Structure

• Nuclear content
  • Chromatin: complex of DNA, histones, and nonhistone proteins
  • Nucleolus: site of rRNA synthesis and ribosomal subunit assembly

Functions

• Storage of the entire genetic information of an organism in the form of chromatin (except mitochondrial DNA)
• Duplication of genetic information before cell division (DNA replication): See the cell cycle for further information.
• Transcription: initial step of protein synthesis
• Synthesis of rRNA in the nucleolus
• Packaging and protection of inactive DNA by histones