NURSING ANM AND GNM

Detailed explanation-1: -A Gram stain is colored purple. When the stain combines with bacteria in a sample, the bacteria will either stay purple or turn pink or red. If the bacteria stays purple, they are Gram-positive. If the bacteria turns pink or red, they are Gram-negative.

Detailed explanation-2: -Gram-positive bacteria characteristically stain purple following the Gram reaction, owing to their thick cell walls; this is in contrast to Gram-negative bacteria, which stain pink or red, owing to their thin cell walls.

Detailed explanation-3: -Hint:The gram-positive bacteria appear deep purple or deep violet in colour and the gram-negative bacteria appear colourless after the final step (treatment with a de-staining agent) of the gram-staining method.

Detailed explanation-4: -Gram-positive bacteria have a thick mesh-like cell wall made of peptidoglycan (50–90% of cell envelope), and as a result are stained purple by crystal violet, whereas gram-negative bacteria have a thinner layer (10% of cell envelope), so do not retain the purple stain and are counter-stained pink by safranin.

Detailed explanation-5: -Under-decolorization: If alcohol (decolorizer) is washed away before it had any effect on the cell wall, the Crystal Violet molecules will not escape the Gram-negative cell wall. As a result, all bacteria appear Gram-positive (purple) after counterstaining with Safranin.