Editing Ribosome (section)

=== Plastoribosomes and mitoribosomes ===
{{main|Mitochondrial ribosome|Chloroplast#Chloroplast ribosomes}}
In eukaryotes, ribosomes are present in [[mitochondria]] (sometimes called [[mitochondrial ribosome|mitoribosomes]]) and in [[plastid]]s such as [[chloroplast]]s (also called plastoribosomes). They also consist of large and small subunits bound together with [[protein]]s into one 70S particle.<ref name="Alberts-2002" /> These ribosomes are similar to those of bacteria and these organelles are thought to have originated as [[symbiotic bacteria]].<ref name="Alberts-2002" /> Of the two, chloroplastic ribosomes are closer to bacterial ones than mitochondrial ones are. Many pieces of ribosomal RNA in the mitochondria are shortened, and in the case of [[5S ribosomal RNA#Presence in organelle ribosomes|5S rRNA]], replaced by other structures in animals and fungi.<ref>{{cite journal | vauthors = Agrawal RK, Sharma MR | title = Structural aspects of mitochondrial translational apparatus | journal = Current Opinion in Structural Biology | volume = 22 | issue = 6 | pages = 797–803 | date = December 2012 | pmid = 22959417 | pmc = 3513651 | doi = 10.1016/j.sbi.2012.08.003 }}</ref> In particular, ''[[Leishmania]] tarentolae'' has a minimalized set of mitochondrial rRNA.<ref>{{cite journal | vauthors = Sharma MR, Booth TM, Simpson L, Maslov DA, Agrawal RK | title = Structure of a mitochondrial ribosome with minimal RNA | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 106 | issue = 24 | pages = 9637–42 | date = June 2009 | pmid = 19497863 | pmc = 2700991 | doi = 10.1073/pnas.0901631106 | bibcode = 2009PNAS..106.9637S | doi-access = free }}</ref> In contrast, plant mitoribosomes have both extended rRNA and additional proteins as compared to bacteria, in particular, many pentatricopetide repeat proteins.<ref>{{cite journal | vauthors = Waltz F, Nguyen TT, Arrivé M, Bochler A, Chicher J, Hammann P, Kuhn L, Quadrado M, Mireau H, Hashem Y, Giegé P | title = Small is big in Arabidopsis mitochondrial ribosome | journal = Nature Plants | volume = 5 | pages = 106–117 | date = January 2019 | issue = 1 | doi = 10.1038/s41477-018-0339-y | pmid = 30626926 | s2cid = 58004990 }}</ref>

The [[cryptomonad]] and [[chlorarachniophyte]] algae may contain a [[nucleomorph]] that resembles a vestigial eukaryotic nucleus.<ref name="Archibald-2009">{{cite journal | vauthors = Archibald JM, Lane CE | title = Going, going, not quite gone: nucleomorphs as a case study in nuclear genome reduction | journal = The Journal of Heredity | volume = 100 | issue = 5 | pages = 582–90 | year = 2009 | pmid = 19617523 | doi = 10.1093/jhered/esp055 | doi-access = free }}</ref> Eukaryotic 80S ribosomes may be present in the compartment containing the nucleomorph.<ref>{{Cite web|title=Specialized Internal Structures of Prokaryotes {{!}} Boundless Microbiology|url=https://courses.lumenlearning.com/boundless-microbiology/chapter/specialized-internal-structures-of-prokaryotes/|access-date=2021-09-24|website=courses.lumenlearning.com}}</ref>