Gram positive bacteria :
1. Their cell wall is only single-layered and 100-200 A thick.
2. They can be stained by gram stain.
3. They do not have pili.
4. In gram positive bac-teria, there are mes- osomes.
Gram negative bacteria :
1.Their cell wall consist of two layers and is 70¬120 A in thickness.
2.They cannot be stained by gram stain.
3.They do have pili.
4.In gram negative bac-teria there are no mes- osomes, If present they are poorly developed.