Mesosomes are the invaginations of which bacterial cell structure?

Explanation

Mesosomes were once thought to be infoldings of the plasma membrane found in some bacteria, particularly Gram-positive species, and were believed to play roles in cell division, respiration, DNA replication, and nutrient absorption by increasing the surface area of the cell membrane. They were hypothesized to help anchor the cell division machinery, contain respiratory enzymes, and assist in organizing the bacterial chromosome during replication. However, subsequent research has demonstrated that mesosomes are artifacts resulting from chemical fixation techniques used during electron microscopy sample preparation. Therefore, they are not considered part of the natural structure of bacterial cells.