Hello friends, in today’s article we will study about nucleolus. Like – what is nucleolus? What is the function of nucleolus? Where is nucleolus found? Today we will know the answers to many such questions, so without wasting time let’s start.
What is the nucleolus?
Nucleolus is found inside nucleus, and its synthesis of ribosomal RNA. Usually, the nucleus of a diploid cell has two nuclei and the gamete has only one. The size of the nucleolus is related to the synthetic activities of the cell. Nucleoli are larger in cells that are actively engaged in protein synthesis.
What is the structure of nucleolus? –
The nucleolus consists of the following parts:
- Pars amorpha or amorphous matrix.
- The fibrillar zone is made up of fibrils of rRNA and ribonucleoprotein.
- The granular region contains ribonucleoprotein (RNP) particles. These are the precursors of ribosomes.
- Perinucleolar chromatin is made up of chromatin granules. The different regions of the nucleus are related as follows:
Nuclear DNA → Fibrillar zone → Granular zone → Cytoplasmic ribosomes
The nucleolus is mainly composed of RNA and proteins. Proteins are exclusively phosphoproteins, and RNA is similar to ribosomal RNA. A ring of DNA has also been found, representing hetero chromatin regions of the chromosomes associated with the nucleolus. In addition, enzymes such as acid phosphatase, nucleoside phosphorylate and DPN synthesis enzymes are found.
What is the function of nucleolus?
RNA synthesis –
Ribosomal RNA (rRNA) is synthesized inside the nucleolus. Chromatin associated with the nucleolus contains ribosomal genes or rRNA that code for ribosomal RNA. Ribosomal RNA is synthesized as 28S and 18S RNA present in the large and small subunits of ribosomes of eukaryotic cells.
Biogenesis of ribosomes – Two types of rRNA synthesized in the nucleolus are attached to proteins that are transferred from the cytoplasm to the nucleolus. Ribonucleoprotein molecules represent precursors of ribosomal units and are observed as granules in the nucleolus. These precursors move from the nucleolus to the cytoplasm and combine to form ribosomes.
Chromatin → Filaments→ Granules → Ribosomes
Frequently Asked Questions –
Where is nucleolus found?
Nucleolus is found inside the nucleus present in the eukaryotic cell.
Which organelle contains nucleolus?
Nucleolus is present in the nucleus.
What does the nucleolus do in the cell?
The nucleolus synthesizes ribosomal RNA in the cell.
What does the nucleolus do in an animal cell?
In animal cells, the nucleolus synthesizes and assembles ribosomal RNA.
What does the nucleolus do in a plant cell?
The plant cell and the animal cell have the same type of nucleolus and perform the same function in both cells, to synthesize and assemble ribosomal RNA.
Give reason why nucleolus is small in muscle cell but large in liver cell.
Muscle cells are not active in protein synthesis, but liver cells are actively involved in protein synthesis.
What is the main function of nucleolus?
The main function of the nucleolus is the biogenesis of ribosomes.
By whom was the nucleolus described?
The nucleolus was described by Fontana.
So friends, in today’s article we have studied What is the function of nucleolus. Friends, if you did not like this article, then please comment and tell your suggestions and our mistakes.