What is "mesosome"

a. Average-bodied; neither broad nor narrow in proportion to height or length. n. A folded invagination in the plasma membrane of bacteria, produced by the chemical fixation techniques used to prepare samples for electron microscopy, but previously thought to be part of the normal structure of the cell.

Mesosomes are folded invaginations in the plasma membrane of bacteria that are produced by the chemical fixation techniques used to prepare samples for electron microscopy. Although several functions were proposed for these structures in the 1960s, they were recognized as artifacts by the late 1970s and are no longer considered to be part of the normal structure of bacterial cells. Mesosomes is the site of chromosomal attachment during cell division.