procariontes

Procariontes are simple, usually unicellular organisms that lack a nucleus and other membrane-bound organelles. They encompass two primary groups: Bacteria and Archaea. In contrast to eukaryotes, their genetic material is typically a single circular chromosome located in a nucleoid region, and many species carry small DNA molecules called plasmids. Most procariontes have a cytoplasmic membrane and a cell wall; in bacteria the wall often contains peptidoglycan, while in archaea it may be built from pseudopeptidoglycan, proteins, or other polymers. Some organisms lack a cell wall or possess an S-layer.

They reproduce asexually by binary fission, though genetic exchange can occur through transformation, transduction, and conjugation, enabling horizontal gene transfer and genetic diversification. Procariontes exhibit wide metabolic diversity, including phototrophy, chemotrophy, autotrophy, and heterotrophy. They inhabit virtually every environment on Earth, from oceans and soil to hot springs, acidic waters, and the human microbiome. Ecologically, they drive nutrient cycles, decompose organic matter, fix atmospheric nitrogen, and form symbiotic relationships. Some species are pathogens, while many are beneficial in food production, medicine, and biotechnology.

Cell size is typically small, and ribosomes are 70S. Evolutionarily, procariontes are classified into two domains, Bacteria and Archaea, which diverged early and show deep biochemical differences from eukaryotes. The study of procariontes spans microbiology, ecology, evolution, and applied sciences such as fermentation, antibiotics, and genetic engineering. The term procarionte is used in some languages as a counterpart to prokaryote or procaryote.