And we'll discuss that when we discuss replication, translation as well as transcription. Now, let's move on to a region of the nucleus known as the nucleolus. So at the heart of any nucleus of any eukaryotic cell is a region known as the nucleolus. And it takes up about 25% of space found inside that nucleus. Now, this is a very important section because within this section we have RNA molecules and proteins that are responsible for synthesizing our RNA or ribosomal RNA that is needed to create ribosomes found within the endoplasmic reticulum as well as inside our cytosol of the cell. Finally, let's discuss the composition of DNA inside the nucleus.