In addition to organelles or organelles, eukaryotic cells have specialized subcellular structures that are delimited by membranes, examples of which are mitochondria and chloroplasts.
The origin of eukaryotes is not very clear, but scientists suggest that their formation may be related to the symbiosis between a bacterium and an archaea, which over the years became one, that is, a single organism.
Thanks to these cells, the planet contains a great diversity of organisms of different species classified into four kingdoms: animalia , plantae, fungi and protista. Although it is true that the other type of cells, prokaryotes , are also involved in the evolution of biodiversity.
These cells carry out three important functions for their survival and for the organism that they compose:
- Nutrition: cells can be autotrophic or heterotrophic. The former make their own food and the latter take it from organic matter. Nutrients are transformed into other usable substances in the restructuring of the cell or to obtain energy.
- Relationship with the environment: eukaryotes are capable of reacting according to the stimulus they receive from the environment that surrounds them. They can be factors such as temperature, acidity or humidity, thanks to that they can be transferred, for example.
- Reproduction: through its reproduction process, new cells are formed, only from a stem cell. This process can be mitosis (it generates two daughter cells with the same genetic load ) or meiosis (it produces four daughter cells with different genetics).
Eukaryotic cell types
Animal cell: they are present in animal tissues. Unlike vegetables, these have smaller and larger centrioles and vacuoles. On the other hand, they also differ from plants in that they do not have rigid cell walls, but rather a lipid bilayer, nor chloroplasts, which is where photosynthesis takes place.
Plant cell: they are contained in plants. The cell wall is made up of cellulose and proteins. This wall covers the plasma membrane giving it toughness that helps protect them. The chlorophyll necessary for photosynthesis is found in these cells.
Fungal cells: they have a lot of similarity to animal cells, only that they have a cell wall made up of chitin and are less well defined. In addition, the pores in this wall allow the passage of organelles between cells.
Cell or plasma membrane. It is a layer composed of lipids and proteins that covers and defines the cell. This membrane can allow only necessary substances to enter the cytoplasm, and it also allows the expulsion of metabolic wastes.
Cellular wall. It is a rigid structure that is located outside the plasma membrane and that shapes the cell in addition to providing protection.
Cell nucleus. It is a central organelle that houses the DNA and that allows the flow of material between the cytoplasm and its interior. In this structure, specifically within the nucleolus, ribosomes are formed.
Ribosomes. They are structures made up of RNA and proteins. Protein synthesis takes place in them. Some ribosomes are freely within the cytoplasm and others are completely attached to the rough endoplasmic reticulum.
Cytoplasm . It is made of aqueous material in which the different organelles of the cell are found. The cytoplasm is made up of the cytosol and the cytoskeleton, which shapes the cell.
Lysosomes . They are kind of vesicles full of digestive enzymes , which are only found in animal cells. This is where cellular digestion takes place, using the enzymes found inside.
Mitochondria . They are organelles that allow the cellular respiration process. They have a double membrane that allows to obtain the energy that the cell needs to fulfill its functions.
Chloroplasts . They are the most complex organelles present in plant cells, where photosynthesis takes place. The most important component of these organelles is chlorophyll.
Large vacuole. It is a type of gallbladder that stores water, mineral salts, and other substances. It is large in size and is only found in plant cells, although animal cells have a smaller version and in less quantity.
Centrioles . They are tubular in shape and found only in animal cells. It is a fundamental structure in the separation of chromosomes in the process of cell division.
Endoplasmic reticulum. It is a whole system of membranes that goes from the cell nucleus and that extends throughout the cell. It participates directly in the synthesis of substances destined mainly for the exterior of the cell.
Golgi apparatus. It is a structure that constitutes a set of flat discs and sacks called cisterns. Its function is to modify and package proteins and other biomolecules for their secretion or transportation.
Examples of eukaryotes
- Protista plasmodium
- Red blood cell