NEET BIOLOGY

Detailed explanation-1: -Thus, the correct answer is ‘Cell wall.

Detailed explanation-2: -They can be distinguished by the difference in the composition of the cell wall. As the Gram (+)ve bacteria possess a cell wall made up of a thick layer of peptidoglycan without a cell membrane while the Gram (-)ve bacteria’s cell wall is composed of a relatively thin layer of peptidoglycan with a cell membrane.

Detailed explanation-3: -Gram-negative bacteria are surrounded by a thin peptidoglycan cell wall, which itself is surrounded by an outer membrane containing lipopolysaccharide. Gram-positive bacteria lack an outer membrane but are surrounded by layers of peptidoglycan many times thicker than is found in the Gram-negatives.

Detailed explanation-4: -As a result of the presence of a thick layer of peptidoglycan in its cell walls, gram-positive bacteria stain purple, by retaining the crystal violet that these cells get stained with. Due to the thin layer of peptidoglycan, the gram-negative bacteria appear pink after staining with safranin.

Detailed explanation-5: -Any alteration in the outer membrane by Gram-negative bacteria like changing the hydrophobic properties or mutations in porins and other factors, can create resistance. Gram-positive bacteria lack this important layer, which makes Gram-negative bacteria more resistant to antibiotics than Gram-positive ones [5, 6, 7].