Prokaryotic and Eukaryotic Cells

There are two basic types of cells found in living organisms - the prokaryotic cells and the eukaryotic cells. This classification is based on three main features, namely;

• Organisation of biomembranes

• Nature of cytoplasmic organelles and

• Arrangement of the nuclear material

The prokaryotic cells do not have an organised nucleus. The genetic material (DNA) is found in a diffused state in the cytoplasm. It does not form a chromatin and it is not bound by a nuclear membrane. Membrane bound cell organelles are absent and the cell is bound by a single or unit membrane.

The prokaryotic types of cells are found only in primitive forms of life such as Cyanobacteria (or bluegreen algae) and bacteria.

fig. 12.10 - Prokaryotic and Eukaryotic Cells

The eukaryotic cells have an organised nucleus. The genetic material is found forming a distinct thread like chromatin. It is bound by a distinct nuclear membrane that separates it from the surrounding cytoplasm. Membrane bound cell-organelles are present. The cell is bound by a double membrane.

The eukaryotic type of cells are found in all other forms of life - algae, fungi, protozoan, higher plants and higher animals.