Micro Midterm #1 Chapter 3

Front 1

1 µm = ? m = ? mm

Back 1

10-6 m = 10-3 mm

Front 2

1 nm = ? m = ? mm

Back 2

10-9 m = 10-6 mm

Front 3

1000 nm = ? µm

Back 3

1000 nm = 1 µm

Front 4

0.001 µm = ? nm

Back 4

0.001 µm = 1 nm

Front 5

Explain the importance of oil when using the oil immerion objective.

Back 5

Oil reduces light loss between slide and the lens. Used to keep light from bending.

Front 6

Identify a use for Dark field when the Bright field illumination is not sufficient.

Back 6

Dark objects are visible against a bright background. Shows a light silhouette of an organism against a dark background. It is most useful for detecting the presence of extremely small organisms.

Front 7

Identify a use for Phase Contrast when the Bright field illumination is not sufficient.

Back 7

Accentuates diffraction of the light that passes through a specimen. Brings direct and reflected or diffracted light rays together (in phase) to form an image of the specimen on the ocular lens. Allows the detailed observation of living organisms.

Front 8

Identify a use for DIC when the Bright field illumination is not sufficient.

Back 8

Accentuates diffraction of the light that passes through a specimen; uses two beams of light.
-Provides a colored, three-dimensional image of hte object being observed. Allows detailed observations of livng cells.

Front 9

Identify a use for Florescence when the Bright field illumination is not sufficient.

Back 9

-Uses UV light.
-Fluorescent substances absorb UV light and emit visible light.
-Cells may be stained with fluorescent dyes (fluorochromes).
Specimens are first stained with fluorochromes and then viewed through a compound microscope by using an ultraviolet light source. Microorganisms appear as bright objects against a dark background. Used primarily in a diagnostic procedure called fluorescent-antibody (FA) technique, or immunofluorescence.
-absorb UV light and emit visible light

Front 10

Identify a use for Transmission Electron Microscop (TEM), when the Bright filed illumination (the one we use) is not sufficient

Back 10

-Ultrathin sections of specimens.
-Light passes through specimen, then an electromagnetic lens, to a screen or film.
-Specimens may be stained with heavy metal salts.
-10,000-100,000; resolution 2.5 nm

Front 11

Identify a use for Scanning Electron Microscop (SEM), when the Bright filed illumination (the one we use) is not sufficient

Back 11

-An electron gun produces a beam of electrons that scans the surface of a whole specimen.
-Secondary electrons emitted from the specimen produce the image.
-Three-dimensional views of the surfaces of whole microorganisms can be obtained. Magnification: 1000–10,000×. Resolving power: 20 nm.

Front 12

-Uses electrons instead of light.
-The shorter wavelength of electrons gives greater resolution.

Back 12

Electron Microscopy

Front 13

PEQ Explain how electron microscopic methods (TEM & SEM) differ from light microscopy

Back 13

-TEM differs from light in that it uses electrons instead. The shorter wave lengths of electrons gives greater resolution.
-differ from Light Microscopes
Uses a beam of electrons, instead of light. Electromagnets, instead of glass lenses, control focus, illumination, and magnification. Thin sections of organisms can be seen. Magnification: 10,000–100,000×. Resolving power: 2.5 nm.

Front 14

coloring a microorganism with dye to make some structures more visible

Back 14

stain

Front 15

-use of single basic dye
-A mordant may be used to hold the stain or coat the specimen to enlarge it.
-An aqueous or alcohol solution of a single basic dye, used to make cellular shapes and arrangements visible. A mordant may be used to improve bonding between the stain and the specimen.

Back 15

simple stain

Front 16

-The Gram stain classifies bacteria into gram-positive and gram-negative.
-Gram-positive bacteria tend to be killed by penicillin and detergents.
-Gram-negative bacteria are more resistant to antibiotics. Decolorizer make gram negatives colorless. Safranin makes gram negative red.

-Gram stain and acid-fast stain, differentiate bacteria according to their reactions to the stains. Gram stain procedure uses a purple stain (crystal violet), iodine as a mordant, an alcohol decolorizer, and a red counterstain. Gram-positive bacteria retain the purple stain after the decolorization step; gram-negative bacteria do not and thus appear pink from the counterstain.
-Acid-fast microbes, such as members of the genera Mycobacterium and Nocardia, retain carbolfuchsin after acid-alcohol decolorization and appear red; non–acid-fast microbes take up the methylene blue counterstain and appear blue.

