Mesosomes are special membranous structure formed by the extension of plasma membrane. These extensions are in the form of vesicles, tubules, and lamella Functions (1) They help in the formation of cell wall (2) They take part in the replication of and distribution DNA to the daughter cells. (3) Mesosomes help in respiration, and secretion processes. (4) They increase the surface area of the plasma membrane and enzymatic content.