What % of gram positive cell walls are peptidoglycan?
90%
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What % of gram negative cell walls are peptidoglycan?
10%
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What order are the liquids applied in gram staining?
Crystal Violet, Gram's Iodine, Acetone, Safranin
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What does Crystal Violet do in gram staining?
Dye dissociates into CV^+ and Cl^- .....
These are taken up by both cell types where the CV ^+ ions bind and stain the negatively charged components of the bacterial cell wall. Both gram +ve and -ve cells are purple.
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What does Gram's iodine do in gram staining?
Forms complexes with CV^+ ions. Both gram +ve and -ve bacteria are purple at this stage.
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What does acetone do in gram staining?
Dissolves the lipids that make up the outer membrane of gram (1) bacteria. It dehydrates the peptidoglycan layer found in (2). The Crystal Violet- Iodine complexes cannot be retained so the dye leaks out of gram (3)
1. negative 2. both gram +ve and -ve cells. 3. negative 4. purple 5. colourless
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What does safranin do in gram staining?
Taken up by both cell types, binds to lipid cell membrane and counterstains. Gram negative go from colourless to pink
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Other cards in this set
Card 2
Front
What % of gram negative cell walls are peptidoglycan?
Back
10%
Card 3
Front
What order are the liquids applied in gram staining?
Back
Card 4
Front
What does Crystal Violet do in gram staining?
Dye dissociates into CV^+ and Cl^- .....
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