Jameel identifies Gram-positive and Gram-negative bacteria by using the Gram staining technique. After the completion of the whole procedure, he observed under the microscope that the Gram-positive bacteria were stained purple (violet) and Gram-negative bacteria were red (pink) in colour.The reason for this difference in staining is that the cell wall of Gram-positive bacteria contains a layer that retains in staining.This layer is composed the purple crystal violet stain

Explanation

The Gram staining technique differentiates bacteria based on the structural differences in their cell walls. Gram-positive bacteria have a thick peptidoglycan layer, which retains the crystal violet stain, making them appear purple under a microscope. In contrast, Gram-negative bacteria have a thinner peptidoglycan layer and an additional outer membrane, which does not retain the violet stain but instead takes up the counterstain (safranin), appearing red or pink. The other options, such as lipoprotein, cellulose, and hemicellulose, are not involved in the Gram stain retention process in Gram-positive bacteria.