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Microbiology Chapters flashcards > Microbiology CH. 3 Observing Microorganisms > Flashcards

Microbiology CH. 3 Observing Microorganisms Flashcards

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Biology 101 flashcards
1
Q

Microorganism

A

too small to be seen with unaided eye

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2
Q

microscope

A

derived from “micro” — small
greek word “skopos”: to look at it

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3
Q

antoni van Leeuwenhoek

A

invented microscope

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4
Q

when was the first clear mention of microorganisms and their discovery

A

1676

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5
Q

describe Leeuwenhoek microscope

A

self-made
hand-held
single lens
magnified 100X
drawings indicative of species are still known to be present in materials he examined

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6
Q

3 types of microscopes

A

light; electron; scanned probe (diamond/metals)

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7
Q

what does light microscopy refer to ?

A

any microscope that uses visible light

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8
Q

what are the several types of light microscopy

A

compound light
darkfield
phase-contrast
differential interface contrast (DIC)
Fluoresce
confocal

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9
Q

how do you find out the total magnification of a compound light microscope

A

total magnification is calculated by multiplying the magnification of objective lens by the magnification of ocular lens

ex. objective lens 40x
ocular lens 10x
40x10=400x

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10
Q

what are some components used with the compound light microscope

A

resolution, refractive index, and immersion oil

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11
Q

resolution def?

A

resolving power —- lenses ability to distinguish fine details of structure

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12
Q

refractive index ?

A

measure of light-bending ability of a medium

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13
Q

immersion oil def?

A

reduce light loss between slide and the lenses

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14
Q

darkfield microscopy

A

uses special condenser with opaque discs that block light from entering objective lens directly

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15
Q

what does darkfield microscopy show

A

light silhouette of organism against dark background

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16
Q

what is darkfield microscopy most useful for

A

it is most useful for detecting presence of extremely small organisms

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17
Q

what does darkfield microscopy examine

A

unstained microorganisms suspended in media
ex. paramecium

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18
Q

what is phase-contrast microscopy

A

brings direct reflected/diffracted light rays together (in phase) to form image of specimen on ocular lens

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19
Q

what does phase-contrast microscopy allow

A

detailed observation of living organisms internal structures

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20
Q

what does phase-contrast microscopy not require

A

staining

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21
Q

how does differential interface contrast microscopy (DIC) work

A

uses 2 beams of light separated by a prism

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22
Q

what kind of image does DIC microscopy provide

A

a colored 3 dimensional image of object being observed

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23
Q

what does DIC microscopy allow

A

detailed observations of living cells

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24
Q

what does DIC microscopy not require

A

staining

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25
Q

what is Fluorescence Microscopy FM

A

specimens are stained with fluorochromes and viewed through compound microscope using ultraviolet light source

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26
Q

how do microorganisms appear on FM microscope

A

bright objects against a dark background
ex. T. pallidum

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27
Q

what is FM microscopy primarily used in

A

diagnostic procedure called fluorescent-antibody (FAb) technique
or
immunofluorescence to detect and identify microbes in tissues or clinical specimens

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28
Q

what is confocal microscopy

A

uses laser light to illuminate one plane of specimen at a time

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29
Q

what type of image is produced in confocal microscopy

A

2 and 3 dimensional images of cells for biomedical applications

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30
Q

what is electron microscopy EM

A

uses beam of electrons instead of light

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31
Q

what is used instead of glass in EM microscopy to focus, illuminate, and magnify

A

electromagnets

32
Q

what processes in EM microscopy does electromagnets use to control focus, illuminate, and magnify

A

transmission/scanning EM

33
Q

what does Transmission EM examine

A

viruses or internal ultra structure in thin sections of cells

34
Q

how does transmission EM work

A

electrons pass through the specimen

35
Q

what is the magnification range on transmission EM

A

10,000X - 100,000X

36
Q

what type of image is produced in transmission EM

A

2-dimensional image

37
Q

what is scanning EM

A

e-beam (electron beam) is directed at intact specimen from the top rather than passing through sections

electrons leaving the surface of specimen (2ry e-) are viewed on television like screen

38
Q

what is scanning EM used to study

A

surface features of cells and viruses

39
Q

what is the range of magnification of Scanning EM

A

1000x-10,000x

40
Q

what are the 2 processes used in scanned-probe microscopy

A

scanning tunneling and atomic force

41
Q

what is scanning tunneling in scanned-probe microscopy

A

uses thin metal probe that scans specimen and produces an image revealing bumps and depressions of the atomic on the surface of the specimen

