A prokaryotic cell is, in fact, just an organized organism that retains the features of distant ancestors. They have been systematically separated into a separate kingdom of blaster, which includes bacteria and cyanobacteria (blue-green algae).
What is so "simple" in the structure of pre-nuclear organisms? A prokaryotic cell does not have a nucleus surrounded by its own membrane, mitochondria and plastids. In the center of the cytoplasm is the nucleoid (nucleotide), which consists of a single nucleoprotein structure containing a circular DNA molecule. This complex is called the bacterial chromosome. The cell itself of bacteria and blue-green algae is separated from the external environment by a dense cell wall or mucous capsule and membrane. The wall of the elementary structural unit mainly consists of the murein substance (formed by proteins and carbohydrates), which performs the function of the external skeleton, shaping the cell and protecting it from external stimuli. The inner membrane performs the following functions: protective, transport, perception of irritations and delimitation.
The internal structure of a prokaryotic cell suggests that the cytoplasm and its composition is much poorer than that of a nuclear (eukaryotic) cell. It contains ribosomes, which are necessary for protein synthesis. There are also membrane structures that perform the functions of missing organelles - mitochondria, endoplasmic reticulum, Golgi apparatus and plastids. So, for example, a prokaryotic cell has a protrusion of the membrane, which is called the mesosome. It is here that the process of respiration and energy release occurs in bacteria.
Also, pre-nuclear organisms are capable of sporulation, but they do not reproduce with their help. Spores or cysts are tough shells that help bacteria survive unfavorable conditions. To maintain life in conditions unusual for them, they are able to accumulate nutrients - fats, complex carbohydrates.
Prokaryotic cell can reproduce by division, budding and conjugation. The method of reproduction depends on the type of bacterium or cyanobacteria. Division and budding are methods that allow you to quickly increase the population size. Conjugation, which occurs in E. coli, is a sexual process that contributes to increased hereditary variability in microorganisms.
Thus, prokaryotes are pre-nuclear cells that do not have a well-formed cell nucleus and lack many membrane organelles, but are capable of changing. It was they who were able to adapt to life in conditions in which no one else survives -nuclear reactor, oil wells. A huge number of representatives of the kingdom of shotguns are pathogenic and can cause various diseases in humans, animals and plants (dysentery, tonsillitis, tuberculosis). Also, some microorganisms live in symbiosis with eukaryotes (symbiogenesis), for example, nitrogen-fixing nodule bacteria that settle on the roots of legumes.
