Lab Stains

Question 1

What is in a Simple Stain?

Answer 1

Solvent and Chromogen

Question 2

What is the function of a Chromophore?

Answer 2

Provides color

Question 3

What is the function of Auxochrome?

Answer 3

Binds color to the cell

Negatively charged–binds to positive charge of basic stains

Question 4

What stains can you use in a Simple Stain?

Answer 4

Methylene Blue
Safranin
Crystal Violet

Question 5

What are the steps of a Gram Stain?

Answer 5

1. Primary Stain–Crystal Violet
2. Mordant–Iodine
3. Decolorizer–Ethanol
4. Counter Stain–Safranin

Question 6

What color is a Gram Positive cell?

Answer 6

Purple

Question 7

What color is a Gram Negative cell?

Answer 7

Pink

Question 8

What kind of cell needs Acid-Fast Staining?

Answer 8

Mycobacterium

• Lipid-producing bacteria
• Cells have Mycolic Acid layer in cell wall

Question 9

What stains are used in Acid-Fast Staining?

Answer 9

1. Carbolfuchsin Stain–Keep Moist!
2. Decolorizer
3. Counterstain–Methylene Blue

Question 10

What kind of cell needs Capsule Staining?

Answer 10

Cells with a capsule–Glycocalyx

Will show white circle around cell body

Question 11

What is the purpose of glygocalyx?

Answer 11

1. Capsule = Protection, inhibits phagocytosis

2. Slime Coat = Attachment, biofilm formation

Question 12

What stains are used in Capsule Staining?

Answer 12

1. Congo Red

2. Maneval’s