Prokaryotic cell - the cell of the pre-nuclear organism

A prokaryotic cell is, in fact, justan organized organism that preserves the traits of distant ancestors. They are systematically separated into a separate kingdom of the seed, which includes bacteria and cyanobacteria (blue-green algae).

What is so “simple” in the structure of pre-nuclearorganisms? A prokaryotic cell does not have a nucleus surrounded by its own membrane, mitochondria and plastids. In the center of the cytoplasm is a nucleoid (nucleotide), which consists of a single nucleprotein structure containing a circular DNA molecule. This complex is called the bacterial chromosome. The cell itself of bacteria and blue-green algae from the external environment is separated by a dense cell wall or mucous capsule and membrane. The wall of an elementary structural unit mainly consists of the substance of murein (formed by proteins and carbohydrates), which performs the function of the external skeleton, giving the shape of a cell and protecting it from external stimuli. The inner membrane performs the following functions: protective, transport, perception of irritation and demarcation.

Внутреннее строение прокариотической клетки suggests that the cytoplasm and its composition is much poorer than that of the nuclear (eukaryotic). It contains ribosomes, which are necessary for protein synthesis. There are also membrane structures that perform the functions of missing organelles - mitochondria, the endoplasmic reticulum, the Golgi apparatus and the plastids. For example, a prokaryotic cell has a membrane protrusion called the mesosome. This is where the process of respiration and the release of energy in bacteria.

Also pre-nuclear organisms are capable ofsporulation, but they do not reproduce with their help. Spores or cysts are dense membranes that help bacteria survive adverse conditions. To maintain life in unusual conditions, they are able to accumulate nutrients - fats, complex carbohydrates.

Prokaryotic cell can multiplydivision, budding and conjugation. The breeding method depends on the type of bacteria or cyanobacteria. Division and budding are ways that allow you to quickly increase the population size. Conjugation, which occurs in Escherichia coli, is a sexual process that contributes to hereditary variability in microorganisms.

Thus, prokaryotes are pre-nuclear cells,which do not have a formed cell nucleus and are devoid of many membrane organelles, but capable of changing. They were the ones who were able to adapt to life in conditions in which no one else survives - the atomic reactor, oil wells. A huge number of representatives of the kingdom of the seed are pathogenic and can cause various diseases in people, animals and plants (dysentery, angina, tuberculosis). Also, some microorganisms live in symbiosis with eukaryotes (symbiogenesis), for example, nitrogen-fixing nodule bacteria that live on the roots of legumes.