The characteristic features of the mycoplasma are that
(1) they are much smaller than bacteria in size
(2) they can be grown on cell free medum
(3) they are highly pleomorphic and are bounded by a triple layered unit membrane
(4) all of the above
(4) Mycoplasma are 'pleuro pneumonia like organisms' or PPLO, which lack cell wall and have no shape (i.e., pleiomorphic) cell membrane is 3-layered made up of lipoproteins. They were first isolated from bovine sheep, suffering from pleuropneumonia. The human infertility and abortions are now known to be due to mycoplasma infections of the urinogenital tract. Mycoplasma may be saprophytic, parasitic or pathogenic. They can grow on culture media and form colonies. They pass through bacteria-proof filters, so they are the smallest, free living, microorganisms.