The nucleus controls all the biological activities of the cell. That is why it is called the ‘control room’ of the cell. The nucleus was first described by Robert Brown (1831). Normally a cell has a nucleus. Some cells such as RBCs do not have a nucleus. These are called enucleated. Multinucleated cells are called coenocytes.
The nucleus has four parts:
1. nucleus cover,
3. Chromatin threads and
4. The nucleus.
1. Centroid casing (Nuclear Envelope) – It consists of two membranes around the nucleus. It has small nuclear pores at places. The nuclear envelope nucleus and cytoplasm, nucleus regulates the exchange of substances between the liquid.
2. Nucleoplasm – The nucleus is filled with transparent, semi-liquid and particulate matter. It Kromonimeta or live chromatin fibers and Centdraikaaa (Nukliolai).
3. nucleus reticulum – Dhagenuma chromatin make fibers nucleus reticulum. These fibers are called chromonemata and the net formed by them is called nuclear reticulum or nucleo-reticulum or chromatin mesh-nucleus. Cell division at the time of chromatin network condenses clearly Tnhuon or rods. These structures are called chromosomes. Chromosomes are visible only at the time of nuclear division.
Nucleus reticulum is composed of Nuklioprotin (nucleic acids and proteins). Two types of nucleic acids are found in the nucleus:
1. Deoxyribonucleic acid- DNA
2. Ribonucleic Acid- RNA
Of these, DNA is found only in chromosomes and RNA is found in both nucleus and cytoplasm.
4. Nucleolus – Inside the nucleus there are one or two nuclei which contain RNA and proteins. There is a synthesis of ribosomal RNA to make Ribosomes.
Functions of Nucleus
1. The nucleus controls all the biological activities that take place inside the cell. That is why the nucleus is called the control room of the cell.
2. The genetic material is found in the nucleus . Responsible for inheritance of traits of an organism
3. It is responsible for cell division, which leads to an increase in the number of cells and in the body of organisms.
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