Class 11 NEET Biology Biological Classification Questions Part 1

(a) : Danish bacteriologists Christian Gram for the first time classified bacteria on the basis of the cell wall into two groups - Gram + ve and Gram -ve by staining with crystal violet and safranin. Gram +ve cell walls are less complex with peptidoglycan compounds and proteins and no lipids in the cell wall. Whereas in Gram -ve cell walls are more complex with peptidoglycan compounds, phospholipids and lipopolysaccharides and contains 20% lipids.