Microbiology Lab – Stains Exam Questions and Answers 100% Pass

Microbiology Lab – Stains Exam Questions and Answers 100% Pass Simple stain - -Add color to cells for viewing -Highlight entire organism's shape and basic structures -Includes: Methylene blue Safranin Crystal violet Carbolfuchsin Negative stain - -Enhances viewing of morphology, capsules -Bacteria are live -No heat fixing! (no denaturing) 2 100% Pass Guarantee Katelyn Whitman, All Rights -Nigrosin ink -View under oil -Anionic (acidic) simple stain Gram stain - -Determines cell wall type (gram positive or negative) -Differential stain Gram stain procedure - 1. Crystal violet 2. Iodine (mordant) 3. Alcohol (decolorizer) 4. Safranin (counterstain) 5. Observe under oil Mordant - gram stain - -Increases intensity of crystal violet -Iodine enters cell forms crystal violet-iodine complex (CV-I) -Complex is too large to leave the cell Alcohol - gram negative - -Decolorizer 3 100% Pass Guarantee Katelyn Whitman, All Rights -Dissolves lipids in the outer membrane -Allows CV-I complex to leave cell, making it colorless Safranin - gram stain - -Counter stain -Will only stain gram negative cells Alcohol - gram positive - -Decolorizer -Dehydrates thick layer of peptidoglyca