Question

What is a mesosome in the prokaryotic cell ? Mention the function it performs.

Answer 1

Hint: Mesosome is a characteristic circular to a villiform specialization of the cell membrane. They are analogous to cristae in the mitochondria in eukaryotic cells, which are finger- like projections and help the eukaryotic cells to undergo cellular respiration.

Complete step by step answer:
Mesosome is a convoluted membranous structure formed by the infoldings of the plasma membrane in the form of vesicles, tubules, or lamellar whorls. It is to be noted that all prokaryotic cells have Mesosomes. Prokaryotic cells have distinct nuclear envelopes and nucleolus absent. It has only a single chromosome, represented by a naked DNA, without protein. In prokaryotes, there are specific structures known as the Mesosomes. They are the invagination of the plasma membrane. These are usually in the form of vesicles, tubules, and lamellae. The folded invaginations increase the surface area of the plasma membrane. They help in cell wall formation. They even secrete various enzymes like dehydrogenase and various components of the electron transport chain. They help in DNA replication and respiration. The major function among the above all is to increase the surface area of the plasma membrane. This drastic increase in surface area of the membrane mainly helps the cell to carry out cellular respiration more efficiently. Mesosome helps in cell division, aiding cell wall synthesis, and DNA replication. Mesosomes bring the formation of this crosswalk or septum and attach the bacterial DNA to the cell membrane. This results in the separation of bacterial DNA into each of the resulting daughter cells.

Additional Information:
- In prokaryotes the chromosomal DNA is circular and histones are altogether absent.
- Membrane- bound structures such as endoplasmic reticulum, Golgi bodies, mitochondria, plastids, and lysosomes are absent
- Centrioles are altogether absent.
- Cytoplasmic microtubules and microfilaments absent.

Note:
- In prokaryotes, the centers of cellular respiration are associated with the plasma membrane. In the intracellular cytoplasmic streaming does not occur.
- They generally lack introns. Ribosomes are of the 70S type formed of 50S and 30S subunits. Cells are basic organizational units of life capable of independent existence and self multiplication.
- The smallest known cells are mycoplasmas. They are visible only with the help of an electron microscope.