Question

Which of the following is not true about Gram staining?

a) After staining, bacteria are pin

b) Gram positive bacteria have thicker walls than Gram negative bacteria

d) Gram staining seperated bacteria into their distinct groups

Answer 1

Ans.

Option (a) is not true.

because Gram staining seperated bacteria into their distinct groups, Gram positive and Gram negative bacteria.

after staining when bacterias are washed out by ethanol, only Gram positive baterias retain stain of crystal-voilet in their cell wall because Gram positive bacteria have thicker cell wall made up of peptidoglycon.

while gram negative bacterias does not retain stain in their cell wall because of thinner cell wall.

hence all options are correct except first.

because after staining bacterias are not pinned.