Lecture 2 Flashcards Preview

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Flashcards in Lecture 2 Deck (36):
1

name the 5 types of light microscopes

bright field
dark field
phase contrast
flourescence
differential interference contrast

2

how many occular lenses can a bright field microscope have?

one

3

occular lenses come in these 4 sizes

5x
10x
15x
20x

4

how many objective lenses can a bright field microscope have?

as many as available

5

objective lenses come in which sizes?

4x
10x
40x
100x

6

which objective power is used for scanning? which is used for oil immersion?

4x
100x

7

what is necessary for an organism to be seen under a bright field microscope?

high contrast

8

how can you make an organism easier to see under a bright field microscope?

staining

9

how do you calculate the total magnification?

ocular lens multiplied by the objective lens

10

what is numerical aperture (NA)?

it tells you how much light bends

11

how can a clearer image be achieve?

use a lower resultion/increase the numerical aperture

12

what is the smallest thing visible under a bright field microscope?

.2 micro meter or 200 nano meters

13

what color light should you use to see the smallest objects?

violet light

14

can you use the bright field microscope to see mycoplasma?

only under the best conditions

15

can you use the bright field microscope to see viruses?

no

16

can you use the bright field microscope to see bacteria?

yes

17

what modification does the dark field microscope have?

a dark field stop located just under the condensor which blocks the light except for the light around the edges

18

using a dark field microscope removes the need for __________

staining

19

can you use live specimens with the bright field microscope?

no

20

can you use live specimens for the dark field microscope?

yes

21

can you use live specimens for the phase contrast microscope?

yes

22

Name a specific example of an organism which can be seen under a dark field microscope

syphilis treponema pallidum

23

Can you seen mycoplasma under a dark field microscope?

yes

24

Name the two modifications on the phase contrast microscope that differ it from the bright field microscope

annular diaphragm
phase shifting element

25

what does the annular diaphragm do?

Generates a ring of light which initiates the bending of the light (incident rays). Located below the condenser (lets through a rind of light that helps the light to bend)

26

what does the phase shifting element do?

controlls the speed of the light by manipulating the brightness

27

using the phase contrast microscope can you see mycoplasma?

yes

28

Name the 3 modifications that a fluorescence microscope from a bright field one

exciter filter, barrier filter, fluorescent dye

29

what does the exciter filter do?

blocks out wavelengths greater than 400nm (lets through UV light only)

30

what does the barrier filter do?

blocks out wavelengths less than 500nm (protects eyes from UV light and gives a black field)

31

what does the fluorescent dye do?

absorbs high energy of the light and releases visible light. Stains things with high amounts of lipids

32

can you see mycobacterium tuberculosis?

yes

33

what is immunofluorescence?

the fluorescence antibody technique
Uses antibodys and flourescent dye for staining if there is not enough lipid for the dye to stick to the organism

34

what can you use immunofluorescence to diagnose?

syphilis

35

what modification does a differential interference contrast microscope compared to a bright field one?

uses a prism to split the light and then recombine it

36

can you see in 3D using the differential interference contrast microscope?

yes