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Eukesh (खँल्हाबल्हा | योगदान) |
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क्लोरोप्लास्ट धाःगु खंग्वः युनानी खँग्वः ''क्लोरोस'' अर्थात वांगु व ''प्लास्ट'' अर्थात एन्टिटि स्वाना वःगु खंग्वः ख। क्लोरोप्लास्ट [[प्लास्टिड]] नां दूगु अर्ग्यानेल क्लासया छगू सदस्य ख।
==वैकाशिक उत्त्पत्ति==
[[Image:Chloroplasten.jpg|thumb|right|250px|वनस्पति सेलय् खने दूगु क्लोरोप्लास्ट।]]
▲Chloroplasts are one of the many different types of organelles in the cell. They are generally considered to have originated as [[endosymbiotic theory|endosymbiotic]] [[cyanobacteria]] (i.e. blue-green algae). This was first suggested by [[Konstantin Mereschkowski|Mereschkowsky]] in 1905 <ref>{{cite journal | author= Mereschkowsky C | title= Über Natur und Ursprung der Chromatophoren im Pflanzenreiche | journal= Biol Centralbl | year=1905 | volume=25 | pages=593–604}} </ref> after an observation by Schimper in 1883 that chloroplasts closely resemble cyanobacteria. <ref>{{cite journal | author= Schimper AFW | title= Über die Entwicklung der Chlorophyllkörner und Farbkörper | journal= Bot. Zeitung | year=1883 | volume=41 | pages=105–14, 121–31, 137–46, 153–62}} </ref> All chloroplasts are thought to derive directly or indirectly from a single endosymbiotic event (in the [[Archaeplastida]]), except for ''[[Paulinella]] chromatophora'', which has recently acquired a photosynthetic cyanobacterial endosymbiont which is not closely related to chloroplasts of other eukaryotes.<ref>{{cite journal | title = Diversity and evolutionary history of plastids and their hosts | author = Patrick J. Keeling | url = http://www.amjbot.org/cgi/content/full/91/10/1481 | journal = American Journal of Botany | year = 2004 | volume = 91 | pages = 1481–1493 | doi = 10.3732/ajb.91.10.1481}}</ref> In that they derive from an endosymbiotic event, chloroplasts are similar to [[mitochondrion|mitochondria]] but chloroplasts are found only in [[plant]]s and [[protist]]a. The chloroplast is surrounded by a double-layered composite membrane with an intermembrane space; further, it has reticulations, or many infoldings, filling the inner spaces. The chloroplast has its own [[DNA]] which codes for redox proteins involved in electron transport in photosynthesis.
In green plants, chloroplasts are surrounded by two [[cell membrane|lipid-bilayer membrane]]s. The inner membrane is now believed to correspond to the outer membrane of the ancestral cyanobacterium. Chloroplasts have their own genome, which is considerably [[genome reduction|reduced]] compared to that of free-living cyanobacteria, but the parts that are still present show clear similarities with the cyanobacterial genome. Plastids may contain 60-100 genes whereas cyanobacteria often contain more than 1500 genes.<ref>{{ cite journal | author= Martin W, Rujan T, Richly E, Hansen A, Cornelson S, Lins T, Leister D, Stoebe B, Hasegawa M, Penny D | title= Evolutionary analysis of Arabidopsis, cyanobacterial, and chloroplast genomes reveals plastid phylogeny and thousands of cyanobacterial genes in the nucleus | journal = Proc Natl Acad Sci | year = 2002 | volume=99 | pages=12246–12251 | doi= 10.1073/pnas.182432999 | pmid= 12218172}}</ref> Many of the missing genes are encoded in the nuclear genome of the host. The transfer of nuclear information has been estimated in [[tobacco]] plants at one [[gene]] for every 16000 pollen grains.<ref>{{cite journal | author=Huang CY, Ayliffe MA, Timmis JN | title=Direct measurement of the transfer rate of chloroplast DNA into the nucleus | journal=Nature | date =2003-03-06 | volume=422 | issue=6927 | pages=72–6 | doi=10.1038/nature01435}}</ref>
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