Eukaryotic or eukaryotic It is an adjective that is used in the biology to refer to cells that have a differentiated nucleus, protected by a membrane and with organized cytoplasm. The organism constituted by this type of cell is also known as eukaryotic.
Eukaryotic cells have their genetic information enclosed within the nuclear envelope . Its cytoplasm has interconnected organelles whose limits are fixed by biological membranes. The most notorious compartment of the protoplasm is the nucleus .
Eukaryotes usually contain mitochondria , which are membranous organelles that produce Energy . Some eukaryotic protists, however, no longer exhibit mitochondria after the course of evolution. The presence of plastids in the cytoplasm, on the other hand, allows certain eukaryotes to perform the photosynthesis .
Despite the variety of eukaryotes, you are cells they share the same biochemical composition and a homogeneous metabolism, a fact that represents an important difference with respect to prokaryotes , the cells whose genetic material is distributed in various organelles.
It should be noted that organisms eukaryotes constitute the domain Eukarya , which includes beings from the four kingdoms: animals, plants, fungi and protists. Most of the already extinct specimens, studied by paleontologists, belonged to this domain.
Regarding their reproduction, eukaryotes are able to divide in an asexual way (phenomenon known as mitosis), although in general they cross processes Reproductive sex that are based on meiosis and that is not seen in prokaryotic cells. To reproduce, eukaryotes alternate haploid generations, where only one specimen of each chromosome is found, and diploids, which have twice as many.
To pass from the first to the second type of generation it is necessary to go through nuclear fusion, or fertilization, and return to the first through meiosis. This does not mean, on the other hand, that there are no important differences between eukaryotes. It is worth mentioning that, compared to prokaryotes, their metabolism rates are lower and the time they need for generation is longer, and their surface area is not as representative of their volume.
Continuing with the reproductive process, it should be mentioned that it can take place in three distinct ways:
* bipartition: Consists of the division of a cell in two others that are absolutely equal;
* the budding: when a kind of tumor is formed in a cell, which grows for a while until it becomes an independent cell;
* sporulation: A cell begins by dividing its own nucleus into smaller copies, and finally does the same with its cytoplasm, so that more cells form.
The eukaryotic flagella
In the eukaryotic cells are one or two copies of one structure known as scourge. It is possible to distinguish two patterns of relationship between cells and their scourges: acroconts move behind their or their scourges, while opistoconts do so behind. The latter occurs in the kingdom of fungi and that of animals, and it is possible to notice such behavior in a sperm of our species.
The eukaryotic flagella belong to a group of structures known as undulipodios, where the cilia are also counted. A basic difference between the two is that the flagella are larger, since they are complicated by other structures added. Basically, both flagella and cilia present a cylindrical and even appearance throughout its entire body and with its rounded ends. Its core, which has a structure called anoxema, is covered by a tissue plasma, which allows the cytoplasm of the cell to penetrate and access inside.