Q.
Which among the following are the smallest living cells, known without a definite cell wall, pathogenic to plants as well as animals and can survive without oxygen?
The prokaryotic cell is represented by Bacteria, BGA, PPLO (pleuropneumonia like organism)/Mycoplasma. Mycoplasma is the smallest/simplest organism capable of autonomous growth and reproduction. It has a size of 0.1 microns. They are the smallest living cells. Mycoplasma is deprived of the cell wall and has trilamellar unit (cell) membrane, which has a high concentration of sterol. They are highly pleomorphic and can assume various shapes like spherical, granular, filamentous, coccoid, etc. They are pathogenic in plants and animals. They can survive without any oxygen.