Chapter 3: Observing microorganism through a microscope

Question 1

ocular lens

Answer 1

• remagnifies the image fromed by the objective lens

Question 2

body tube

Answer 2

• transmits the image from the objective lens to the ocular lens

Question 3

Objective lens

Answer 3

• primary lens that magnifies the speciman

Question 4

Stage

Answer 4

• holds the microscope slide in position

Question 5

condenser

Answer 5

• focuses light through specimen

Question 6

Diapragm

Answer 6

• controls the amount of light entering the condenser

Question 7

Illuminator

Answer 7

• light source

Question 8

what would be the total magnification of a compund microscope with the objective lens magnification of 40x and the ocular lens of 10x

Answer 8

• 400x

Question 9

3 types of stain

Answer 9

• simple
• differnetial
• special

Question 10

simple stain

Answer 10

• aqueous or alchol solution made fo a single basic dye
  -uses a moderate

Question 11

purpose of simple stain

Answer 11

• distinguish cellular shapes or structure

Question 12

Mordant

Answer 12

• may be used to hold stain or coat the specimen to enlarge it

Question 13

Differitial stain purpose

Answer 13

• distinuish the type of bacteria

Question 14

types of differntial stains

Answer 14

• gram
• acid fast

Question 15

Gram Stain positive process

Answer 15

1. primary stain (cystal violet): purple
2. Moderant (Iodine): purple
3. Decolorizing Agent (alchol): purple
4. Counterstain (safferin): purple

Question 16

Gram stain negative process

Answer 16

1. primary stain (cystal violet): purple
2. Moderant (Iodine): purple
3. Decolorizing Agent (alchol): colorless
4. Counterstain (safferin): red

Question 17

why is there a difference in the colors of gram stain

Answer 17

• because of the diffrent makeup of the cell wall

Question 18

Acid fast stain purpose

Answer 18

• holds strong to bacteria that have waxy material
• used to identify mycobacterium species

Question 19

Acid fast positive process

Answer 19

1. primary stain (carbonfusion): red
2. Decolorizing agent (acid-alchol): red
3. counterstain (methylene blue): red

Question 20

Acid fast stain negative process

Answer 20

1. primary stain (carbonfusion): red
2. Decolorizing agent (acid-alchol): colorless
3. counterstain (methylene blue): blue

Question 21

3 types of special stains

Answer 21

1. glycocalyx
2. endospores
3. flagella

Question 22

Glycocalyx process

Answer 22

1. acidic stain: india ink or nigrosin
2. water wash (PROBLEM: water soluable capsule so have to be gental)
3. saffranin counterstain

Question 23

Endospores stain process

Answer 23

1. malachite green
2. water wash
3. counterstain: saffrinin

Question 24

flagella staining process

Answer 24

1. carbolfuchsin (red)
2. Mordant —> potassium alum (dark red)

Question 25

what is a stain?

Answer 25

- coloring the microorganism with dye that emphasizes certain structures

Question 26

Chromophore stain

Answer 26

- stains are salts; compromised of a positive and negative ion --> one of which is coloured

Question 27

Acidic dyes

Answer 27

- is the anion

Question 28

Basic dyes

Answer 28

- is the cation - used for bacteria - used most frequently

Question 29

why are basic dyes used for bacteria

Answer 29

- bacteria is slightly negativly charged therefore the cation basic dye is attracted to it

Question 30

Examples of basic dye

Answer 30

- crystal violet - methylene blue - malachite green - safffrin

Question 31

negative staining

Answer 31

- staining the background instead of the cel - useful for observing overall cell shapes, capsules, and sizes becasue distortion are limited