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Microbiology 210 > Methods > Flashcards

Flashcards in Methods Deck (70)
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1

Light microscopes are considered.... since they have two lenses

Compound microscopes

2

Types of compound microscopes

Bright-field
dark field

3

Lenses that work together to magnify objects

Objective and ocular

4

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

Primary magnification - real image

5

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

Ocular ... Secondary magnification

6

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

Virtual image ---- eye point

7

Total Magnification

Product of the objective and ocular lens

8

Resolving power

Resolution - limits useful magnification for compound microscopes

9

Stage

Where the specimen is placed

10

Two adjustment knobs

Course - primary focusing
Fine - secondary focusing

11

Parfocality

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

12

Working distance

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

13

As magnification increases

The field of view decreases

14

As magnification increases,

More light is needed.

15

Why is light conserved in oil?

Glass and oil have same refractive indexes

16

Absorption

Light passes through specimen

17

Refracted

Light is reflected off specimen

18

Phasecontrast

Differentiates between specimens of different densities

19

Fluorescent

Koon's fluorescent antibody technique

20

Resolving power

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

21

Magnification - resolution relationship

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

22

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

400-700nm

23

Bright field microscopy technique normally used for

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

24

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

Dark-field
Low numerical

25

Result of a dark field microscope when viewing:

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

26

Dark field microscopy is best to view

Living, unstained orgs
Examples: syphilis studies because it provides a specimen outline with reduced internal cellular details

27

Fluorescence microscope

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

28

Def; Fluorescence

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

Explain prep for fluorescent scope use

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

Wide use of fl. Microscopy

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