Microbio Chapter 3- Microorganisms through a microscope Flashcards
What kind of stain is used to stain bacteria?
Basic
What is the exception for a basic stain?
Glycocalyx uses acidic stain
What are the types of stains?
Simple
Differential
Special
What kind of dye is used for simple stains?
Single basic dye
What is the purpose of using simple stain?
Highlight the entire microorganism
-cellular shapes and basic structures are visible
What is the purpose of a mordant?
Intensify the stain
What is the function of a mordant?
Increase the affinity and increase thickness
What are differential stains?
react differently depending on which bacteria is stained
What do differential stains distinguish between?
Gram-stains and Acid-fast stains
What are Gram-stains primary stain?
Crystal violet
What colour does crystal violet turn the bacteria?
Purple
What is the mordant used for gram stains?
Iodine
What colour does iodine turn the bacteria?
Stays purple
What is the decolourizing agent in gram stains?
Alcohol: Acetone or 95% ethanol
What colour does gram positive turn when the decolonizing agent is introduced?
Stays purple
What colour does gram negative turn when the decolorizing agent is introduced?
becomes colourless
What is the counterstain used for gram-stains?
Safranin
What colour does gram positive turn when the counterstain is applied?
Stays purple
What colour does gram negative turn when the counterstain is applied?
Red/pink
What is an acid-fast stain?
Only binds to waxy material in cell walls (Mycobacterium species - Mycolic acid)
What is the primary stain in Acid-fast staining?
Carbolfuchsin and is then heated
What colour does carbolfuchsin turn the bacteria?
Red
What is the decolorizing agent of acid fast stains?
Acid-alcohol
What bacteria becomes colourless when the decolorizing agent is applied in acid fast stains?
NON-acid fast
What happens to acid-fast bacteria when the decolorizing agent is applied?
Stays red
What is the counterstain used for acid-fast stains?
Methylene blue
What colour does Acid-fast bacteria turn when methylene blue is applied?
Stays red
What colour does non-Acid-fast bacteria turn when methylene blue is applied?
Turns blue
Examples of bacteria stained by acid-fast stains?
TB and leprosy
what are the types of special stains?
Glycocalyx/capsule stain
Endospore stain
Flagella stain
Is the primary stain used for capsule staining acidic or basic?
ACIDIC
What is the primary stain used for capsule stain?
India Ink or Nigrosin
What is the purpose of India ink and nigrosin?
Provides a contrasting background after the water wash
What is the counterstain used for capsule staining?
Safranin
What is the primary stain for endospore staining?
Malachite green after being heated
What is the counterstain used for endospore stains?
Safranin (turn red) after water wash
What is the primary stain used for flagella stains?
Carbolfuchsin
What is the mordant used for flagella stains?
potassium alum (turns dark red)
