Bacteria are amongst the simplest of organisms – they are made of single cells. Their cell structure is simpler than the cells of animals, plants and fungi.
Cells of bacteria do not have a nucleus. Their DNA is present in the cytoplasm of their cells. It is found in a loop. Bacteria can also have much smaller circles of DNA called plasmids. These are able to move from one cell to another. They provide genetic variation.
|Eukaryotic cell||Prokaryotic cell|
|Size||Most are 5 μm – 100 μm||Most are 0.2 μm – 2.0 μm|
|Outer layers of cell||Cell membrane - surrounded by cell wall in plants and fungi||Cell membrane - surrounded by cell wall|
|Cell contents||Cytoplasm, cell organelles include mitochondria, chloroplasts in plants, and ribosomes||Cytoplasm, ribosomes - no mitochondria or chloroplasts|
|Genetic material||DNA in a nucleus - plasmids are found in a few simple eukaryotic organisms||DNA is a single molecule, found free in the cytoplasm - additional DNA is found on one or more rings called plasmids|
|Type of cell division||Mitosis||Binary fission|
A group of organisms called Archaea are also prokaryotic.