Nucleoid is the region of the bacterial cell which lacks a limiting membrane and contains the bacterial chromosome. BacteriaI circular dsDNA molecule is associated with polyamines instead of histone proteins.

Nucleoid associated proteins are of four types which facilitates compaction of chromosomal DNA by bending, bridging, and wrapping i.e. HU is heat unstable protein, H-NS is histone-like nucleoid structuring, IHF stands for integration host factor, and SMC is structural maintenance protein.

H-NS protein helps in condensation of DNA by first binding with the DNA and then these proteins bind with each other and form an aggregate of four or more H-NS units.

Archaebacteria is a group of prokaryotes which resembles eukaryotes in some aspect and differs from the bacterial group. Archaeans uses eukaryotes like histones to condense their DNA molecules.

Plasmids are extrachromosomal, autonomous, and self-replicating DNA molecule that maintains discrete genetic element in bacteria. Most plasmids are negatively supercoiled, circular dsDNA molecules but linear plasmids have also been reported.