Principles of Biochemistry

1.1.3.3 Nucleus

The nucleus is a membrane-enclosed organelle found in eukaryotic cells. It contains most of the cell's genetic material, organized as multiple long linear DNA molecules in complex with a large variety of proteins, such as histones, to form chromosomes. DNA directs the protein biosynthesis inside the cell.

 

The main structures making up the nucleus are the Nuclear membrane, a double membrane that encloses the entire organelle. Many nuclear pores are inserted in the nuclearmembrane, which facilitate and regulate the exchange of materials (proteins, tRNA, mRNA and rRNA) between the nucleus and the cytoplasm.

Chromatin is the combination of DNA and proteins. It is found inside the nuclei of eukaryotic cells.

Nucleolus is an organelle within the nucleus from where ribosomal RNA is produced. Some cells have more than one nucleus.