The nucleus is a membrane-bound organelle that contains genetic material (DNA) of eukaryotic organisms. As such, it serves to maintain the integrity of the cell by facilitating transcription and replication processes.
It's the largest organelle inside the cell taking up about a tenth of the entire cell volume. This makes it one of the easiest organelles to identify under the microscope.
Some of the other main components of a nucleus include:
- Phospholipid bilayer membrane
* Some eukaryotic cells lack a nucleus and are referred to as enucleate cells (e.g. erythrocytes) while others may have more than one nucleus (e.g. slime molds).