The cell is the basic structural and functional unit of all known living organisms. It is
the smallest unit of life that is classified as a living thing. Some organisms, such as most
bacteria, are unicellular (consist of a single cell). Other organisms, such as humans, are
Robert Hocke discovered the cell when he was watching the cork in the microscopy.
There are two types of cells: eukaryotic and prokaryotic. Prokaryotic cells are usually
independent, while eukaryotic cells are often found in complex organisms. In all cells
we can differentiate three parts: the cell membrane, the cytoplasm and the genetic
The prokaryotic cell is simpler, and therefore smaller, than a eukaryote cell. The genetic
material is dispersed in the cytoplasm. Bacteria are typical prokaryotic cells.
A prokaryotic cell has:
•On the outside, flagella and pili project from the cell's surface. These are structures
that (not present in all prokaryotes) facilitate movement and communication
•Inside the cell is the cytoplasm that contains the cell genome (DNA), ribosome and
•The cell wall is another typical structure of prokaryotic cell.