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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