Back 16

differential stain

Front 17

-negative, heat, and flagella
-Capsule staining provides a contrasting background, so the capsules of these bacteria show up as light areas surrounding the stained cells.

Back 17

special stain

Front 18

procedure classifies bacteria into two large groups: gram-positive and gram-negative.

Back 18

Gram stain

Front 19

Reagents in gram stain

Back 19

•Primary stain: crystal violet
•Mordant: iodine
•Decolorizing agent:
-alcohol-acetone
•Counterstain: safranin

Front 20

PEQ Describe the order and names of the reagents in the Gram Stain, and be able to explain what is happening to differentiate the cells at each step.

Back 20

1. A heat-fixed smear is covered with a basic purple dye, usually crystal violet. Because the purple stain imparts its color to all cells, it is referred to as a primary stain.
2. After a short time, the purple dye is washed off, and the smear is covered with iodine, a mordant. When the iodine is washed off, both gram-positive and gram-negative bacteria appear dark violet or purple.
3. Next, the slide is washed with alcohol or an alcohol-acetone solution. This solution is a decolorizing agent, which removes the purple from the cells of some species but not from others.
4. The alcohol is rinsed off, and the slide is then stained with safranin, a basic red dye. The smear is washed again, blotted dry, and examined microscopically.

Front 21

PEQ Describe the order and names of the reagents in the Gram Stain, and be able to explain what is happening to differentiate the cells at each step.

Back 21

Front 22

Understand the mechanism of these stains and give an example of something we might be looking for with each: Acid Fast, Endospore, Capsule Stains

Back 22

-Acid fast: binds strongly only to bacteria that have a waxy material. We look for tuberculosis and leprosy microbes. Reddish color
-Endospore: special resistant structure that protects bacterium. Appear green
-Capsule stains: determines the organism’s virulence.
Stained with colored particles then with a simple stain.

Front 23

In the this staining procedure, the red dye carbolfuchsin is applied to a fixed smear, and the slide is gently heated for several minutes. (Heating enhances penetration and retention of the dye.) Then the slide is cooled and washed with water. The smear is next treated with acid- alcohol, a decolorizer, which removes the red stain from bacteria that are not acid-fast. The acid-fast microorganisms retain the red color because the carbolfuchsin is more soluble in the cell wall lipids than in the acid-alcohol One that differentiates bacteria into distinctive groups which binds strongly only to bacteria that have a waxy material in their cell walls. Microbiologists use this stain to identify all bacteria in the genus Mycobacterium, including the two important pathogens Mycobacterium tuberculosis, the causative agent of tuberculosis, and Mycobacterium leprae (lep′rī), the causative agent of leprosy

Back 23

Acid Fast

Front 24

Malachite green, the primary stain, is applied to a heat-fixed smear and heated to steaming for about 5 minutes. The heat helps the stain penetrate the _____ wall. Then the preparation is washed for about 30 seconds with water to remove the malachite green from all of the cells’ parts except the ______(s). Next, safranin, a counterstain, is applied to the smear to stain portions of the cell other than ________(s). In a properly prepared smear, the __________(s) appear green within red or pink cells. Because ________(s) are highly refractive, they can be detected under the light microscope when unstained, but they cannot be differentiated from inclusions of stored material without a special stain.

Back 24

Endospore

Front 25

Many microorganisms contain a gelatinous covering called a _______. In medical microbiology, demonstrating the presence of a _______ is a means of determining the organism’s virulence, the degree to which a pathogen can cause disease. It provides a contrasting background, so the _______(s) of these bacteria, Klebsiella pneumoniae, show up as light areas surrounding the stained cells.

Back 25

Capsule Stains

Front 26

standard unit of length

Back 26

meter

Front 27

1/100 m

Back 27

centimeter

Front 28

1/1000 m

Back 28

millimeter

Front 29

1/1,000,000 m

Back 29

micrometer

Front 30

1/1,000,000,000 m

Back 30

nanometer

Front 31

length of waves; light, gamma, radio

Back 31

wavelength

Front 32

centi c 10-2 = 0.01
Milli m 10-3 = 0.001
micro µ 10-6 = 0.000,001
nano n 10-9 = 0.000,000,001

Back 32

centi c 10-2 = 0.01
Milli m 10-3 = 0.001
micro µ 10-6 = 0.000,001
nano n 10-9 = 0.000,000,001

Front 33

the ability of the lenses to distinguish two points a specified distance apart.

