staining Flashcards
what is gram negative
2 outer membranes with thin peptidoglycan
what colour is it stained
pink
not stained by cv but by safranin so pink
what is gram positive
1 outer thick membrane with peptidoglycanon outside
how to carry it out
attach bacteria to glass slide
using bacteria culture then using heat to fix it
add crytsal violet solution
add iodine
alcholol wash
counter stain with safrnain staining everything pink
what does cystal violet solution do
enter the cell wall
what does iodine form
larger complex with the cv
what does the alcohol do
dehydrates pepditogylcan layer = tightened
in gp the crystal violet and iodine can’t leave so theyre
stained with cv so are purple
gn the cv iodine complex washed out - lose cv stain
what coulour is gp
purple
the cv and iodine aren’t washed out
what are shperes called
coccus
coccus
dicooci
staphcocci
round ended cylinders
bacillus
what are hemolysins
enzymes that are released by bacteria that can damage red blood cells
hemolytic activity is useful for differentiating which species
gp
what is gamma hemolysis
g no hemoysis- no zone
alpha partial- opaque zone
b complete - transparent zone
how to test ha
growth on compplex medium containig 5% sheep red blood cells
shows if the b produces hemolysins
lactose fermantation is useful to diff gn
yes - if it can use lactose for growth
