Which of the following helps in respiration, secretion process and increase the surface area for enzymatic content in bacteria ? 

A special membranous structure is the mesosome which is formed by the extensions of the plasma membrane into the cell. These extensions are in the form of vesicles, tubules, and lamellae. They help in cell wall formation, DNA replication, and distribution to daughter cells. 

They also help in the respiration, secretion process, and increase the surface area of the plasma membrane for enzymatic content in bacteria.