Bacteria (singular-bacterium) are prokaryotes, and have a simple cell structure consisting of:
- Cytoplasm containing the bacterial chromosome, ribosomes, stored energy inclusions, and often plasmids.
- Cytoplasmic membrane and mesosomes
- Cell wall (except bacteria with deficient cell walls such as Mycoplasma)
- External structures such as capsule, fimbriae (pili), and flagella, depending on the species.
- Some bacteria such as Bacillus and Clostridium also produce endospores in unfavorable environmental conditions.