Staining

See the attachment first, here's what I found from it.

The ability of the bacteria to resist decolorization with ACID alcohol confers acid fastness to the bacterium. Acid-fast bacteria, of which there are very few---the major genus Mycobacterium, have a high concentration of mycolic acid, a lipid, in their walls. Although difficult to stain, once the stain goes into the wall, the cell will not de-stain or decolorize easily. The ability of the bacteria to resist decolorization with acid (1%) alcohol confers acid -fastness to the bacterium. It is thought that the phenol in the carbon fuschin facilitates the dye going into the waxy wall of the bacterium. Although gram positive, acid-fast bacteria do not take the crystal violet into the wall well, appearing very light purple rather than the deep purple of normal gram positive bacteria (the waxy lipid in the acid-fast wall repels the aqueous crystal violet stain).