Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025
Definition
The nucleoid is the irregularly-shaped region within a prokaryotic cell that contains most of the genetic material. Unlike a eukaryotic nucleus, it is not surrounded by a nuclear membrane.
5 Must Know Facts For Your Next Test
The nucleoid contains the cell's chromosome, usually a single circular DNA molecule.
It is not enclosed by a membrane, distinguishing it from the nucleus in eukaryotic cells.
Proteins associated with DNA within the nucleoid help in processes like replication and transcription.
The nucleoid can occupy up to half of the cell's volume depending on its stage in the life cycle.
Supercoiling helps compact the DNA within the nucleoid for efficient space utilization.