Ch.3 Microscopy And Staining

Question 1

Defined the term microscopy

Answer 1

Do use of a microscope

Question 2

What is the basic unit of measurement in microbiology what is the size range of most bacteria

Answer 2

Micrometer between 0.2 and 1.0 µm

Question 3

How do you determine the total magnification of for a microscope

Answer 3

Objective lens x the ocular lens equals the total magnification

Question 4

Define resolution what are the factors that affect resolution

Answer 4

The ability of lens to distinguish 2 points resolving power shorter wavelengths of light provide a greater resolution

Question 5

Why is it necessary to use immersion oil to 10 the best results with the microscope define refractive index

Answer 5

It is is to keep light from bending before it enters the objective lens

refractive index is the light bending ability of a medium for example air has different refractive index compared to oil

Question 6

Bright field

Answer 6

Dark objects are visible against a bright background

Question 7

Dark field

Answer 7

Light objects against dark background

Question 8

Phase contrast

Answer 8

Used for viewing internal structures of cells in natural state

Question 9

Florescence

Answer 9

Uses UV light to view cells stained with flurochromes

Question 10

Confocal

Answer 10

Uses laser light and produces 3-D image

Question 11

Differential interference contrast

Answer 11

Accentuates light diffraction and uses 2 light beams

Question 12

Electron microscopy

Answer 12

Used to see virus is not useful for observing living cells because it requires a thinly sliced section and there’s too high of energy

Question 13

Identify the uses of each type of electron microscopy

Answer 13

TEM transmission electron microscope stand with heavy metal salt use is thin slices

SEM Scanning electron microscope beam of electrons the skin whole specimen

Question 14

Scanning probe microscopy

Answer 14

Can see DNA is this metal prologue to scan specimen

Question 15

Define staining

Answer 15

Consist of positive and negative Ion

Base dye cat ion positive Acidic die anion negative

Question 16

How are smears prepared

Answer 16

Thin film of microbes heat fixed onto a slide

Question 17

Give an example of basic an acidic die and explain how they interact with bacteria to produce a stain

Answer 17

Basic days basic fusion crystal violet malachite green methanol blue safranin die goes into cell

Acidic days acidic fusion eosin Rose Bengal, nigrosin repelled by negative charge of cell wall Creating a negative stain

Question 18

How are negative stains prepared

For what application is this type of stain especially useful for

Answer 18

Using a acidic die - repels with negative charge cell wall staining background

More accurate for size and to see the capsule better which is the outside bubble

Question 19

What is the primary purpose of a simple stain

Answer 19

Help determine shape size and arrangement use basic die cat ion that is attracted to the cell wall

Question 20

What is a differential staying

Answer 20

Example Graham and acid-fast stains specific type of stand that allows for microbe identification and distinguishing between cells and I mixed sample

Question 21

Describe the steps of the gram staining procedure

Answer 21

After shmear is made and heat fixed apply primary stain Crystal violet add iodine which binds crystal violet and traps in the cell then use rapid decolorization with ethanol or acetone for 10 seconds counter stand with saffron se then blot

Question 22

What is a mordant used for in Gram stain

Answer 22

Iodine is used to fix the crystal violet to the bacterial cell wall

Question 23

In a correct Gram stain what is the color of gram-positive cells and Graham negative cells

Answer 23

Gram-positive is purple Graham negative is red

Question 24

What is the relationship between cell wall structure and the Gram stain

Answer 24

Gram-positive thick cell wall monoderm inside and small

Graham negative thin cell wall surrounded by two diderms more resistant to antibodies because of an impenetrable wall

Question 25

What is the purpose and principle of the acid-fast stain

Answer 25

Differentiates cell based on mycolic acid which is a waxy lipid that prevents/slows the entry of hydrophilic material

Positive red negative blue

Uses acid alcohol as decolorizer my colic acid holds onto color

Question 26

Name two important human pathogen’s that are acid-fast

Answer 26

Micro bacteria tuberculosis and leprosy

Question 27

What is the purpose of the endospore stain

Answer 27

Differential stain to visualize bacteria endospores that are formed by a few genre of bacteria such as bacillus by forming spurs back to you I can survive and hostile conditions