Question

The dyes that are used in Gram's staining are

• A. Crystal violet and methylene blue
• B. Crystal violet and safranin
• C. Crystal violet and carbol fuchsin
• D. Safranin and methylene blue

Answer 1

The correct option is B Crystal violet and safranin

The Gram's staining involves three processes: staining with a water-soluble dye called crystal violet, decolorization, and counterstaining, usually with safranin. Due to differences in the thickness of a peptidoglycan layer in the cell membrane between Gram positive and Gram negative bacteria, Gram positive bacteria (with a thicker peptidoglycan layer) retain crystal violet stain during the decolorization process, while Gram-negative bacteria lose the crystal violet stain and are instead stained by the safranin in the final staining process.