What organisms are prokaryotes? Prokaryotes are amazing and diverse creatures. They can live in almost any environment, create and receive vital energy in various ways, and some of them are even predators.
Prokaryotes: general information
What organisms are prokaryotes? These are the most numerous organisms that inhabit planet Earth. The current classification of prokaryotic species is based on a combination of genomic and phenotypic properties. The number of known species of prokaryotes currently exceeds 6,200. These organisms appeared on Earth earlier than anyone and continue to exist safely today.
Interesting facts and a brief description of prokaryotes
1) Prokaryotes live wherever there is life, and it would seem that there can be no life, since these organisms can survive in a cold, hot, acidic and alkaline environment.
2) Prokaryotes were even discovered at a depth of about 3 km below the surface of the Earth.
3) Most prokaryotes are a variety of unicellular organisms with excellent adaptive ability.
4) Many individuals are motile, approximately half of all prokaryotes are capable of directional movement.
5) Prokaryotic cells are simpler than eukaryotes, both in internal structure and in genomic organization.
6) Prokaryotic populations grow and adapt quickly.
7) Under favorable conditions, a single cell is able to produce a huge colony of offspring in a fairly short time.
8) Researchers regularly freeze colony samples so that, after thawing, they conduct additional experiments and continue to study the characteristics of these tenacious creatures.
Food adaptation
In a detailed examination of the question of which organisms belong to prokaryotes, the method of obtaining food occupies an important place. So, organisms that receive energy from light are phototrophs, and chemotrophs as a result of chemical reactions. Organisms that need only carbon dioxide (CO 2 ) as a carbon source are autotrophs. Living organisms that require at least one source of organic nutrient (glucose) are heterotrophs.
Photoautotrophs are photosynthetic organisms that use the energy of light to stimulate the synthesis of organic compounds from carbon dioxide (plants and algae). Chemotrophs only need carbon dioxide as a carbon source, but they can also get energy by oxidizing inorganic substances (hydrogen sulfide (H 2 S), ammonia (NH 3 ) and iron ions (Fe 2+ )). This food method is unique to prokaryotes.
Habitat
As for the habitat of prokaryotes, it can be the most diverse. Many features of prokaryotes are associated with the fact that these microorganisms are able to survive in the most extreme conditions: increased salinity, extremely high temperatures, places devoid of oxygen. Prokaryotes can live in the body of animals and people, helping the host through symbiosis perform the functions of his body (digestion).
Prokaryotes are obtained from a wide variety of sources. This may be a search for dead cells or hunting for living (extremely rare). The most common method of obtaining the necessary nutrients is to create energy through photosynthesis or the use of other minerals such as sulfur.
Types and structure of prokaryotes
What organisms are prokaryotes? There are two main types: bacteria and unicellular organisms. Prokaryotic cells include a plasma membrane, cytoplasm, ribosomes, and genetic material (DNA and RNA). Some species also have additional structures - the cell wall, flagella and others. The structure of prokaryotic cells, each of the structures and cellular components play a crucial role in growth, survival and reproduction.
Plasma membrane
Prokaryotic cells may have multilayer plasma membranes. Prokaryotes, known as gram-negative bacteria, for example, often have two plasma membranes between which there is the so-called periplasm. As in all cells, the plasma membrane in prokaryotic cells is responsible for the management and control of everything that is part of the cell.
Through the membrane, communication occurs, including sending and receiving chemical signals from other bacteria and interaction with the cells of eukaryotic organisms during infectious processes. It should be borne in mind that the plasma membrane is universal for both prokaryotic and eukaryotic cells.
Cytoplasm
The cytoplasm in prokaryotic cells, resembling a gel or jelly, is a liquid substance in which all other cellular components are located. Recently, biologists have discovered that prokaryotic cells have a complex and functional cytoskeleton similar to what eukaryotic cells have. Thus, the cell can maintain its shape.
Ribosomes
Prokaryotic ribosomes are smaller and have a slightly different shape and composition than those found in eukaryotic cells. The functions of this cellular component are also identical - the construction of proteins and the transmission of signals that DNA sends.
Genetic material
All prokaryotic cells contain a large amount of genetic material in the form of DNA and RNA. Prokaryotes include organisms whose cells do not have a nucleus, the only large round section of DNA that contains most of the genes necessary for the growth, survival and reproduction of cells. DNA in such cells is presented in random order.
As a rule, DNA extends throughout the cell in order to be decrypted into RNA and transformed. In a microscope, you can see the densification in a certain part of the cell, this is the genetic material (DNA). In addition to a single large portion of chromosomal DNA, many prokaryotic cells also contain small pieces of DNA called plasmids. These round DNA rings are copied independently of the chromosome and can be transferred from one prokaryotic cell to another.
Thanks to its features, prokaryotes can safely survive in any conditions, they are everywhere - both in the usual environment, and in salt lakes, hot springs, in the craters of volcanoes and deep in the bowels of the Earth. Thus, the most resistant and viable organisms on the planet belong to prokaryotes.