Microbiology Lab – Stains Exam Questions
And Answers 100% Pass.
Simple stain - Answer✔-Add color to cells for viewing
-Highlight entire organism's shape and basic structures
-Includes:
Methylene blue
Safranin
Crystal violet
Carbolfuchsin
Negative stain - Answer✔-Enhances viewing of morphology, capsules
-Bacteria are live
-No heat fixing! (no denaturing)
-Nigrosin ink
-View under oil
-Anionic (acidic) simple stain
Gram stain - Answer✔-Determines cell wall type (gram positive or negative)
-Differential stain
Gram stain procedure - Answer✔1. Crystal violet
2. Iodine (mordant)
3. Alcohol (decolorizer)
4. Safranin (counterstain)
5. Observe under oil
Mordant - gram stain - Answer✔-Increases intensity of crystal violet
-Iodine enters cell forms crystal violet-iodine complex (CV-I)