Mesosomes, generally present in prokaryotes, are analogous to mitochondria in eukaryotes. These are folded protuberances found on the inner side of the cell membrane in prokaryotic cells. Mesosomes greatly increase the surface area of the plasma membrane and play a key role in the aerobic cellular respiration. Mesosomes are rich in respiratory enzymes and play a role similar to that of mitochondria in eukaryotic cells.
There are two types of mesosomes: septal and lateral mesosomes. The bacterial chromosome is attached to the septal mesosome. During cell division, septal mesosomes participate in cross-wall formation. Lateral mesosomes, on the other hand, are located at the periphery, unlike septal mesosomes that extend towards the center.
Apart from cell wall formation, the mesosomes are also believed to help in electron transport, cell division, DNA replication and cell compartmentalization.