The cell nucleus is called the center of eukaryotic cells, which contain all the genetic data necessary at the time of reproduction, the cell nucleus is composed of a soft organelle that is made up of DNA and RNA, these remain isolated and they are protected until the moment of fusion, in the case of animal reproduction, this organelle or organelle does not release its content until the sperm and ovum are fertilized. This is surrounded by a lipid layer rich in proteins that keep the cytoplasm at a distance, which serves as an inert gelatin in which all the other components of the cell are deposited.
The nuclear membrane or nuclear envelope is a kind of dividing wall that acts as a filter, it is important to emphasize that these membranes have a function of protection, regulation and care between the other organelles of the cell, the segregation or mixture of these could cause alterations drastic in the composition of matter. The membranous fiber is composed of ribosomes, which synthesize the protein cultures that exist between the nucleus and the cytoplasm. This ribosomal membrane has a fissure, small atomic pores through which the protein is fired and maintains a relationship with the outside of the nucleus, without emitting other forms of communication.
The nucleolus for its part, could be considered as the most important part of the whole cell, since it is represented as the power center of the cell, all the ribosomal contents to be developed are housed in the nucleolus, it sends this protection in the form of filter to the nucleus membrane and also has the capacity of DNA, all its structure and shape, it should be noted that this nucleolus is found in an area of the cell nucleus devoid of a membrane that protects it, however, it is "swimming" in a more liquid viscous substance called nucleoplasm, composed of 85% water and the rest of glucosal and protein solutes.
At the end of this explanation, we note the reason why the eukaryotic cell elaborates all this mechanism, the chromosome, if its genome is correct, and the chromosome is in the correct quantities, it will be the precursor of the genetics and sexual affinity of the organism that is reproducing.