NEET BIOLOGY

Detailed explanation-1: -Gram positive bacteria have a distinctive purple appearance when observed under a light microscope following Gram staining. This is due to retention of the purple crystal violet stain in the thick peptidoglycan layer of the cell wall.

Detailed explanation-2: -Answer and Explanation: The correct option, namely, the provided statement that is not correct with regard to Gram-positive bacteria, is option: e. Their cell walls contain lipopolysaccharides.

Detailed explanation-3: -Answer and Explanation: The correct answers are b) Gram-positive bacteria have a lot of peptidoglycan in their cell walls and stain blue to purple; e) Gram-negative bacteria have a thin cell wall and an additional outer layer with lipopolysaccharides.

Detailed explanation-4: -gram stain test Gram-positive bacteria remain purple because they have a single thick cell wall that is not easily penetrated by the solvent; gram-negative bacteria, however, are decolorized because they have cell walls with much thinner layers that allow removal of the dye by the solvent.

Detailed explanation-5: -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.