The name of eukaryotic cell is one that is applied to all cells of a living organism that have a membrane that covers them and protects them from the outside environment, but especially because they have a defined cell nucleus and also delimited within the cell by a protective layer or nuclear membrane. Eukaryotic cells differ from other types of cells such as prokaryotic cells in which the nucleus also exists but, as it is not covered by any membrane or envelope, it is dispersed throughout the cell.
Eukaryotic cells are present in most of the living beings on the planet since their composition allows us to speak from tiny beings to the most gigantic mammals and animals in the world. All of them have this type of cells. On the contrary, prokaryotic cells are only present in organisms known as bacteria and archaea, much simpler although they reproduce very easily. For specialists, the distinction millions of years ago between prokaryotic and eukaryotic cells was one of the reasons why life became more complex and advanced.
Inside the eukaryotic cell we find the cytoplasm, which is an emulsified liquid in which the different parts of the cell take place, including the nucleus. The cytoplasm is something like the placenta of a pregnant woman since without it the different elements of a cell could not survive. The plasma membrane will be the one that covers the whole of the cytoplasm and the other elements of a cell, protecting them and separating them from the external environment. In the cytoplasm we find the cell nucleus that is in turn covered by a membrane or nuclear envelope, which protects it and differentiates it from the rest of the parts of the cell.
The nucleus is the most important part of a cell since it houses the genetic material or information that will make the living being whatever it is and nothing else. This information is reproduced in the same way in all the cells of the living being and will determine it from the moment of its birth until its death.