Lab Exam 1 Flashcards
Identify the organism, morphology, and arrangement. What stain was used?
Micrococcus luteus
Tetracoccus
Negative stain
Identify the organism. What’s the morphology? What stain was used?
Rhodospirillum rubrum
Spirillum
Negative stain
Identify the organism. What is the morphology? What stain was used?
Citrobacter freundii
Bacillus
Gram stain (G-)
Identify the organism. What is the morphology? What is the arrangement? What stain was used?
Staphylococcus aureus
Staphylococcus
Gram stain (G+)
Identify the organism. What stain was used? What was the result?
Klebsiella pneumoniae
Capsule stain
Positive
Identify the organism. What stain was used? What was the result?
Bacillus cereus
Endospore stain
Positive
Identify organism B. What stain is used? What is the result?
Mycobacterium phlei
Acid-fast stain
Acid-fast
Identify organism A. What stain was used? What is the result?
Staphylococcus epidermidis
Acid-fast
Non-acid-fast
What organism is the red colony? What is its colony morphology?
Serratia marcescens
Moist, entire and round, convex, opaque
What organism is the “colorless” colony? What is its colony morphology?
Escherichia coli
Entire round, moist, flat, opaque
What organism is the yellow colony? What is its colony morphology?
Micrococcus luteus
Entire round, moist, convex, opaque
What organism is the yellow colony? What is its colony morphology?
Micrococcus luteus
Entire round, moist, convex, opaque
What staining technique was used?
Basic (simple) stain
What do basic stains dissociate into?
OH- and cationic chromagen
What ingredients/dyes were used for basic (simple) stains?
Methylene Blue
Crystal Violet
What organisms were viewed using basic (simple) stain?
Staphylococcus aureus
Bacillus subtilis
What staining technique is used?
Acidic (negative) stain
What do acidic stains dissociate into?
H+ and anionic chromagen
Why do we heat fix smears?
- kill all cells on slide
- adheres cells to slide
- makes cells more visible (protein denatures and conjugates)
What ingredients/dyes were used for a negative stain?
Nigrosin
What organisms were viewed with a negative stain?
Rhodospirillum rubrum
Micrococcus luteus
What do we use negative stains for?
- Hard to stain species (non-polar cell walls)
- Observe true size, morphology, and arrangement
Why does a negative stain show truer size?
No heat fixing which can distort and shrink cells
What staining technique is used?
Gram stain
What ingredients/dyes are used for gram stain?
Primary stain: Crystal Violet (basic)
Mordant: iodine
Decolorizer: Acetone-alcohol
Counterstain: Safranin (basic)
What organisms did we view under gram stain? What were the results?
Citrobacter freundii (G-B)
Bacillus cereus (G+B)
Staphylococcus aureus (G+C)
What is the differential step in a Gram stain?
Decolorization
What is a mordant for?
Color enhancer
What stain is used?
Endospore stain
What dyes/ingredients are used in an endospore stain?
Primary stain: Malachite Green (basic)
Decolorizer: water
Counterstain: Safranin (basic)
What genera produce endospores?
Bacillus and Clostridium
What organisms did we use Endospore stain on? What was the result?
Bacillus cereus: positive for endospores
Staphylococcus aureus: negative for endospores
What staining technique is used?
Capsule stain
What dyes/ingredients are used for capsule stains?
Primary stain: Tyler’s capsule stain (crystal violet)
Decolorizer: Copper sulfate
What organisms did we view with capsule stain? What were the results?
Klebsiella pneumoniae (capsule positive)
Staphylococcus epidermidis (capsule negative)
Do capsule stains use heat fixation?
No, capsules are heat-liable
What staining technique is used?
Acid-fast stain
Magenta: acid-fast
Blue: non acid-fast
What dyes/ingredients are used for acid-fast stain?
Primary stain: Carbolfuchsin (basic)
Decolorizer: Acid-alcohol
Counterstain: Methylene blue
What organisms did we view under acid-fast stain? What were the results?
Mycobacterium phlei (acid-fast)
Staphylococcus epidermidis (non-acid fast)
What are other common acid-fast bacteria? What disease do they cause?
Mycobacterium tuberculosis: tuberculosis
Mycobacterium leprae: Hansen’s disease
Mycobacterium smegmatis: smegma
What staining techniques require steam?
Acid-fast and Endospore stains
