Chapter 2

Question 1

What is acid-fast staining?

Answer 1

Stain’s members of genus Mycobacterium,

Mycolic acid in cell walls for staining

Question 2

Endospore staining

Answer 2

heated, double staining

bacterial and vegetative are different colours

Question 3

Flagella staining

Answer 3

mordant applied to increase thickness of flagella

Question 4

Capsule staining

Answer 4

visualize polysaccharide capsules around bacteria

-ve stain = colourless capsules against stained background

Question 5

Electron Microscopy

Answer 5

electrons instead of light = illuminating beam

d=0.15/nsin(theta)

Question 6

TEM

Answer 6

Transmission Electron Microscope

electrons scatter after they past specimen, under vacuum, denser = scatter more

Question 7

Specimen Preparation

Answer 7

specimen cut very thin
chemically fixed
stained with e dense materials (heavy metals)

Question 8

Negative Stain

Answer 8

heavy metals do not penetrate specimen,
dark background
(virus, bacterial gas vacuoles)

Question 9

Shadowing

Answer 9

coating specimen with thin film of heavy metal(ONE SIDE ONLY)
(viral morphology, flagella, DNA)

Question 10

Freeze-etching

Answer 10

Freeze, and fracture along lines of weakness

3D observation of intracellular

Question 11

Scanning electron microscope

Answer 11

e excited from surface of specimen to create detailed image

3D surface features

Question 12

Electron Cryotomography

Answer 12

Rapid freezing technique,
preserve -ve state of structures in vacuum
many images - 3D structure
(cytoskeleton, magnetosomes, inclusion bodies, flagellar motors, viral structures)

Question 13

Scanning Probe Microscopy

Answer 13

>Scanning tunneling microscope 
magnify 100 mill times 
(atoms on surface of solid) 
steady current (tunneling) between microscope and specimen 
Up/Down movement 

> Atomic force microscope
-sharp probe movements under surface of specimen at constant distance
up/down movement