In a typical prokaryotic cell, explain the structure 7 function of following:

1) plasma membrane

2) Capsule

3) Mesosomes

4) Flagellum

5)Pili fimbriae

Prokaryotic plasma membrane also called as the cell membrane is selectively permeable is mainly composed of proteins, phospholipids and carbohydrates, which form into a fluid-mosaic. It allows only certain ions to pass through it. It therefore, serves important role in nutrient uptake, waste removal and protein secretion
 
Mesosomes occur as extensions of plasma membrane into the cytoplasm of the prokaryotic cells. These may be in the form of vesicles, tubules, or lamellae. These are thought to be involved in many cellular processes like cell wall formation during cell division, chromosome replication and enzymatic reactions. They also help in the equal distribution of chromosomes into daughter cells.
 
Capsule:  It is made of a thick polysaccharide. It is a slime layer, which is present outside the cell wall. It is used to stick cells together and works as a food reserve and it also protects the cell from dryness and from chemicals.
 
Pili fimbriae; They are short fibre like protein appendages, which fixes bacteria to surfaces. These pili are smaller than those flagella and are used in conjugation to exchange the genetic information.
 

Flagella: They are rigid rotating tail like structures. The clockwise rotation moves the cell forward and anticlockwise rotation helps the cell to spin. The rotation is powered by H+ gradient across the cell membrane. They help in locomotion.

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