Activity 3 Staining Techniques Flashcards
____ Used to enhance visualization of structures in biological tissues under a microscope.
They are salts that color particular ___ in the bacterial cells
Acidic parts absorb -
Alkaline parts absorb -
Staining
ions
Acidic - positively charged
Alkaline - positive and negative
Before tissues are stained a ___ is prepared by ___
smear
fixing
stains to provide information about the cell size, shape, and arrangement.
The types(2)
Morphological stains
Simple stain
Negative stain
differentiate bacteria based on the chemical composition of the cell wall.
Require stains (2)
Stain used this activity
Differential stains
Primary stain
Counterstain
Gram Stain
Chemicals used: (5)
Methylene Blue Stain
Crystal Violet Stain
Grams iodine
95% ethanol
Safranin Stain
Used in a simple stain
Methylene blue
Order of Gram Stain
1 minute
1 minute
30 seconds
1 minute
Gram I - Crystal Violet
Gram II - Gram’s Iodine
Gram III - Ethyl Alcohol (decolorizer)
Gram IV - Safranin
Time of Gram Stain
Gram I - Crystal Violet
Gram II - Gram’s Iodine
Gram III - Ethyl Alcohol (decolorizer)
Gram IV - Safranin
1 minute
1 minute
30 seconds
1 minute
Color:
Gram Positive cells (3) thick peptidoglycan
Gram Negative cells (2)
Violet
Blue
Purple
Pink
Reddish
Difference between basic and acidic stains?
Basic(2)
Acidic(2)
Basic
Methylene Blue
Crystal violet
Basic carry positive charge so they bind to negative components
Acidic
Eosin
India ink
Repel from cellular components and stain the background
Basic stain makes these visible
Acidic stain makes these visible
Basic
Nucleic acids and proteins
Acidic
Capsule
Primary stain -
Imparts a purple color
Mordant -
Forms a stable complex with the primary stain
Decolorizer-
Dehydrates and shrinks gram-negative cells so the primary stain washes off
Counterstain -
Colors gram-negative cells pink
Primary stain - Crystal violet
Mordant - Iodine
Decolorizer - 95% ethanol
Counterstain - Safranin