(also called resolving power) is the ability of the lenses to distinguish fine detail and structure ~ distinguish between two points a specified distance apart.

Back 33

resolution

Front 34

the same as resolution

Back 34

resovling power

Front 35

a constant based on the quality of the lens, the higher the numerical aperture the better the resolution

Back 35

numerical aperture

Front 36

the change in direction of a wavefront at an interface between

Back 36

reflection

Front 37

the bending of light when it passes from one medium to another; i.e. air to water.

Back 37

refraction

Front 38

transmitting waves or something.

Back 38

transmission

Front 39

the ability to absorb

Back 39

absorption

Front 40

to zoom in at an image

Back 40

magnification

Front 41

the bending or spreading of a beam of light when passing through a narrow opening

is the scattering of light rays as they “touch” a specimen’s edge. The diffracted rays are bent away from the parallel light rays that pass farther from the specimen. When the two sets of light rays– direct rays and reflected or diffracted rays–are brought together, they form an image of the specimen on the ocular lens, containing areas that are relatively light (in phase), through shades of gray, to black.

Back 41

diffraction

Front 42

the positive ion, the chromophore is a cation

A salt in which the color is in the positive ion; used for bacterial stains.

Back 42

basic dyes

Front 43

the negative ion, the chromophore is an anion

A salt in which the color is in the negative ion; used for negative staining.

Back 43

acidic dyes

Front 44

aqueous or alcohol solution of a single basic dye

A method of staining microorganisms with a single basic dye. Used to make cellular shapes and arrangements visible. A mordant may be used to improve bonding between the stain and the specimen

Back 44

simple staining

Front 45

react with different kind of bacteria and can be used to distinguish them.

A stain that distinguishes objects on the basis of reactions to the staining procedure.

Back 45

differential staining

Front 46

-Staining the background instead of the cell
-preparing colorless bacteria against a colored background
-A procedure that results in colorless bacteria against a stained background..

Back 46

negative staining

Front 47

uses fluorochromes and a laser light.

Back 47

confocal microscopy

Front 48

lens that stays in focus when the magnification is changed.

Back 48

parfocal

Front 49

the electrons pass through a thin section of the specimen

Back 49

transmission electron microscope

Front 50

visible light passes throught he specimen; uses separate objective and ocular lenses

Back 50

compound light microscope

Front 51

Details become visible because of differences in the refractive index of different parts of the cell

Back 51

Phase-contrast microscope

Front 52

visible light is scattered after striking the specimen, and the specimen is visible agains a darkened background

Back 52

darkfield microscope

Front 53

a special microscope using ultraviolet illumination

Back 53

fluorescence microscope

Front 54

the electrons strike the surface of the speciment, and secondary electrons leaving the surface are veiwed on a television-like screen

Back 54

scanning electron microscope

Front 55

makes use of relatively low-energy red light to excite fluorochromes; can track cellular activity in real tiem

Back 55

two-photon microscopy

Front 56

pertaning to the relative velocities of light through a substance

Back 56

refractive index

Front 57

involves the use of antibodies and ultraviolet light

Back 57

immunofluorescence

Front 58

one-millionth of a meter

Back 58

resloving power

Front 59

one ten-billionth of a meter

Back 59

angstrom

Front 60

the ability to sparate two points in a microscopy filed

Back 60

reslvoing power

Front 61

Adhere(s) best to bacteria, which have a negative charge, because the color molecule has a positive charge

Back 61

basic dyes

Front 62

used in diagnosis of tuberculosis

Back 62

acid-fast stain

Front 63

involves(s) the use of a negative stain made from India ink particles

Back 63

capsule stain

Front 64

schaeffer-fulton stain

Back 64

endospore stain

Front 65

uses carbolfuchsin dye

Back 65

acid-fast stain

Front 66

uses malachite green

Back 66

endospore stain

Front 67

relfect(s) a bsic difference between microbial cell walls: ethanol will not remove stain from bacteria

Back 67

gram stain

Front 68

a microscope that uses laser illumination

Back 68

confocal

Front 69

extremely thin microbes, for example the spirochete

Back 69

darkfield

Front 70

this type of electron microscope yields images with seemingly three-dimensional view of the specimen

Back 70

scanning

Front 71

light rays that pass through different portions of the specimen reach the eye with their wave peaks reinforced or cancelled, making structures of the specimen relatively light or dark

