The Gram-positive bacteria appear in which color under gram staining?

Explanation

Gram-positive bacteria appear purple under Gram staining because they retain the crystal violet stain due to their thick peptidoglycan layer, which forms a stable crystal violet-iodine complex. During the decolorization step, this complex is not washed out, allowing the bacteria to retain the purple color. In contrast, Gram-negative bacteria have a thinner peptidoglycan layer and a higher lipid content in their cell walls, causing them to lose the crystal violet-iodine complex during the decolorization step and subsequently take up the red or pink safranin counterstain. Therefore, Gram-negative bacteria appear red or pink, not purple.