Any body, be it a plant or animal, is made up of millions of tiny structures known as cells. Cells are the tiniest part of a body, invisible to the naked eye and can be seen only with the help of a microscope. In a human body, there are approximately about 100 trillion or 1014 cells. There are two types of cells - eukaryotic cells and prokaryotic cells. The difference between these cells is that prokaryotic cells lack a cell nucleus, whereas, eukaryotic cells have a well-defined nucleus.
The nucleus was said to be discovered by a renowned Scottish botanist Robert Brown, who described this part observed in plant cells, through a microscope, as an opaque spot. This theory was later researched and developed by Antonie Philips van Leeuwenhoek, who is known as the father of microbiology. The word nucleus is taken from the Latin word nuculeus, which means 'center' or 'kernel'. If we observe the structure and functions of the nucleus we can see that it contains genetic material and is the largest organelle in the cell. The nucleus is covered by a nuclear membrane, which separates it from other organelles in the cell. This part is the most important component of a cell.
Functions of the Cell Nucleus
Biology is a branch of science which deals with the study of life. This is further divided into microbiology, which consists of the study of cells, their organelles and the functions. As seen earlier, it is the eukaryotic cells which have a prominent nucleus.
- All the cells in an eukaryotic organism have a single nucleus. But there are a few exceptions like the paramecium, a microscopic organism which has two nuclei (plural for nucleus) and some molds which have many nuclei. Interestingly, the human red blood cells do not have a nucleus.
- The nucleus is spherical in shape and is located in the cytoplasm of the cell. It is separated from the rest of the cell organelles with a nuclear envelope or nuclear membrane. This membrane protects the DNA and other genetic material present inside the nucleus.
- The nucleus size is measured in microns or micrometers and is approximately 1.7 µm.
- The main function of this cell organelle is storing the chromatins, which are strands of the DNA and which carry the genes. There are a total of 46 chromosomes in a cell. This cell organelle is also the site for protein synthesis, where the messenger RNA (mRNA) undergo transcription. This process is known as gene expression.
- Nucleus plays a vital role in the production of ribosomes, which synthesize proteins from amino acids. The ribosomes also convert genetic information obtained from RNA to proteins. These ribosomes are secreted by the nucleolus.
- The nucleus also acts as a storehouse for genetic information to be transferred, by the process of meiosis (where the number of chromosomes is divided into half), to the coming generations.
- The metabolism of nutrients and the release of energy in the cells takes place in the nucleus. The cell cycle is controlled by the nucleus and it also takes care of the wear and tear of the genetic material.
- There is a nuclear pore complex present in the nucleus which helps in transportation of the molecules of protein through the nuclear membrane.
This was all about the nucleus and its functions. Sometimes playing a role as 'the brain of the cell', the nucleus also assists in controlling actions like eating, movement, and reproduction.