Describe the differences between gram-positive and gram-negative organisms.

Gram-negative bacteria differ from gram-positive bacteria in the structure of the outer integument of the cell. They contain a cell wall, which is located in the periplasmic space, that is, in the space located between two membranes, inner and outer. The cell wall is composed of a heteropolymer called peptidoglycan. The outer membrane, in addition to the phospholipids inherent in the composition, also contains lipopolysaccharide (polysaccharide and lipid, connected by covalent bonds). Gram-negative bacteria, due to the presence of a cell wall, which prevents the ingress of the dye into the cell, do not stain according to Gram into crystalline pheoletic, the bacteria discolor after washing off the stain with alcohol. After the addition of the safranin dye, the bacteria turn red.