Pictured below is a bacterium on a microscope slide The tria

Pictured below is a bacterium on a microscope slide. The triangle on the left represents a particle of an aniline dye like crystal violet; the square on the right represents a particle of an acidic dye like nigrosin. Add the appropriate positive or negative charge symbols to all four areas of the drawing (bacterium, slide, aniline dye, acidic dye), then draw arrows between the stains and their targets to indicate the surfaces that will be colored by each dye.

Solution

Principle of staining:

1. Basic Stain (+ve charge): To stain negative charged molecules of bacteria. Mostly used because cell surface of bacterium is negative. For example: Crystal violet

2. Acidic Stain (-ve charge): To stain positively charged molecules of bacteria. Used to stain bacterial capsules. Example: Nigrosin

So, triange is +ve and square is -vely charged. Bacterial slide is -vely charged.