Cell Nucleus – Concept, functions and structure

We explain what the cell nucleus is and the main functions of this organelle. In addition, how each of its parts are composed.

Cell nucleus
The cell nucleus preserves genetic material and makes it work when needed.

What is the cell nucleus?

It is known as the cell nucleus a membranous organelle found inside eukaryotic cells exclusively, and that contains most of the genetic material of the cell, organized in DNA macromolecules called chromosomes, within which genes are found.

The cell nucleus operates as a cell control tower, since its primary mission is to preserve genetic material and put it into operation when necessary, such as in cell division or protein synthesis, since DNA contains the necessary pattern for all cell operations.

Interestingly, the cell nucleus was the first of the cellular organelles to be discovered through microscopic observation. The first to take notice of him was Anton van Leeuwenhoek (1632-1723), in salmon cells.

But the true function of the nucleus and its importance in cellular inheritance and reproduction would become apparent much later, thanks to Mendel’s laws and the discovery of cell mitosis in the early 20th century.

The cell nucleus it is one of the fundamental organelles of the cell, indispensable to reach high levels of complexity of life, as we are multicellular beings. In fact, in its presence within the cell cytoplasm, prokaryotic cells (more primitive) and eukaryotic cells (more evolved) are distinguished.

Functions of the cell nucleus

Cell nucleus
The nucleus produces ribosomes essential to create Ribosomal RNA.

The core functions are:

  • Contain and store the chromosomes that carry genetic information (genes), especially during reproductive processes such as mitosis.
  • It organizes genes on specific chromosomes, which allows cell division and facilitates the work of transcribing their content.
  • It allows the transport of molecules between the nucleus and the cytoplasm, selectively according to their size.
  • It produces messenger RNA (mRNA) from the DNA matrix, which transports the genetic sequence to the cytoplasm and serves as a matrix for the synthesis of proteins that takes place within the cell.
  • It produces ribosomes essential to create Ribosomal RNA (rRNA).

Parts of the cell nucleus

Cell nucleus
The cell nucleus is covered by a membrane called nuclear envelope.

The cell nucleus is covered by a membrane similar to the plasma membrane of the cell, which delimits its body and separates it from the outside. Said core membrane is known as nuclear envelope and it has a series of pores that allow bidirectional movement between the nucleus and the cytoplasm.

Another important component of the nucleus is the nucleolus, a region of the nucleus abundant in chromatin and genetic material, which plays fundamental roles in cell division and in the biosynthesis of ribosomes, necessary for RNA.

There is also, in animal cells, a nuclear lamina that provides the nucleus with support and allows the organization of chromosomes. This lamina consists of two networks of intermediate filaments composed of proteins, which are composed in the cell cytoplasm and then enter the nucleus.

Finally, there are subdomains of the nucleus of which little is known, that is, specialized compartments that are linked to various functions of the nucleus in ways that are still completely misunderstood. These are the Cajal Bodies, the Interphase Polymorphic Cariosomic Association, the Priomyelocytic Leukemia Bodies and the “speckles” (from the English “dots”).