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1
Q

Light microscopes are considered…. since they have two lenses

A

Compound microscopes

2
Q

Types of compound microscopes

A

Bright-field

dark field

3
Q

Lenses that work together to magnify objects

A

Objective and ocular

4
Q

Objectives are composed of several lens elements that magnify the object first called the …. which produces….

A

Primary magnification - real image

5
Q

the —- is composed of several lens elements that magnify the real image, called the

A

Ocular … Secondary magnification

6
Q

The secondary magnification produces as —– which is seen at —-

A

Virtual image —- eye point

7
Q

Total Magnification

A

Product of the objective and ocular lens

8
Q

Resolving power

A

Resolution - limits useful magnification for compound microscopes

9
Q

Stage

A

Where the specimen is placed

10
Q

Two adjustment knobs

A

Course - primary focusing

Fine - secondary focusing

11
Q

Parfocality

A

Ability to move from one objective to another while using only fine adjustment knob

12
Q

Working distance

A

Distance b/w specimen on the slide and objective lens when in focus

13
Q

As magnification increases

A

The field of view decreases

14
Q

As magnification increases,

A

More light is needed.

15
Q

Why is light conserved in oil?

A

Glass and oil have same refractive indexes

16
Q

Absorption

A

Light passes through specimen

17
Q

Refracted

A

Light is reflected off specimen

18
Q

Phasecontrast

A

Differentiates between specimens of different densities

19
Q

Fluorescent

A

Koon’s fluorescent antibody technique

20
Q

Resolving power

A

Minimum distance that can exist between two object and still allow the two objects to be seen as separate

21
Q

Magnification - resolution relationship

A

As you increase magnification, resolution increases until about 1000x, at which time there is an inverse relationship between the two

22
Q

Light is the portion of the spectrum of electromagnetic waves that is visible to the human eye and are between

A

400-700nm

23
Q

Bright field microscopy technique normally used for

A

Study of live or preserved/stained material. Common multipurpose scope

24
Q

Dark field microscope is equipped with ______ condenser and an objective with _______ aperture.

A

Dark-field

Low numerical

25
Q

Result of a dark field microscope when viewing:

A

Only peripheral light reflected off the sides of the specimen enter the objective

26
Q

Dark field microscopy is best to view

A

Living, unstained orgs

Examples: syphilis studies because it provides a specimen outline with reduced internal cellular details

27
Q

Fluorescence microscope

A

Microscope is furnished with an ultraviolet radiation source and a filter that protects the eyes

28
Q

Def; Fluorescence

A

Ability to absorb short wavelengths of light and give off light at a longer wavelength that can be seen with use of special filters

29
Q

Explain prep for fluorescent scope use

A

Specimen is first coated with or placed in contact with fluorescent molecule. Stained with fl. Dyes or combined wit fl. Antibodies; illumination by UV radiation causes light to be given off, forming an image

30
Q

Wide use of fl. Microscopy

A

Diagnosis of infections caused by certain bacteria, protozoa, fungi and viruses

31
Q

Phase contract microscope

A

Equipped with a special condenser contains and annular ring shaped diaphragm.

32
Q

Diaphragm function on phase contract scope

A

Allows direct light to pass through condenser focusing light on specimen and a refraction plate in the objective lens. Direct and reflected or diffracted light rays are brought together in phase to form the image of the specimen.

33
Q

Application of phase contrast

A

Locating structures within live, unstained cells that are not seen under other scopes

34
Q

Electron microscopes are

A

Use electron beams instead of life; all aspects controlled by electromagnets instead of glass. Have greater resolving power b/c of short wavelengths of the electron beams

35
Q

TEM use

A

Beam of electrons passed through 20-100nm sections of specimen. Seen on a screen. Contrast can be increased by staining or soaking specimen in metals.

Used to eye detailed structures on preserved material (dead).

36
Q

TEM reveals

A

Ultrastructure of cells

37
Q

SEM

A

Produces three dimensional image of specimen, offering surface detais

38
Q

How SEM works

A

Electron beams scan back and forth over intact, metal coated specimen from the top

Electrons leaving surface of the specimen picked up by detector

Electron patter displayed as image on television screen or photographic film

39
Q

Resolving power (resolution)

A

The ability of lenses to distinguish between two points a specified distance apart

40
Q

Types of preparations for light microscopic examinations

A

Wet mount/hanging drops: suspension in liquid

Dried, fixed, and stained smears

41
Q

Wet mount and hanging drop techniques…

What is the quality of the resolution?

A

Wet mount: place liquid suspension of org on a slide and cover with a slip

Drop: suspension place on cover slip, positioned over a well on depression slide

Poorer than in dyed preparation

42
Q

Staining techniques offer

A

Greater resolution because of color contrast

43
Q

Positive stains use _____ dyes which stain _______

A

Basic

Cells or cell parts

44
Q

Simple stains

A

Positive stain

One dye used to see morphology and cell arrangement

45
Q

Differential stains

A

Positive stain

Use more than one reagent to see differentiation between cells and cell parts

46
Q

Gram stain

A

Differential stain

Groups gram - and gram + cells

47
Q

Acid Fast stain

A

Positive stain

Bacteria that cause tuberculosis and hansen’s disease are acid fast; most others are not

48
Q

Giemsa stain

A

Positive stain

Used to detect parasites in blood

49
Q

Endospore stain

A

Positive stain

Detects presence of endospores

50
Q

Capsule stain and Flagella stain

A

Positive stains

51
Q

Negative stain

A

Use acidic dyes that stain background around cells and leave cells colorless; can see shape and arrangement better

52
Q

Stains have ______ significance

A

Practical diagnostic

53
Q

Streak plate method

A

Inoculum spread over solid culture with loop

54
Q

Spread plate method

A

Inoculum spread over surface of a solid medium with spreader

55
Q

Pour plate method

A

Inoculum mixed in melted agar medium and poured into sterile petri dish

56
Q

Enrichment culture

A

Culture medium used for preliminary isolation that favors the growth of a particular microorganism (blood agar, glucose, etc)

57
Q

Stock cultures

A

Preserved for study and reference

58
Q

Stock culture preservation

A

Short - refrigeration at 0-10 celsius

Long - liquid nitrogen at -196 celsius or lyophilization

59
Q

Culture (def)

A

Observable growth in or on a culture medium

60
Q

Inoculation

A

Introduction of a tiny sample of cells into medium that encourages growth

61
Q

Only dead specimens can be viewed with

A

Electron microscope

62
Q

Light microscopes have ….. lenses instead of electromagnetic beams

A

Glass lenses

63
Q

TEM magnification

A

500,000X

64
Q

SEM magnification

A

200,000-250,000x

65
Q

1000-2000x

A

Light microscopes

66
Q

Light microscope resolving power

A

0.2-0.3um

67
Q

TEM resolving power

A

0.0001um

68
Q

SEM resolving power

A

0.02um

69
Q

Ultrastructure

A

Sub microscopic structure

70
Q

Resolving power of light

A

Wavelength of light / 2x Numerical Aperture