Introduction Mycoplasma are unique smallest free-living organism capable of self-replication no peptidoglycan cell wall able to deform into a wide range of shapes antibotics that attack the cell wall don't work penicillin and cephalosporins do not work cholesterol found in cell membrane the only bacterial membrane containing cholesterol however, does not synthesize cholesterol requires cholesterol for in vitro culture culture on Eaton's agar "fried-egg" appearance except M. pneumoniae 2 pathogenic species M. pneumoniae Ureaplasma urealyticum