Chromosomes in prokaryotes

Chromosomes in prokaryotes: Prokaryotes (eg. Bacteria) typically have a single circular chromosome, but many variations do exist. Bacterial DNA also exists as plasmids, essentially miniature chromosomes, which are small circular pieces of DNA that are readily transmitted between bacteria. The distinction between plasmids and chromosomes is poorly defined, though size and necessity are generally taken into account.
Structure in sequences: Prokaryotes chromosomes have less sequence based structure than eukaryotes. They do, however, typically have a single point, the origin of replication, from which replication starts.
The genes in prokaryotes are often organised in operons, and do not contain introns, unlike eukaryotes.
Location in the cell: Bacterial chromosomes tend to be tethered to the plasma membrane of the bacteria. In molecular biology application, this allows for its isolation from plasmid DNA by centrifugation of lysed bacteria and pelleting of the membranes (and the attached DNA).
DNA packaging: Prokaryotes do not possess histones or nuclei, and so do not possess chromatin like eukaryotes. There is, however, thought to be some structural organisation to help condense the large molecule into the small prokaryotic cell.
Prokaryotic chromosomes and plasmids are, like eukaryotic DNA, generally supercoiled. The DNA must first be released into its relaxed state for access for transcription, regulation, and replication.