Unit 2- Learning aim D: Practical Scientific Procedures
and Techniques
Aseptic Technique - ANSWER Prevents contamination of microbial cultures.
Purpose of Aseptic Technique - ANSWER Ensure purity and reliability of
experimental results.
Hand Washing - ANSWER First step in aseptic technique to prevent contamination.
Inoculation Loop Sterilization - ANSWER Flame until red to eliminate contaminants.
Labeling Samples - ANSWER Include date, name, test, and microorganism.
Gram Stain Purpose - ANSWER Identify bacteria based on cell wall structure.
Crystal Violet Staining - ANSWER First stain applied for 30 seconds.
Iodine Staining - ANSWER Used for 1 minute to fix crystal violet.
Decolorization - ANSWER Alcohol treatment for 15-30 seconds.
Counterstaining - ANSWER Safranin applied for 1 minute after decolorization.
Gram Positive Bacteria - ANSWER Retain crystal violet, appear purple.
Gram Negative Bacteria - ANSWER Do not retain crystal violet, appear red.
Acid-Fast Stain Purpose - ANSWER Detect mycolic acid in bacterial cell walls.
Heat Fixing - ANSWER Process to adhere bacteria to slides.
Rinsing Steps - ANSWER Involves water rinses after staining.
Blotting Dry - ANSWER Final step using paper towel after staining.
Microbial Contaminants - ANSWER Unwanted microorganisms affecting
experimental results.
Sterilization Techniques - ANSWER Methods to eliminate all forms of life.
Carbolfuchsin - ANSWER Stain used in acid-fast staining.
Counterstain - ANSWER Secondary stain applied after primary stain.
Acid-Fast Organisms - ANSWER Retain fuchsia stain due to mycolic acid.
and Techniques
Aseptic Technique - ANSWER Prevents contamination of microbial cultures.
Purpose of Aseptic Technique - ANSWER Ensure purity and reliability of
experimental results.
Hand Washing - ANSWER First step in aseptic technique to prevent contamination.
Inoculation Loop Sterilization - ANSWER Flame until red to eliminate contaminants.
Labeling Samples - ANSWER Include date, name, test, and microorganism.
Gram Stain Purpose - ANSWER Identify bacteria based on cell wall structure.
Crystal Violet Staining - ANSWER First stain applied for 30 seconds.
Iodine Staining - ANSWER Used for 1 minute to fix crystal violet.
Decolorization - ANSWER Alcohol treatment for 15-30 seconds.
Counterstaining - ANSWER Safranin applied for 1 minute after decolorization.
Gram Positive Bacteria - ANSWER Retain crystal violet, appear purple.
Gram Negative Bacteria - ANSWER Do not retain crystal violet, appear red.
Acid-Fast Stain Purpose - ANSWER Detect mycolic acid in bacterial cell walls.
Heat Fixing - ANSWER Process to adhere bacteria to slides.
Rinsing Steps - ANSWER Involves water rinses after staining.
Blotting Dry - ANSWER Final step using paper towel after staining.
Microbial Contaminants - ANSWER Unwanted microorganisms affecting
experimental results.
Sterilization Techniques - ANSWER Methods to eliminate all forms of life.
Carbolfuchsin - ANSWER Stain used in acid-fast staining.
Counterstain - ANSWER Secondary stain applied after primary stain.
Acid-Fast Organisms - ANSWER Retain fuchsia stain due to mycolic acid.
