Chapter 4 Microscopy, Staining, and Classification

Question 1

Principles of Microscopy (4)

Answer 1

1 wavelength
2 magnification
3 resolution
4 contrast

Question 2

Wavelength

Answer 2

length between 2 crests of light

Question 3

visible light spectrum

Answer 3

(purple, short) 400nm - 700nm (red, long)

Question 4

Magnification

Answer 4

process of enlarging something in appearance

Question 5

Resolution

Answer 5

how close 2 points in the image can be before they are no longer seen as 2 separate points

clarity of an image

Question 6

Contrast

Answer 6

difference of intensity bw 2 objects or an object and its background

Question 7

Simple Bright-Field Microscope

Answer 7

• light microscopy
• single magnifying lens
• similar to magnifying glass
• leeuwenhoek used simple microscope

Question 8

Compound Bright-Field Microscope

Answer 8

• light microscopy
• series of lenses for magnification
• light passes thru specimen into objective lens
• oil immersion lens increases lenses
• 1 or 2 ocular lenses
• may have condenser lights

Question 9

Total Magnification

Answer 9

(objective lens)x(ocular lens)

Question 10

Dark-Field Microscopes

Answer 10

• light microscopy
• best for observing pale/unstained objects
• only light rays scattered by specimen enter the objective lens
• specimen appears light against dark background
• increases contrasts and enables observation of more details
• ideal for visualizing spirochetes

Question 11

Electron Microscope

Answer 11

• greater resolving power and magnification
• 10,000x to 100,000x
• detailed view of bacteria, viruses, ultrastructure, and large atoms

Question 12

Light Microscopes

Answer 12

-cannot resolve images closer than 200nm

2 types: bright-field and dark-field

Question 13

2 types of Electron Microscopes

Answer 13

1 Transmission Electron Microscopes (TEM)

2 Scanning Electron Microscopes (SEM)

Question 14

Transmission Electron Microscopes (TEM)

Answer 14

• 2D images

- cross sectional

Question 15

Scanning Electron Microscopes (SEM)

Answer 15

• 3D images

- topographies

Question 16

Probe Microscopy

Answer 16

-magnifies more than 100,000,000x (one hundred million)

Question 17

2 Types of Probe Microscopy

Answer 17

1 Scanning Tunneling Microscopes

2 Atomic Force Microscopes

Question 18

Principles of Staining

Answer 18

• staining increases contrast and resolution by coloring specimens with stains/dyes
• smear of microorganism (thin film) made prior to staining
• microbiological stains contain chromophore
• acidic dyes stain alkaline structures
• basic dyes stain acidic structures

Question 19

3 types of Staining

Answer 19

1 Simple Stains
2 Differential Stains
3 Special Stains

Question 20

4 types of Differential Stains

Answer 20

1 Gram Stain
2 Acid-Fast Stain
3 Endospores
4 Histological Stains

Question 21

2 types of Special Stains

Answer 21

1 Negative (Capsule) Stain
2 Flagellar Stain

Question 22

Gram Stain Procedure

5 steps

Answer 22

(+)...............................(-)
(...)......heat fix.......(...)
(pu)..crystal violet..(pu)
(pu).gram's iodine.(pu)
(pu)....decolorize....(...)
(p)red counterstain(pi)

Question 23

Acid-Fast Stain

Answer 23

• acid-fast organisms have wax-like, impermeable cell walls

- mycobacterium i.e. tuberculosis

Question 24

Endospore Stain

Answer 24

• staining and visualizing endospores
• endospores can survive even the harshest conditions
• allows us to see if endospores are present
  ex) anthrax, tetanus

Question 25

Histological Stains

Answer 25

- hematoxylin and eosin (H&E) -purp | - gomor methenamine silver (GMS) - blue

Question 26

Negative (Capsule) Stain

Answer 26

- "special stain" - detects the presence of bacterial capsules - see bacterium right away

Question 27

Flagellar Stain

Answer 27

- "special stain" | - flagella is normally too thin/small to be seen w normal staining technique

Question 28

Staining for Electron Microscopes

Answer 28

- requires stains that contain heavy metals - helps absorb and reflect electrons - stains may bind moles in specimens or backgrounds - heavy metal will kill specimen

Question 29

Linnaeus

Answer 29

- classified organisms based on common characteristics - "species" - "binomial nomenclature - only proposed 2 kingdoms (now there's 5)

Question 30

Species

Answer 30

- created by Linnaeus | - organisms that can successfully interbreed

Question 31

Taxonomic identifying characteristics

Answer 31

``` 1 physical characteristics 2 biochemical tests 3 serological tests 4 phage typing 5 analysis of nucleus acids ```

Question 32

Taxonomy order

Answer 32

``` 8 Domain 7 Kingdom 6 Phylum 5 Class 4 Order 3 Family 2 Genus 1 Species ```

Question 33

Agglutination Test

Answer 33

a type of serological test - neg result = antibodies won't clump - pos result = clumping of antibodies and bacteria

Question 34

Phage Typing

Answer 34

- a bacterial lawn and a bacteriophage is applied to see if the bacteria is susceptible to phage - if there are plaques (holes on the lawn), then the bacteria is susceptible