what is nucleolus and what is features of nucleolus?
Answers
Answer:
Nucleolus is a round and granular structure located inside the nucleus. It is the most prominent subnuclear structure in the nucleus. It is composed of proteins, DNA, and RNA.
The nucleolus is the distinct structure present in the nucleus of eukaryotic cells. Primarily, it participates in assembling the ribosomes, alteration of transfer RNA and sensing cellular stress. The nucleolus is composed of RNA and proteins, which form around specific chromosomal regions.
Structure of the Nucleolus
In eukaryotic cells, nucleolus has a well-ordered structure with four main ultrastructural components. The components can be further identified as:
Fibrillar Centers: It is the place where the ribosomal proteins are formed.
Granular Components: Before ribosomes are formed, these components have rRNA that binds to ribosomal proteins.
Dense Fibrillar Components: It has new transcribed RNA, which connects to the ribosomal proteins.
Nucleolar vacuoles: It is present only in plant cells.
The ultrastructure of the nucleolus can be easily visualized through an electron microscope. The arrangement of the nucleolus within the cell can be clearly studied by the techniques – fluorescent recovery after photobleaching and fluorescent protein tagging.
The nucleolus of several plant species has very high concentrations of iron in contrast to the human and animal cell nucleolus.
Nucleolus Function
The nucleolus is considered as the brain of the nucleus, covering nearly 25% volume of the nucleus. Primarily, it takes part in the production of subunits that unites to form ribosomes. Hence, nucleolus plays an important role in the synthesis of proteins and in the production of ribosomes in eukaryotic cells.