The cell is the considered to be the basic unit of all organisms, cell is considered to be the structural and functional unit of life, and human beings are multi cellular the cell plays the active part in all the biological activities that happen in the human body. Normally the each cell is divided into two major categories, one is prokaryotic, which are simpler in structure and eukaryotes which contains the well defined nucleus and are considered to be complex in structure. The each cell is covered by a plasma membrane, in the prokaryotic cells , this prokaryotic cells are simpler and smaller and it has no nucleus, there are two types of prokaryotic cells , one is bacteria and archaea but where as the eukaryotic cells will consists of a well defined the nucleus.