Define Prokaryotic Cells.


The word prokaryote is derived from the Greek where "pro" means 'before' and "karyote" means the nucleus. Thus, prokaryote means a primitive type of nucleus.

A prokaryote is a unicellular organism with a primitive type of nucleus. Prokaryotic cell lacks a membrane-bound nucleus, mitochondria, and any other membrane-bound organelle. Prokaryotes are further divided into, Archaea and Bacteria.

 

The components of prokaryotic cells are as mentioned:

 

1. Plasma membrane: An outer covering that separates the cell’s inner environment from its surrounding environment.

 

2. Cytoplasm: It consists of the jelly-like cytosol present inside the cell, along with the cellular structures suspended in it.

 

3. DNA or RNA: It is the genetic material of the cell. The majority of prokaryotic DNA is found in the nucleoid and consists of a single large loop known as a circular chromosome.

 

4. Ribosomes: Single membrane structures that synthesize proteins.

 

5. Cell Wall: The majority of the bacteria are surrounded by a cell wall made of peptidoglycan (a polymer of linked carbohydrates and small proteins). The function of the cell wall is to provide an extra layer of protection, maintain cell shape, and prevents dehydration. Few bacteria also possess capsule which is sticky, an outermost layer of carbohydrates that helps the cell attach to surfaces in its environment.

 

6. Flagella: Whip-like structures that act as rotary motors to help bacteria move.

 

7. Fimbriae: Hair-like structures used for attachment to host cells and other surfaces.

 

8. Pili: Rod-like structures that allow a bacterium to transfer DNA to other bacteria, and sometimes they function in bacterial locomotion.


                

Updated on: 10-Oct-2022

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