We explain what a eukaryotic cell is, the types that exist and their functions. In addition, its parts and differences with a prokaryotic cell.
What is a eukaryotic cell?
It is called the eukaryotic cell (from the Greek word Eukaryota, union of EU - true y karyon new, nucleus ) a all those in whose the cytoplasms can be found a well-defined cell nucleus whose interior contains the material genetic (DNA and RNA) of the organism. This distinguishes from prokaryotic cells, much more primitive and whose genetic material is dispersed in the cytoplasm.
The appearance of eukaryotic cells was an important step in the evolution of life, as it laid the foundations for a much greater biological diversity, including the possibility of cells specified within multicellular organizations, giving rise to the higher realms: animals, plants, fungi and protists. Living beings formed by eukaryotic cells are called eukaryotes.
However, the explanation of the emergence of eukaryotic cells is not very clear. The most accepted theory today raises the possible symbiogenesis between two prokaryotes, that is, a process of symbiosis between a bacterium and an arch that, cohabiting very closely, would end up composing the same organism with the passing of generations, of so dependent that they made each other.
Eukaryotic cell types
There are several types of eukaryotic cells, but fundamentally three are recognized, each with different structures and processes:
- Vegetable cells With a cellulose cell wall and proteins that cover their membrane and make them rigid, resistant, they have chloroplasts carrying the chlorophyll necessary to make photosynthesis.
- Animal cells . Without plates or cell walls, they have centrioles and vacuoles of smaller size, although more abundant.
- Fungal cells . Although they have a cell wall similar to the plant, it is made of chitin, and therefore have a lower cellular definition. They can be considered an intermediate step between animal and plant, because they do not do photosynthesis.
It can serve you: Plant Cell, Animal Cell.
Functions of the eukaryotic cell
Eukaryotic cells demonstrate two elementary functions:
This means that their behaviors are governed by the most basic principles of life : `` get '' (or manufacture) `` food to '' obtain energy and, eventually, allow the perpetuation of the species through the creation of new individuals.
The latter can occur in a sexual way (usually when there is greater environmental pressure that requires greater genetic variability to find solutions) or asexual (to preserve the intact genetic code).
Parts of a eukaryotic cell
The eukaryotic cell is made up of:
- Cellular or plasma membrane . A double lipid barrier that surrounds and delimits the cell, selectively permeable: allows access to the desired substances. to the cytoplasm and also the expulsion of metabolic wastes.
- Cellular wall. Present only in plant and fungal cells, it is a rigid wall of cellulose (vegetable) or chitin (fungi). It protects the cell although it prevents its growth, constricting it to fixed structures.
- Nucleus . A central orifice where chromosomes, carriers of genetic material (DNA and RNA) are contained.
- Cytoplasm . Compound m n that nothing of water and compartments separated by internal membranes, in which they are n n nnínnnnnnnnnnnnGe nulls of the cell. These last ones can be:
- Lysosomes Con material digestive indispensable to assimilate the substances entering the cell.
- Mitochondria. The engines of the metabolic process, that is, the centers of energy through breathing or photosynthesis.
- Chloroplasts. As they contain chlorophyll, they exist only in plant cells, thanks to the pigment that contain plants have their own. Green color. Characteristic.
Difference between eukaryotic cell and prokaryotic cell
We can summarize the main differences between these two types of cells in the following points:
- Presence of the nucleus . The most important difference: in prokaryotes the genetic material is dispersed in the cytoplasm, rather than in a nucleus.
- DNA type The DNA of prokaryotes has a circular shape, and is usually simpler, while that of eukaryotes is linear (double helix) and complex.
- Size . The eukaryotes are much larger (10-100 µm) than the common prokaryotes (0.2-2.0 µm).
- Reproduction Prokaryotes reproduce asexually (mitosis or budding), while eukaryotes have both sexual (by gamete) and asexual (mitosis or other processes) reproduction.
- Or cell granules . Eukaryotes have exclusive organelles, such as mitochondria, lysosomes or chloroplasts.
More in: Prokaryotic Cell.