Answer:
wall
Explanation:
Hans Christian Gram, a Danish bacteriologist, studied and defined the technique for staining bacteria, the Gram stain, in 1884. On this occasion, he experimentally stained slides with smears (a roughly speaking "scratch" of a particular place on the body). or from a culture to be researched) with gentian violet and realized that if the bacteria in these smears once stained did not fade with alcohol, if they were previously treated with iodine.
Advancing and refining the method, he added other dyes called “counterstains” such as safranin and basic fuchsin. The bacteria contained in the smear can be classified as Gram positive (approximately purple) or Gram negative (approximately red), this will depend on the bacterial cell wall. If it is the structurally simple bacterial wall the staining will be positive, if it is structurally complex the staining will be negative.
Gram-negative bacteria have a thinner, less complex wall of polysaccharides, so they do not absorb the stain used in the test. Gram-positive bacteria, however, have a thicker and more complex wall of polysaccharides and therefore absorb staining.