The nucleolus in eukaryotic cells is best compared to a factory that produces tools that are used to construct other resources. The nucleolus’ fundamental purpose is to assemble and create ribosomes. Ribosomes’ principal purpose is to produce proteins required by the cell.
Consider the following analogy: a civilisation does not require hammers, saws, or wrenches. Human communities, on the other hand, demand finished commodities such as houses and automobiles. Similarly, cells don’t want ribosomes; they want the proteins that ribosomes make. A single tool, in the tool factory analogy, can be used to make a variety of things. Similarly, the nucleolus of the cell creates ribosomes, which have a similar shape but may produce a wide range of proteins.
In an organism’s cells, ribosomes are abundant, and the nucleolus creates a vast number of them to supply the cell’s protein needs. While majority of the ribosomes in a cell are found in the endoplasmic reticulum, others are free to float around in the cytoplasm. Ribosomes occasionally clump together with other ribosomes. In the growing, functioning cells of some animals, there are up to 10 million ribosomes. The nucleolus must double this number each time the cell divides.