The nucleus of the bacterial cell is
not well-organised like the cells of
multicellular organisms. There is no
nuclear membrane. The cells having
nuclear material without nuclear
membrane are termed prokaryotic
cells. The organisms with these kinds
of cells are called prokaryotes (pro :
primitive; karyon : nucleus). Examples
are bacteria and blue green algae. The
cells, like onion cells and cheek cells
having well-organised nucleus with
a nuclear membrane are designated
as eukaryotic cells. All organisms
other than bacteria and blue
green algae are called eukaryotes.