Question

Pre-Lab Questions:

1. After staining what color will Gram positive bacteria be? What color will Gram negative bacteria be?

2. What structure is more prominent in Gram positive bacteria than Gram negative bacteria?

3. Why should I not spray water aggressively or directly on my bacteria on my slide?

Answer 1

1) After staining , the color of gram positive bacteria is purple because they retain crystal violet dye

2) The color of gram negative bacteria will be pink because they retain counter stain safranin

3) In gram positive bacteria , several layers of peptidoglycan are present which make the cell wall very thick , whereas in gram negative bacteria , there is single layer of peptidoglycan so cell wall is very thin

4) water should not aggressively poured on slide because water fall directly on smear and smear gets destroyed and there is no use of doing the experiment , so to keep the smear intact water is poured slowly along the surface of the slide