Bacteria are prokaryotes, meaning that they have no nucleus to contain their genetic material. In contrast to eukaryotic cells, which have a nucleus and membrane-bound organelles, bacterially-derived organisms have a single cell wall around the cytoplasmic fluid. The cell wall is made of peptidoglycan and lipopolysaccharides.
Bacteria have some general properties:
- They multiply rapidly in nutrient-rich environments.
- They can be found in very small numbers on solid surfaces or in water (although they tend to accumulate as aggregates).
- They reproduce by binary fission and can often be detected only through genetic analysis of their DNA.
- They have a cell wall made of peptidoglycan and lipopolysaccharides.
- Bacteria are usually classified by their shape: cocci, bacilli, spirilla and many others.