Eukaryotes are organisms whose cells have a nucleus

Eukaryotes are the most progressively organized organisms. In this article, we will consider who among the representatives of wildlife belongs to this group and what features of the organization have allowed them to occupy a dominant position in the organic world.

Who are the eukaryotes?

According to the definition of the concept, eukaryotes are organisms, the cells of which contain the formed nucleus. These include the following kingdoms: Plants, Animals, Mushrooms. And it does not matter how complex their body is. Microscopic amoeba, colonies of volvox, giant sequoia - all of them are eukaryotes.

Although cells of these tissues can sometimes be devoid of nuclei. For example, it does not exist in red blood cells. Instead, this blood cell contains hemoglobin, which carries oxygen and carbon dioxide. Such cells contain the nucleus only at the first stages of their development. Then this organelle collapses, and with it the ability of the entire structure to divide is lost. Therefore, after fulfilling their functions, such cells die.

Structure of eukaryotes

In the cells of all eukaryotes there is a nucleus. And sometimes not even one. This bi-membrane organelle contains genetic information encoded in the form of DNA molecules in its matrix. The core consists of a surface device that provides transport of substances, and a matrix - its internal environment. The main function of this structure is the storage of hereditary information and its transmission to daughter cells formed as a result of division.

The inner core environment is represented by several components. First of all, it is a karyoplasm. It contains nucleoli and chromatin filaments. The latter consist of proteins and nucleic acids. It is during their spiral formation that chromosomes are formed. They are directly carriers of genetic information. Eukaryotes are organisms in which in some cases nuclei of two types can be formed: vegetative and generative. A vivid example of this is the infusoria. Its generative nuclei carry out the preservation and transfer of the genotype, while the vegetative nuclei regulate the biosynthesis of the protein.

The main differences between pro- and eukaryotes

Prokaryotes do not have a formed nucleus. To this group of organisms belongs the only realm of living nature - Bacteria. But such a feature of the structure does not at all mean that there are no carriers of genetic information in the cells of these organisms. Bacteria contain circular DNA-plasmid molecules. However, they are located in the form of clusters in a certain place of the cytoplasm and do not have a common envelope. Such a structure is called a nucleoid. There is one more difference. DNA in prokaryotic cells is not associated with the proteins of the nucleus. Scientists have established the existence of plasmids in eukaryotic cells. They are found in some semi-autonomous organelles, for example, in plastids and mitochondria.

Progressive features of the structure

Eukaryotes include organisms that are more complex in structure at all levels of the organization. First of all, it concerns the method of reproduction. Nucleoid bacteria provide the simplest of them - dividing the cells in half. Eukaryotes are organisms that are capable of all kinds of reproducing themselves: sexual and asexual, parthenogenesis, conjugation. This ensures the exchange of genetic information, the emergence and consolidation in the genotype of a number of useful traits, and hence, better adaptation of organisms to the constantly changing environmental conditions. This feature allowed the eukaryotes to occupy a dominant position in the system of the organic world.

So, eukaryotes are organisms, in the cells of which there is a formed nucleus. These include plants, animals and mushrooms. The presence of the core is a progressive feature of the structure, which ensures a high level of development and adaptation.