The nucleoid is a region of prokaryotic cells where the genetic material of these organisms is found. It is usually made up of a single circular DNA molecule.
Prokaryotic organisms , such as bacteria and cyanobacteria, are beings that do not have a defined nucleus and present the genetic material dispersed in the cytoplasm without any nuclear envelope. In these organisms, the presence of the so-called nucleoid occurs.
The nucleoid, also called the bacterial chromosome, is the region where the DNA of the prokaryotic organism is found . In the nucleoid, the DNA generally appears as a single circular double-stranded DNA molecule. Unlike DNA from eukaryotic cells, the presence of histone proteins, which are related to the process of DNA compaction and unpacking, is not observed.
The structure of the nucleoid is very variable and is directly related to the physiological state of the cell. In cells that are in the exponential phase of multiplication (phase in which the cells divide), for example, the DNA is very compacted, and in the stationary phase of multiplication (phase in which division is interrupted) the DNA is more chilled out.
Bacteria have a region of DNA known as the nucleoid.
The DNA present in the nucleoid has all the information that is necessary for the cell to survive. In addition, this DNA does not have introns , that is, parts of the DNA of a gene that are not responsible for encoding any part of the protein produced by the gene and has the ability to self-duplicate.
In prokaryotic organisms, there are also DNA molecules that are not attached to the bacterial chromosome , replicating independently. These molecules, called plasmids, are formed by small portions of double-stranded DNA that are presented in a circular fashion.
Plasmids have an average of 5 genes to 100 genes . These genes are not responsible for producing essential traits, however, they are related to some adaptive advantages. Among these advantages, we can mention antibiotic resistance and tolerance to toxic metals . It is important to note that plasmids can be acquired or even lost without causing damage to the cell.