پروڪئريوٽ

پروڪئريوٽ (prokaryote) هڪ-گھرڙي وارا جاندار آهن، جنهن جي جيو گھرڙي ۾ نه اي نيوڪليس هجي ۽ نه اي ٻيا جھلي سان جڙيل عضوا هجن. لفظ پروڪئريوٽ قديم يوناني لفظ "πρό" (پرو، معنيٰ اڳي) ۽ "κάρυον" (ڪارون، معني، مغز يا گٺلي) مان ورتل آهي. ائڊورڊ چٽن جي ڪم مان پيدا ٿيندڙ ٻن-ڪنگڊم واري نظام ۾، پروڪئريوٽ کي ڪنگڊم پروڪئريوٽا (Prokaryota) ۾ ورهايو ويو. تنهن هوندي به ٽن ڊومين جي نظام ۾، ماليڪيولر تجزيي جي بنياد تي، پروڪئريوٽ ٻن ڊومين ۾ ورهايل آهن؛ بيڪٽيريا (اڳوڻو يوبئڪٽيريا) ۽ آرڪيا (اڳوڻو آرڪي بئڪٽيريا). نيوڪليس سان گڏ جيو گھرڙن وارا جاندار، يوڪيريئوٽ ٽين ڊومين ۾ شامل آهن.

Diagram of a typical prokaryotic cell

A prokaryote (/proʊˈkærioʊt[unsupported input]-ət/; less commonly spelled procaryote) is a single-cell organism whose cell lacks a nucleus and other membrane-bound organelles. The word prokaryote comes from the Ancient Greek (سانچو:Grc-transl), meaning 'before', and (سانچو:Grc-transl), meaning 'nut' or 'kernel'. In the two-empire system arising from the work of Édouard Chatton, prokaryotes were classified within the empire Prokaryota. However in the three-domain system, based upon molecular analysis, prokaryotes are divided into two domains: Bacteria (formerly Eubacteria) and Archaea (formerly Archaebacteria). Organisms with nuclei are placed in a third domain: Eukaryota.

Prokaryotes evolved before eukaryotes, and lack nuclei, mitochondria, and most of the other distinct organelles that characterize the eukaryotic cell. It was once thought that prokaryotic cellular components were unenclosed within the cytoplasm except for an outer cell membrane, but bacterial microcompartments, which are thought to be quasi-organelles enclosed in protein shells (such as the encapsulin protein cages), have been discovered, along with other prokaryotic organelles. While being unicellular, some prokaryotes, such as cyanobacteria, may form colonies held together by biofilms, and large colonies can create multilayered microbial mats. Others, such as myxobacteria, have multicellular stages in their life cycles. Prokaryotes are asexual, reproducing via binary fission without any fusion of gametes, although horizontal gene transfer may take place.

Molecular studies have provided insight into the evolution and interrelationships of the three domains of life. The division between prokaryotes and eukaryotes reflects the existence of two very different levels of cellular organization; only eukaryotic cells have an enveloped nucleus that contains its chromosomal DNA, and other characteristic membrane-bound organelles including mitochondria. Distinctive types of prokaryotes include extremophiles and methanogens; these are common in some extreme environments.