Eukaryotes are the most advanced organisms. In our article, we will consider which of the representatives of wildlife belong to this group and what features of the organization allowed them to occupy a dominant position in the organic world.
Who are eukaryotes
According to the definition of the concept, eukaryotes are organisms whose cells contain a formed nucleus. These include the following kingdoms: Plants, Animals, Mushrooms. And it doesn't matter how complex their body is. A microscopic amoeba, a volvox colony, a giant sequoia are all eukaryotes.
Although true tissue cells can sometimes lack a nucleus. For example, it is not present in erythrocytes. Instead, this blood cell contains hemoglobin, which carries oxygen and carbon dioxide. Such cells contain a nucleus only at the first stages of their development. Then this organelle is destroyed, and at the same time the ability of the entire structure to divide is lost. Therefore, having performed their functions, such cells die.
Structure of eukaryotes
All eukaryotic cells have a nucleus. And sometimes not evenone. This two-membrane organelle contains in its matrix genetic information encrypted in the form of DNA molecules. The nucleus consists of a surface apparatus that provides the transport of substances, and a matrix - its internal environment. The main function of this structure is the storage of hereditary information and its transfer to daughter cells formed as a result of division.
The internal environment of the kernel is represented by several components. First of all, it is karyoplasm. It contains the nucleoli and chromatin strands. The latter are composed of proteins and nucleic acids. It is during their spiralization that chromosomes are formed. They are directly carriers of genetic information. Eukaryotes are organisms in which, in some cases, two types of nuclei can form: vegetative and generative. A striking example of this is infusoria. Its generative nuclei carry out the preservation and transmission of the genotype, and the vegetative nuclei regulate protein biosynthesis.
Main differences between pro- and eukaryotes
Prokaryotes do not have a formed nucleus. This group of organisms includes the only kingdom of living nature - Bacteria. But such a feature of the structure does not mean at all that there are no carriers of genetic information in the cells of these organisms. Bacteria contain circular DNA molecules - plasmids. However, they are located in the form of clusters in a certain place in the cytoplasm and do not have a common shell. This structure is called a nucleoid. There is one more difference. DNA in prokaryotic cells is not associated with nuclear proteins. Scientists have established the existenceplasmids and in eukaryotic cells. They are found in some semi-autonomous organelles such as plastids and mitochondria.
Progressive body features
Eukaryotes are organisms that differ in more complex structural features at all levels of organization. First of all, this concerns the method of reproduction. The bacterial nucleoid provides the simplest of them - cell division in two. Eukaryotes are organisms that are capable of all types of reproduction of their own kind: sexual and asexual, parthenogenesis, conjugation. This ensures the exchange of genetic information, the appearance and fixation of a number of useful traits in the genotype, and hence the best adaptation of organisms to constantly changing environmental conditions. This feature allowed eukaryotes to occupy a dominant position in the system of the organic world.
So, eukaryotes are organisms whose cells have a formed nucleus. These include plants, animals and fungi. The presence of a nucleus is a progressive feature of the structure, providing a high level of development and adaptation.
