NEGATIVE STAIN Flashcards
1
Q
What dye is used for negative stains?
A
Acid dye nigrosin, it has negative charge chromophores
2
Q
Will the cells remain unstained and have a dark coloured background in the negative stain experiment?
A
Yes
3
Q
Why can’t methylene blue be used in place of nigrosin for negative stain?
A
methylene blue is a basic stain and it will adhere to the slightly negative bacteria
-> Nigrosin is an acidic stain
4
Q
What are the practical advantages of negative staining?
A
cells will retain their natural sizes and shape, therefore, not distorted by heat
5
Q
Why doesn’t nigrosin penetrate bacterial cells?
A
because it is negatively charged
