Final answer:
Crystal violet dye binds to the peptidoglycan protein present in the cell membrane of Gram-positive bacteria, making them appear purple during Gram staining. Gram-negative bacteria appear pink due to the uptake of the pink dye safranin.
Step-by-step explanation:
Crystal violet dye binds to the peptidoglycan protein present in the cell membrane of Gram-positive bacteria. Gram-positive bacteria have a thick cell wall without an outer membrane, allowing them to retain the purple crystal violet dye during the Gram stain process. This is why they appear purple. On the other hand, Gram-negative bacteria have an outer membrane that dissolves during the decolorization step, causing them to take up the pink dye safranin and appear pink.
Purple violet binds to the peptidoglycan in the cell walls of gram-positive bacteria, which retain the purple color after Gram staining due to their thick cell wall compared to gram-negative bacteria that stain pink because their thinner cell wall does not retain the dye.
Purple violet binds to the peptidoglycan protein present in the cell membrane of gram-positive bacteria. During the Gram stain process, all bacteria are initially stained purple because of the crystal violet dye. However, after the addition of alcohol, which serves as a decolorizer, the thicker cell wall of gram-positive bacteria retains the dye, whereas it is washed out in gram-negative bacteria. Subsequently, gram-negative bacteria are counterstained with safranin and appear pink. This differential staining is due to the differences in the cell wall structure, where gram-positive bacteria have a thick peptidoglycan layer that traps the crystal violet-iodine complex, while the thinner cell wall and outer membrane of gram-negative bacteria allow the dye to escape.