42
Q

what is atomic force in scanned-probe microscopy

A

uses a metal and diamond probe gently forced down along the surface of the specimen

43
Q

what type of image does atomic force in scanned probe microscopy produce

A

3-dimensinal image

44
Q

what are the 3 different staining techniques

A

simple, differential, and special

45
Q

what are stains

A

salts composed of a positive (NA+) and a negative ion (Cl-)
sodium chloride

46
Q

Chromophore

A

part of molecule responsible for stain color
bacteria (neg charged) and pos ion of chromophore (basic dye ) will stain it

47
Q

What the common basic dyes with positive charges

A

crystal violet
methylene blue
safranin
malachite green

48
Q

what are the common acidic dyes with negative charges

A

eosin
carbolfuchsin
nigrosin

49
Q

what are simple stains

A

aqueous or alcohol solution of basic dyes methylene blue, crystal violet, and safranin

50
Q

what is the purpose of simple staining

A

visualize shapes and arrangements of cells

51
Q

what is mordant used for

A

improve bonding between the stain and the specimen

52
Q

what are differential stains

A

react differently with types of bacteria

53
Q

what are the 2 most common differential stains

A

gram stain and acid-fast stain

54
Q

when was gram stain used and who invented it

A

in 1884 by Hans Christian Gram

55
Q

what is the most important stain used in bacteriology

A

gram stain

56
Q

what does gram stain do?

A

divides bacteria into 2 groups
Gram (+) and Gram(-)

57
Q

how does gram stain and acid fast stain differentiate bacteria

A

differentiate according to bacteria reactions to the stain

58
Q

what does gram stain procedure use

A

purple stain (crystal violet)
iodine (mordant)
alcohol decolorizer
red counterstain(safranin)

59
Q

what is the application process of gram stain

A

application of crystal violet (purple dye)
application of iodine(mordant)
alcohol wash (decolorizer) 95% alcohol or acetone
application of safranin (counterstain)

60
Q

what does application of safranin (counterstain) provide in gram stain

A

provides contrast to the 1ry stain

61
Q

what is the gram stain mechanism

A

crystal violet-iodine crystals form in cell

62
Q

gram positive def?

A

alcohol dehydrates peptidoglycan
CV- 1 crystals do not leave

63
Q

gram negative def?

A

alcohol dissolves outer membrane and leaves holes in peptidoglycan
CV-1 ashes out

64
Q

What do the results look like in gram stain

A

Gram (+) purple
Gram (-) red

65
Q

what determines the difference of bacteria in gram stain

A

structure of cell wall
gram(+) thick cell wall
gram (-) thin cell wall

66
Q

what are acid-fast microbes members of

A

genera

67
Q

what does mycobacterium and nocardia do in acid-fast stain

A

retain carbolfuchsin after acid alcohol decolorization and appear red

68
Q

non-acid fast microbes take up which counterstain and appear what color

A

take up methylene blue counterstain and appear blue

69
Q

what are special stains used for

A

used to color and isolate specific parts of microorganisms

70
Q

which microorganisms are special stains used to color and isolate

A

endospores
flagella
capsules

71
Q

what is the process of negative staining for capsules

A

microbiologist mix bacteria in solution containing fine colloidal suspension of colored particles (india ink or nigrosin )
and then stained with simple stains of safranin

72
Q

what do capsules not accept and how do they appear

A

don’t accept most stains and appear as unstained halos around bacterial cells and stand out against a dark background
ex. K pneumoniae

73
Q

what is the process of endospore staining(specials staining)

A

Schaeffer Fulton endospore stain uses malachite green (1ry stain)
heat/wash
add safranin (counterstain) to stain portions of the cells other than endospores
ex. bacillus cereus

74
Q

what is the process of flagella staining (special staining )

A

used a mordant and the stain carbolfuchsin to build up the diameters of flagella until they become visible under the light microscope
the mordant intensifies the stain or wats a structure to make it thicker and easier to see after it is stained
ex. salmonella typhosa

75
Q

what can a mordant do for flagella

A

because flagella can’t be normally seen the mordant can be used to increase the diameter of the flagella before it is stained

Microbiology Chapters flashcards (7 decks)

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