Cell Nucleus Facts

The cell nucleus is a compact organelle found in every eukaryotic cell. In fact, its presence is used as a differentiating point between eukaryotes and prokaryotes. As the nucleus houses the primary components of a eukaryotic cell, you can imagine its importance in the overall functioning of the cell. Functionally, one of the interesting cell nucleus activities is its active participation in protein synthesis. Scroll down to learn more facts about cell nucleus.

Interesting Facts About Cell Nuclei

Cell nucleus is an organized organelle, which is responsible for major cellular activities of a eukaryotic organism. Even though majority of the eukaryotic cells have a single nucleus, there are some modifications. For example; a matured human red blood cell lacks nucleus (enucleate), a paramecium contain two nuclei and a smile mold contains millions of nucleus (multinucleate). Detailed cell nucleus information is presented below.

Discovery
In biology report, the cell nucleus was observed for the first time by Antonie Philips van Leeuwenhoek, the father of microbiology. But, the actual credit for discovery of cell nucleus goes to Robert Brown, a Scottish botanist. In his 1831 paper publication, he mentioned the presence of opaque spots in plant tissues. He assumed the spots as significant constituents of cells and termed them as nucleus.

Location
The cell nucleus is located in the middle of the cell, which is surrounded by the cytoplasm. However, this is not always true for all types of eukaryotic cells. In some, it is present towards the border of the cell. This is applicable in case of plant cells, in which a large vacuole is present in the near center of the cells. Also, during cell division, the location of cell nucleus deviates and holds an off-center position.

Size
It is the largest and most prominent organelle in a cell. The actual size of the cell nucleus varies from one organism to another. Also, the dimension of nucleus changes with respect to the particular stage in the cell cycle. On an average, the nucleus of a mammalian cell is about 6 micrometer.

Structure
Coming to cell nucleus structure, a double membrane separates it from the remaining parts of the cell. Structurally, this nuclear membrane maintains continuity with the membrane of rough endoplasmic reticulum. This is crucial for transportation of nuclear materials from inside to the outside during protein synthesis. The nuclear membrane is also responsible for maintaining a near circular shape of the nucleus.

Composition
The cell nucleus is made up of a double layered nuclear membrane, nucleolus (origin of ribosomes and RNA), chromatin (makes up chromosomes), chromosomes (hereditary material), nucleosome (made up of proteins and DNA) and histone proteins (bind DNA in a compact form). To be more precise, the cell nucleus contains a maximum amount of hereditary material for a cell.

Functions
The main functions of a cell nucleus are regulating cell metabolism, cell division, gene expression and also, controlling protein synthesis. Hence, it won't be wrong to say that the cell nucleus is functionally the most important organelle. It regulates all cellular activities, either directly or indirectly. It is for this reason why, the nucleus of a cell is considered as the 'brain' or 'control center' of a eukaryotic cell.

So, aren't these cell nucleus facts interesting to study? As far as synthesis of proteins is concerned, the transcription phase is carried out in the cell nucleus, while the later translation phase occurs outside the nucleus, in the cell cytoplasm. Other than the cell nucleus, some amount of the hereditary material is present in the mitochondrion organelle.