Question

What is Mesosome? Where is it located? What are its main uses?

Answer 1

A specialised differentiated form of cell membrane called Mesosome is the characteristic of prokaryotes. It helps in respiration.

Complete answer:
->Mesosome is an organelles formed by the infoldings of plasma membranes. They are located in bacterial cell membranes.pr
->They are invaginated structures composed of vesicles, tubules of lamellar whorls. The lamellae are formed by flat vesicles and are connected to the cell membrane.
->The lamellar whorl can be seen in Nitrobacter, Nitrosomonas and Nitrococcus.
->The vesicles are formed by invagination and tubular accretion of the plasma membrane. The structure of the vesicle becomes interrupted due to constriction at equal distance. Closely packed spherical vesicles are present in chromatium and Rhodospirillum rubrum. In some purple bacteria the vesicular bodies are flattened and stacked into thylakoids.
->They are absent in eukaryotes.
->Septal Mesosomes - It remains in contact with nucleoid & takes part in separation of replicated nucleoids & septum formation.
->Lateral or peripheral Mesosomes are equivalent to mitochondria & are called chondroid

Function of mesosomes
->They have the following functions,
->They are involved in cell wall formation.
->They are involved in DNA (chromosome) replication.
->They help in distribution of chromosomes to daughter cells.
->They take part in respiration but they are not analogous to mitochondria because they lack outer membranes. The vesicles of Mesosome have respiratory enzymes and components of electron transport such as ATPase, dehydrogenase, cytochromes are present in low amounts.
->They help in secretion processes.
->They increase the surface area of plasma membrane and enzymatic content.

Note: Mesosomes are analogous to cristae in the mitochondria in eukaryotic cells, which help in cellular respiration. Cristae is basically a fold in the inner membrane of the mitochondria.