Nucleus
- Nuclear envelope with pores (double-membrane)
- Site of DNA replication and RNA synthesis (transcription)
- Contains: chromatin, nucleolus (rRNA and ribosomal proteins)
- * The nuclear envelope is a discontinuous double-membrane.
- The gaps in the envelope are called nuclear pores.
- The nucleus lies within the nuclear envelope
- It is the largest organelle in eukaryotic cells (approximately five micrometers in diameter and visible under a light microscope).
- The nucleus is the site of DNA replication and RNA synthesis (transcription).
- Chromatin, the uncondensed form of DNA, resides in the nucleus
- A nucleolus – nuclei can contain one or more of these nonmembranous organelles; cells that produce a large amount of proteins have a proportionally large nucleolus (and a large number of ribosomes).
- rRNA resides within the nucleolus where it is synthesized; ribosomal proteins assemble in the nucleolus before maturing in the cytoplasm.