Characteristics of Prokaryotic Cells
There are two types of cells on the basis of nucleus present within the cell.
1. Prokaryotic cell
2. Eukaryotic cell
1. Characteristics of Prokaryotic cell
- Prokaryotic cell type is called prokaryotes.
- Prokaryotic cell lacks membrane-bound organelles.
- The size range of prokaryotic cell is usually smaller than 3 micrometre.
- The genetic material of the prokaryotic cell is located in nuclear region or nucleoid.
- Nucleoid contains a single chromosome and a piece of circular double-stranded DNA.
- Further prokaryotic cells are divided into two types on basis of composition of cell wall into gram positive and gram negative cell.
- Here nuclear membrane, nucleolus, histone proteins are absent.
- Genes may be present in the cluster.
- Plasma membrane lacks sterols.
- The ribosome is of 70 S structure and evenly dispersed in the cytoplasm.
- Chloroplast, Golgi body, Mitochondria, Pinacocytes and endoplasmic reticulum is absent.
- Mesosomes and gas vacuole may be present in some prokaryotes.
- The cell wall of the prokaryotic cell is mainly composed of peptidoglycan, polysaccharides and glycoprotein molecules.
- It may show the presence of endospore in some prokaryotes.
- The respiratory system is located in the plasma membrane.
- The lysosome is absent in prokaryotes.
- It shows a wide variety of anaerobic energy-yielding mechanism.
- A prokaryotic cell has the ability to fix atmospheric nitrogen.
- It shows the presence of magnetosome.
- The G+C content is around 28 to 70 %
- Protein synthesis is carried out in the cytoplasm.
- It may contain flagella, pili and capsule on its surface.
- A chromosome is circular in shape.
- Mitosis and Meiosis mechanism is absent in a prokaryotic cell.
- Reproduction of prokaryotic cell is carried out binary fission mechanism.
- Magnetogenesis is absent in these cells.
- Examples of prokaryotic cells are Bacteria, Cyanobacteria, Eubacteria, and Archaebacteria.