Microbiology Lab Practical #1 Review Exam 2025 Questions & Answers with 100% Correct Answers | Verified

Bacterial Smear - Allows better visualization of specimens using microscopy. Heat Fixing - kills organisms, keeps organisms stuck to slide, allows the specimen to be stained more easily Aseptic Technique - preparing and handling sterile products in a manner that prevents microbial contamination Gram Staining Procedure - 1. Heat fix bacterial smear 2. Cover with Crystal Violet (Primary Stain) and wait 60 seconds 3. Rinse slide with distilled water until stain is removed 4. Cover with Gram's Iodine (Mordant) and wait for 60 seconds 5. Rinse with distilled water 6. 2-3 drops of Decolorizer (95% Ethanol), or until color is clear, rinse with distilled water 7. Cover with Safranin (Counter Stain) and wait 45 seconds 8. Rinse with distilled water 9. Blot dry with Bibulous paper, observe under oil immersion and record results Capsule Stain Procedure - 1. Agitate broth culture 2. 2-3 loop fulls of broth culture added to slide and allow to air dry (NOT HEAT FIXING) 3. Cover with Crystal Violet (Primary Stain) and wait for 2 minutes 4. Rinse with 20% Copper Sulfate Solution (Decolorizer and counter stain) 5. DO NOT RINSE WITH WATER 6. Air dry for a few minutes and DO NOT BLOT Observe under oil immersion and record results Why do you not heat fix during the capsule stain procedure? - Heat will cause the capsule to dislodge