We explain what the cell nucleus is and the main functions of this organelle. In addition, how each of its parts are composed.
What is the cell nucleus?
The cell nucleus is a membranous organelle found inside the cells. eukaryotic cells exclusively, and that it contains most of the genetic material of the cell, organized in macromolecules from DNA (called "chromosomes"), Inside which, in certain positions called" locus ", are the genes.
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 in the synthesis of protein, since DNA contains the necessary pattern for all the operations of the cell.
Interestingly, the cell nucleus was the first of the cellular organelles to be discovered through the observation through microscope. The first to take note of it was Anton van Leeuwenhoek (1632-1723), in Salmon Cells.
But the true function of the nucleus and its importance in inheritance and the cell reproduction became apparent much later, thanks to Mendel's laws and the discovery of the mitosis cell phone in the early twentieth century.
The cell nucleus is one of the fundamental organelles of the cell, essential to reach high levels of complexity of life, as we are multicellular beings. In fact, in its presence or absence within the cytoplasm cell is based on the distinction between prokaryotic cells (more primitive) and eukaryotes (more evolved).
Functions of the cell nucleus
The core functions are:
- Contain and store the chromosomes that carry genetic information (genes), especially during reproductive processes such as mitosis.
- Organize genes on specific chromosomes, which allows cell division and facilitates the work of transcription of their content.
- Allow the transport of molecules between the nucleus and the cytoplasm, selectively according to the size of the cells.
- Transcribe the RNA messenger (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.
- Produce ribosomes essential to create Ribosomal RNA (rRNA).
Parts of the 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. This membrane of the nucleus is known as nuclear envelope or karyotheque and has a series of pores that allow bidirectional movement between nucleus and 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.
In the animal cells There is also a nuclear lamina that provides support to the nucleus and allows the organization of chromosomes. This lamina consists of two fibrous 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 karyosomal association, the promyelocytic leukemia bodies, and the speckles.