DNA in Prokaryotes
- The DNA in prokaryotic cells is significantly different from the DNA found in eukaryotic cells
- “Prokaryote” means “before the nucleus”
- The DNA is double-stranded
- Prokaryotes possess a single, circular chromosomal DNA molecule
- It is sometimes referred to as a nucleoid
- They also usually have one or more plasmids
- Plasmids are very small circular DNA molecules
- They usually only contain a few genes
- Plasmids are more accessible for proteins required for gene expression and therefore contain genes that are required often, quickly and/or in emergencies
- The genes for antibiotic resistance are often found in plasmids
- The DNA within prokaryotic cells is not associated with any proteins
- Eukaryotic DNA associates with histone proteins
Image showing the arrangement of DNA within a prokaryotic cell