Mesosomes are present in both gram-positive and gram-negative bacteria. Mesosomes of gram-negative cells typically are lamellar and are fewer in number and less extensively developed than those of gram-positive bacteria.

Is Mesosome present in all bacteria?

All prokaryotic cells have mesosomes. Prokaryotic cells have different types of nuclear envelopes and nucleolus is not present.

Do all prokaryotes have a Mesosome?

Mesosomes are structures of prokaryotic cells formed by folded invaginations (sometimes described simply as "infoldings") of the plasma membrane. Enzymes associated with respiration of the prokaryotic cell, e.g. a bacterium, are located on the infoldings. Not all prokaryotic cells have mesosomes.