Q.What is a mesosome in a prokaryotic cell? Mention the functions that it performs

Picture a plain room whose walls you suddenly fold inward in pleats, like pushing a curtain into the space. You have not added any new material, yet the room now has far more wall surface than before — and if useful machinery is mounted on those walls, you have just multiplied how much work the room can do. A mesosome is this idea applied to a bacterial cell.

A mesosome is a special, differentiated form of the cell membrane found in prokaryotes. Instead of the membrane staying as a simple smooth boundary, parts of it fold and push inward into the interior of the cell, forming extensions shaped as vesicles, tubules and lamellae. Because it is built from the membrane itself, a mesosome is not a separate membrane-bound organelle of the kind eukaryotes have — it is the cell's own membrane reorganised into a more active, in-folded structure.

These infoldings are useful precisely because they add surface and carry membrane enzymes. A mesosome helps a prokaryotic cell with several jobs at once:

• Cell wall formation — assisting in building the wall.
• DNA replication and distribution — helping copy the genetic material and hand it out fairly to the two daughter cells during division.
• Respiration — supporting the cell's energy-releasing reactions.
• Secretion — helping move substances out of the cell.
• Increasing surface area — enlarging the plasma membrane's area and boosting its enzyme content. …