Prokaryotic Cells

1. Cell wall present (bacteria) or absent (mycoplasma)

2. A prokaryotic cell is a single membrane system.

3. Cell membrane bears respiratory enzymes.

4. Mesosomes are formed by infolding of cell membrane.

5. Cytoplasm lacks membrane bound organelles

6. Ribosomes (non membrane bound organelle) are70S, lie free in cytoplasm.

7. There are no streaming movements of cytoplasm.

8. Photosynthetic lamellae i.e., thylakoids (if present) occur free in the cytoplasm.

9. Sap vacuoles are lacking. Gas vacuoles may occur.

10. Transcription and translation occur in the cytoplasm.

11. Protein synthesis takes place in cytoplasm only.

12. Cytoskeleton absent.

13. Nuclear material is not enclosed by nuclear envelope and lies directly in cytoplasm. It is called nucleoid.

14. There is no nucleolus.

15. DNA is closed and circular and without histone core (Polyamines may be present in place of histones)

16. DNA occurs in the cytoplasm only.

17. Plasmids and pili occur in many prokaryotic cells.

18. Flagella, if present, are singlet fibres (9 + 0) and are formed of a protein flagellin.

19. Mitotic spindle is not formed in cell division (Amitotic).

20. Sexual reproduction absent (recombination is present in bacteria)

21. e.g., Bacteria, blue-green algae and mycoplasmas.