Question

Is nucleolus covered by membrane?

Answer 1

Hint:- The nucleolus, occupying almost 25 percent of the volume of the nucleus, is considered the brain of the nucleus. It is mainly involved in the manufacture of subunits that join to form ribosomes. The nucleolus therefore plays an important role in protein synthesis and the development of ribosomes in eukaryotic cells.

Complete Answer:- The nucleolus is an organelle that lacks a membrane and it is present inside the nucleus of the cell. The nucleolus in the nucleus of eukaryotic cells is the distinct structure present. It primarily involves assembling of ribosomes, modifying RNA transfer and sensing cellular stress. RNA and proteins that form around particular chromosomal regions are composed of the nucleolus. It is one of the nucleus's primary components. The structural components form the chain of RNA and DNA along with other components. Deoxyribonucleic acid (DNA), ribonucleic acid (RNA) and proteins are the major constituents of the nucleolus.
In eukaryotic cells, with four major ultrastructural elements, the nucleolus has a well-ordered structure. It is possible to further classify the components as:
Fibrillar Centres: The position where the proteins of the ribosomes are produced.
Granular Components: These parts have rRNA binding to ribosomal proteins before ribosomes are developed.
Dense Fibrillar Components: Newly transcribed RNA that binds to the proteins of the ribosomes.
Nucleolar vacuoles: They are present in plant cells exclusively.

Note:- Through an electron microscope, the nucleolus morphology can be easily visualised. With the methods of fluorescence, recovery after photo-bleaching and fluorescent protein labelling, the structure of the nucleolus inside the cell can be clearly examined. In comparison to the human and animal cell nucleolus, the nucleolus has very high amounts of iron in many plant species.