Lab Quiz 2: Gram Stain, Capsule Stain, and Endospore Stain (Bio 286 - Microbiology) Flashcards

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1
Q

Hans Christian Gram

A

developed Gram stain in 1884

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2
Q

general staining technique

A
  1. primary stain… 2. mordant… 3. decolorizer… 4. secondary stain
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3
Q

Gram stain - primary stain

A

crystal violet (1 min)

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4
Q

Gram stain - mordant

A

Gram’s iodine (1 min)

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5
Q

Gram stain - decolorizer

A

acetone alcohol (5 seconds)

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6
Q

Gram stain - secondary stain

A

safranin (1 min)

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7
Q

appearance of gram positive cells after crystal violet in gram stain

A

purple

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8
Q

appearance of gram negative cells after crystal violet in gram stain

A

purple

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9
Q

appearance of gram positive cells after gram’s iodine in gram stain

A

purple

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10
Q

appearance of gram negative cells after gram’s iodine in gram stain

A

purple

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11
Q

appearance of gram positive cells after acetone alcohol in gram stain

A

purple

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12
Q

appearance of gram negative cells after acetone alcohol in gram stain

A

colorless

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13
Q

appearance of gram positive cells after safranin in gram stain

A

PURPLE

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14
Q

appearance of gram negative cells after safranin in gram stain

A

PINK

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15
Q

primary colorizer

A

stains everything

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16
Q

mordant

A

causes primary colorizer to bind tighter

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17
Q

gram positive cells appear purple in gram stain

A

because the cell wall collapses and traps the purple dye; the purple dye overpowers the pink dye from safranin to appear purple

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18
Q

gram negative cells appear pink in gram stain

A

because the acetone dissolves the outer membrane so the purple dye dissipates, allowing the safranin to turn the now colorless cells pink

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19
Q

variable results in gram staining

A

due to age of culture, variability in amounts of peptidoglycan layer

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20
Q

difficult species to gram stain

A

spirochetes (too thin to be resolved by microscopy), mycobacterium (waxy mycolic acid layer in cell wall blocking entrance of stains), intracellular bacterial parasites (difficult to stain with analine dyes)

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21
Q

proper gram stain of gram positive bacteria

A

appears purple

22
Q

proper gram stain of gram negative bacteria

A

appears pink

23
Q

staphylococcus aureus

A

gram positive staphylcocci bacteria

24
Q

klebsiella pneumoniae

A

gram negative rod bacteria

25
Q

candida albicans

A

gram positive yeast

26
Q

enterococcus faecalis

A

gram positive streptococci bacteria

27
Q

moraxella catarrhalis

A

gram negative diplococci bacteria

28
Q

bacillus cereus

A

gram positive rod bacteria

29
Q

rhodospirillum rubrum

A

gram negative spirillum bacteria

30
Q

gram stain

A

a differential stain that classifies bacteria into two groups, gram-positive and gram-negative

31
Q

glycocalyx

A

very thin and difficult to detect layer of polysaccharide

32
Q

capsule

A

very thick and robust layer of polysaccharide; assist the cell in evading phagocytosis, as well as aggregation of cells, biofilm formation, and attachment of cells to some surfaces; can be the main virulence factor of certain mucosal pathogens

33
Q

capsule stain

A

not a differential stain; a stain that does not stain the capsule but instead stains the surroundings and the cells within the capsules

34
Q

capsule stain technique

A
  1. india ink drop on slide… 2. transfer a drop of water using sterilized loop… 3. transfer drop of species using sterilized loop… 4. spread/smear with another slide… 5. air dry BUT NO HEAT FIX… 6. cover slide with crystal violet for 1 minute… 6. rinse slide with water and allow to air dry
35
Q

endospore stain

A

A differential stain used to detect the presence and location of endospores in bacterial cells

36
Q

endospore

A

a spore produced within a vegetative cell under adverse conditions; can withstand chemical agents, antibiotics, heating, cold, and even some exposure to radiation

37
Q

endospore stain - primary stain

A

malachite green

38
Q

endospore stain - mordant

A

heat (steam bath) for 15 minutes

39
Q

endospore stain - decolorizer

A

water (1 min)

40
Q

endospore stain - secondary stain

A

safranin

41
Q

appearance of endospore after malachite green in endospore stain

A

colorless

42
Q

appearance of endospore after heat in endospore stain

A

green

43
Q

appearance of endospore after water in endospore stain

A

green

44
Q

appearance of endospore after safranin in endospore stain

A

GREEN

45
Q

appearance of vegetative cell after malachite green in endospore stain

A

green

46
Q

appearance of vegetative cell after heat in endospore stain

A

green

47
Q

appearance of vegetative cell after water in endospore stain

A

colorless

48
Q

appearance of vegetative cell after safranin in endospore stain

A

PINK

49
Q

growing the endospore-forming bacteria on more nutritious media

A

bacteria will have less endospore formation

50
Q

growing the endospore-forming bacteria on less nutritious media

A

bacteria will have more endospore formation