Back 71

phase-contrast

Front 72

a microscope that uses sound waves to form an image

Back 72

scanning acoustic

Front 73

formerly known as a micron

Back 73

micrometer

Front 74

formerly known as a millimicron

Back 74

nanometer

Front 75

this is 10 -10 of a meter

Back 75

angstrom

Front 76

a billionth of a meter

Back 76

nanometer

Front 77

did not do fill in the blanks

Back 77

did not do fill in the blanks

Front 78

used to distinguish mycobacterium species and some species of Nocardia. Once, stained with carbolfuchsin and treated with acid-alcohol, remain red because they retain the carbolfuchsin stain. Non-acid-fast bacteria, when stained and treated the same way and then stained with methylene blue, appear blue because they lose the carbolfuchsin stain and are then able to accept the methylene blue stain.

Back 78

acid-fast

Front 79

used to demonstrate the presence of capsules. Because capsules do not accept most stains the capsules appear as unstained halos around bacterial cells and stand out against a constrasting background

Back 79

negative

Front 80

used to detect the presence of endospores in bacteria. When malachite green is applied to a heat-fixed smear of bacterial cells, the stain penetrates the endospores and staines them green. When safranin (red) is then applied, it stains the remainder of the cells red or pink.

Back 80

endospore

Front 81

Tuberculoses

Back 81

acid-fast

Front 82

Be able to explain the importance of ioil when using the oil immersion objective

Back 82

Immersion oil is used with the oil immersion lens to reduce light loss between the slide and the lens

Front 83

capsule

Back 83

Klebsiella pnemoniae

Front 84

endospore

Back 84

tetnus

Front 85

the most common microscope used in microbiology is the

Back 85

compound light microscope

Front 86

the total magnification of an object is calculated by multiplying the magnification of the objective lens by the magnification of the ocular lens.

Back 86

compound light microscopy

Front 87

uses visible light

Back 87

compound light microscope

Front 88

the maximum resolution, or resolving power (the ability to distinguish two points) is 0.2 um; maximum magnification 2000x

Back 88

compound light microscopy

Front 89

brightfiled illumination is used for stained smears

Back 89

compound light microscopy

Front 90

unstained cells are more productively observed using darkfield, pahse-contrast, or DIC microscopy

Back 90

compound light microscopy

Front 91

shows a light silhouette of an organism against a dark background

Back 91

darkfield microscope

Front 92

it is most useful for detecting the presence of extremely small organisms

Back 92

darkfiled microscope

Front 93

birngs direct and reflected or diffracted ligth rays togehter (in phase) to form an image of the specimen on the ocular lens

Back 93

phase-contrast microscopy

Front 94

it allows the detailed observation of living organisms

Back 94

Phase-contrast microscopy

Front 95

provides a colored, three-dimensional image of the object being observed.

Back 95

Differential Interference Contrast (DIC)

Front 96

It allows detailed observations of living cells

Back 96

Differential Interference contrast (DIC)

Front 97

specimens are first stained with fluorochromes and then viewed through a compound microscope by using an ultraviolet light source

Back 97

fluorescence microscopy

Front 98

The microorganisms appear as bright objects against a dark background

Back 98

fluorescence microscopy

Front 99

used primarily in a diagnostic procedure called fluorescent-antibody (FA) technique, or immunofluorescence.

Back 99

fluorescence microscopy

Front 100

is an aqueous or alcohol solution of a single basic dye

Back 100

simple stain

Front 101

it is used to make cellular shapes and arrangments visible

Back 101

simple stain

Front 102

a mordant may be used to improve bonding between the stain and the specimen

Back 102

simple stains

Front 103

differentiate bactyeria according to their reactions to the stains; such as Gram stain and acid-fast stain

Back 103

differential stains

Front 104

The Gram stain proceudre uses a purple stain (crystal violet) iodine as a mordant, an alcohol decolorizer, and a red counterstain

Back 104

differential stains

Front 105

Gram-positive bacteria retaint he purple stain after the decoloriation step; gram-negative bacteria do not and thus appear pink from the counterstain

Back 105

differential stains

Front 106

acid-fast microbes, such as members of the genera Mycobacterium and Nocardia, retain carbolfuchsin after acid-alcohol decolorization and appear red; non acid -fast microbes take up the methylene blue counterstain and appear blue.

Back 106

differential stains

Front 107

negative staining is used to make microbial capsules visible

Back 107

special stains

Front 108

the endospore stain and flagella stain are special stains that color only certain parts of bacteria

Back 108

special stains