The eukaryotic cell has a membrane that encloses the nucleus separating it from the cytoplasm. The prokaryotic cell does not have structures with membranes inside, that is, its intracellular content is scattered in the cytoplasm.
All living things are composed of cells that, depending on their structure, can be eukaryotes or prokaryotes. The French naturalist, zoologist and biologist Édouard Pierre Léon Chatton (1883-1947) were the first to distinguish between eukaryotic organisms, those with nucleus cells, and prokaryotes, which are anucleated.
|Prokaryotic cell||Eukaryotic cell|
|Definition||A cell without a defined nucleus, its genetic material is dispersed in the cytoplasm.||Cell with a nucleus defined by a membrane that contains the genetic material.|
|Size||Between 1 and 10 microns.||Between 10 and 100 microns.|
|Shape||It can be spherical, cane, spelling, or spiral. Although they are unicellular, they can form colonies.||Very varied, they can constitute unicellular or multicellular organisms.|
|Genetic information||Located in a nucleoid, without being surrounded by a membrane.||DNA and proteins from the chromatin that is concentrated in the nucleus|
|Cellular division||Direct, mainly by binary fission. There is no mitotic spindle or microtubules.||For mitosis and meiosis. It has a mitotic spindle or some form of microtubule management.|
|Genes||Expressed in groups called operons.||Expressed individually; They have introns and exons.|
|Ribosomes||Present but small (70S)||Present and large (80S)|
|Flagellum||Simple, formed by the flagellin protein.||Composed, formed by tubulin and other proteins.|
|Chromosomes||Single circular chromosome.||Multiple. Each with two chromatids, centromere, and telomeres.|
|Cellular wall||Present||Only present in plants and fungi.|
|Domains||Bacteria and Archaea||The Eukarya domain that groups plants, animals and fungi.|
|Examples||The bacterium Staphylococcus aureus, archaeus Halobacterium salinarum.||The yeast of the Saccharomyces cerevisiae bread, the fruit fly Drosophila melanogaster, the banana or banana Musa sp.|
What is a eukaryotic cell?
The eukaryotic cell is the building block of the life of protozoa, fungi, plants, and animals. It is characterized by keeping its genetic material packaged within a membrane, forming the nucleus. It also has other intracellular structures surrounded by membranes, known as organelles: mitochondria, vesicles, chloroplasts, among others.
The word “eukaryote” comes from the Greek EU, which means “true” and karyon, which means “nut or kernel.” The eukaryotic cell is the basis for the classification of organisms within the Eukarya domain.
Characteristics of eukaryotic cells
- Varied forms: depending on the environment where the cell is located, it can be spherical, cubic, pyramidal, flat or starry.
- Varied sizes: eukaryotic cells can measure from 10 µm (like lymphocytes), up to 100 µm (like adipocytes or fat cells).
- Varied functions: Although eukaryotic unicellular beings, such as parasites, must perform all the functions necessary for their survival, in multicellular beings there are cells with different functions. For example, intestine cells are designed to absorb nutrients and send them to the blood, from where they are distributed. Plant root cells absorb nutrients and water from the soil.
- Presence of organelles: within the eukaryotic cell there are structures specialized in specific functions, including chloroplasts, the Golgi apparatus, mitochondria, vesicles and lysosomes.
Classification of eukaryotic cells
There are two large groups of eukaryotic cells: the animal cell and the plant cell. A special case is found in fungal cells, which share characteristics of both animal and plant cells.
The animal cell has a plasma membrane, nucleus and cytoplasm. The genetic material is stored inside the nucleus and is composed of the nucleoplasm and the nuclear envelope. In the cytoplasm most of the chemical reactions necessary for the proper functioning of the cell occur.
Animal cells have a plasma membrane composed of lipids and proteins, which is the barrier that prevents or allows the entry and exit of compounds into the cell. Since the animal cell does not perform photosynthesis, it does not have chloroplasts. Nor does it have a cell wall, like the plant cell.
Characteristic examples of animal cells are neurons in the nervous system, leukocytes of the immune system, ovules and sperm of the reproductive system.
Like the animal cell, it has a differentiated nucleus, membrane, and cytoplasm. However, the plant cell contains chloroplasts, structures that are responsible for the process of photosynthesis.
Thanks to photosynthesis, plants absorb energy from the sun and capture carbon dioxide to synthesize organic compounds and release oxygen into the atmosphere.
In addition, plant cells have a cell wall, an external structure that covers the plasma membrane. The cell wall gives support and protection to the cell while allowing intercellular communication.
Fungal cells are eukaryotes and share common characteristics with animal and plant cells:
- They have a cell wall like plant cells, whose chemical composition (chitin) varies depending on the species.
- They do not perform photosynthesis, so their cells do not have chloroplasts, like the animal cell.
Related Articles: Difference Between Animal and Plant Cell
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