How Would Bacteria Appear After Staining with Crystal Violet?

What would happen if a small number of bacterial species have a preponderance of positive charges on the outside of their cells and were stained with crystal violet?

a. Purple bacteria on a clear background

b. Transparent bacteria on purple background

c. Purple bacteria on a purple background

d. Transparent bacteria on a clear background

Answer:

Staining the bacteria with crystal violet would result in purple bacteria on a clear background.

If a small number of bacterial species have a preponderance of positive charges on the outside of their cells, staining them with crystal violet would result in purple bacteria on a clear background. Crystal violet is a purple-colored dye that is widely used to stain bacterial cells, including Gram-positive bacteria. The stain binds to the peptidoglycan layer, which is a component of the bacterial cell wall, and gives a purple color to the stained cells.

This is because crystal violet is a basic dye that stains the negatively charged components of bacterial cells, such as the peptidoglycan layer in the cell wall. Bacteria with a preponderance of positive charges on the outside of their cells would still be able to retain the crystal violet stain and appear purple under a microscope. The purple background is due to the counterstain, such as safranin, used to visualize the bacteria after staining with crystal violet. The counterstain helps to distinguish between different bacterial species based on their cellular morphology and staining characteristics.