Chapter 3 Flashcards Preview

Microbiology > Chapter 3 > Flashcards

Flashcards in Chapter 3 Deck (57):
0

Measure of how greatly a substance slows the velocity of light

Measure of the light bending ability of a medium

Refractive index

1

Direction and magnitude of bending Is determined by the refractive indexes of the two media forming the interfaces

Bending of light

2

Ability of a lens to separate or distinguish small objects that are close together

Resolving power

3

Wavelength of light/ 2x nunerical aperture

Resolving power

4

Function of the diameter of the objective lens to its focal length

Numerical aperture

5

Bright field microscope
Dark field microscope
Phase contrast microscope
Fluorescence microscope

Light microscope

6

Produces dark image against brighter background
Has several objective lenses

Bright Field microscope

7

Used to study living microorganisms
Contains opaque disc that will block light from directly entering the objective lens. Only light reflected from specimen enters the objective lens

Darkfield microscopy

8

No staining/Study living microbes
Image appear dark against light background. Has special objectives and a condenser that make cellular component visible which differ only slightly in their refractive indexes

Phase contrast microscopy

9

Ability of substances to absorb short wavelength of light (UV) and give of longer wavelength light (visible)

Fluorescence

10

Fluorescence dyes
An be chemically combined with an antibody, complex used in diagnosis to check the presence of an antigen(microbe)

Fluorochromes

11

Uses ultra violet or near ultraviolet wavelength light source
Organisms with fluorchrome appear luminescent against dark background

Fluorescence microscope

12

Transmission electron microscope (TEM)

Scanning electron microscope (SEM)

Electron microscope

13

Examine objects smaller than 0.2 um like viruses and internal cellular structures
Electrons used
Images are black & white
Electromagnetic lenses instead of glass lenses

Electron microscopy

14

Electrons scatter when they pass thirty ultra thin sections of a specimen
Transmitted electrons are used to produce image
Objects 10,000-100,000
Internal structures
Resolution 2.5nm

Transmission electron microscope

15

Uses electrons reflected from surface of a specimen to create 3D image
No sectioning
Objects magnified 1,000-10,000x
External images

Scanning electron microscope.

16

Bacterial smear is a fries preparation of bacterial cells on a glass slide
Require only small amount of the microbial culture

Smear

17

Done by passing the air dried smear several times over the flame or using blow dryer
Smear is fixed
Coagulates bacterial protein so bacteria stick to the slide surface

Heat fixation

18

Done to study the microbial properties and to group the microbes in specific groups for diagnosis

Staining

19

Coloring microbes with dye that creates contrast between bacteria and background and emphasis microbial structures

Staining

20

Organic compound contains benzene ring plus a chromosphere and auxochrome group

Stain

21

Salts composed of a positive and negative ion, one of which is colored and is non as the chromophore

Stains

22

Contains positive ions
Crystal violet
Methylene blue
Malachite green
Safranin

Basic dye

23

Contains negative ions
Eosin
Acid fuchsin
Nigrosin

Acidic dye

24

Used to observe the overall shape size and capsules
No heat fixation required

Negative staining

25

Simple
Differential
Special

Kinds of staining

26

Aqueous or alcohol solution of single basic dye
Creates contrast between Bactria and background
Highlights entire microorganism to study cell shape, size, arrangement
Heat fixed

Simple staining

27

Methylene blue
Crystal violent
Carbolfuchsin
Safranin
Mordant** (sometimes)

Simple staining

28

Requires the use of at least three chemical reagents that are applied sequentially to a heat fixed smear
1. Primary stain
2. Decolorizing agent
3. Counterstain

Differential staining

29

Imparts it's color to all cell

Primary stain

30

Bases on chemical composition of cellular components.

Decolorizing agent

31

Contrasting color to that of the primary stain

Counterstain

32

Differential staining procedure developed by Hans Christian Gram in 1884

Gram staining

33

Primary stain crystal violet (basic purple dye) applied to heat stain

Gram staining step 1

34

After washing primary stain iodine (mordant) is applied that will make crystal violent complex
Bacteria at this point appear dark violet or purple

Gram staining step 2

35

Alcohol, alcohol acetone solution applied as decoloring agent and removes purple color from Gram negative bacteria
** Gram Positive will retain purple color

Gram Staining step 3

36

Alcohol rinsed and the slide is then stained with Counterstain Safranin(basic red dye)

Gram Staining step 4

37

Have thicker layer if Peptidoglycan in cell wall. CV-1 complex is not washed by alcohol wash. They retain the CV-1 complex and remain purple

Gram positive bacteria

38

Have thinner layer of Peptidoglycan and also have layer of lipopolysachharide as part of their cell wall.
Alcohol disrupts layer and CV-1 complex is washed through
***will remain colorless unless counter stain Safranin applied, become pink

Gram negative

39

Penicillins
Cephalosporins

*cannot penetrate lipopolysachharide layer of gram negative**

Beta Lactams

40

Uses to distinguish Myobacterium species and some species of Nocardia
Bind strongly to waxy material of the cell wall

Acid fast staining

41

Carbol fushion(red dye) applied to fixed smear








Acid fast staining step 1

42

After cooling & washing smear washed with alcohol decolorizer
*Non acid fast lose stain
**Acid fast retain dye, more soluble in lipid cell wall than in acid alcohol

Acid fast staining step 2

43

Counter stain methylene blue is used to stain non acid fast bacteria blue

Acid fast staining step 3

44

Schaeffer-Fulton stain
1. Heat fixed smear
2. Primary stain Malachite green applied, heated (stain wall)
3. Washed to remove excess
4. Counter stain Safranin applied to stain other parts pink

Endospore special stains

45

Determines microbes virulence
Gelatinous covering that is soluble in water.
India Ink or Nigrosin stains background dark
Safranin used to stain cells
Capsules look like Halos around stained cells

Capsule staining

46

Mordant used to build diameter
When stained with Carbolfuchsin becomes visible under light microscope.
Number and location used in diagnosis

Flagella Staining

47

4x

Scanning

48

10x

Low power

49

40-45x

High power

50

90-100x

Oil immersion

51

Ocular lens

10x

52

Ocular lens x objective lens

Total magnification

53

Any kind of microscope that uses visible light to observe specimen

Are compound microscope

Light microscope

54

Microscope remains in focus even objectives are changed

Parfocal

55

Acid fast color

Red

56

Non acid fast color

Blue