
158
What are the three steps of endospore staining?
1. Primary stain: malachite green, usually with heat; 2. Decolorize cells: water; 3. Counterstain: safranin
159
How do spores appear in endospore staining?
Green within red or pink cells
160
What are resistant, dormant structures inside some cells that cannot be stained by ordinary methods?
Endospores
161
Is decolorizing cells with water the first step in endospore staining?
No
162
Is counterstaining with safranin the third step in endospore staining?
Yes
163
Is primary staining with malachite green and heat the first step in endospore staining?
Yes
164
Is counterstaining with malachite green the third step in endospore staining?
No
165
Is decolorizing cells with water the second step in endospore staining?
Yes
166
Is primary staining with safranin the first step in endospore staining?
No
167
What are flagella?
Structures of locomotion
168
How does flagella staining work?
By using a mordant and carbolfuchsin to thicken appearance of flagella and make them visible under light microscope
169
These are structures of locomotion
Flagella
170
Does flagella staining use mordant?
Yes
171
Mordant and carbolfuchsin are used in what type of staining?
Flagella staining
172
This type of staining uses mordant and carbolfuchsin to thicken flagella appearance and make them visible under light microscopes
Flagella staining
