Talk:Organelle

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[edit] Old comments

Which organelles are not bounded by membranes.

None? --G3pro 12:38, 28 Oct 2004 (UTC)
If you call the cytoskeletton an organelle, it is not membrane-bound. Neither Ribosomes are bound by membranes nor is the centrioles. --Eribro 17:35, 5 June 2006 (UTC)

I created a disambiguation for vesicle and have been going back and changing the links in all the biology articles to link to vesicle (biology). If you would modify (or enable me to modify) the link in this article to vesicle to point instead to vesicle (biology), I would appreciate it. Jared81 -- (I moved this comment from elsewhere to the correct place for him, since this page is protected. Lachatdelarue (talk) 22:15, 4 Jun 2005 (UTC))

Done. Since the page is protected due to vandalism rather than an edit war, it's fine for admins to make minor fixes. -- Hadal 04:48, 5 Jun 2005 (UTC)

The Organelle template has been updated to reflect the movement of the Vesicle article to Vesicle (biology). Pages that use this template have had their links updated fine. however, the "what links here" page for Vesicle still lists all the pages that use the organelle template as linking to vesicle. Editing the entry, making no changes and saving it, is all you have to do to update the list of "what links here" for the vesicle article. So if you would, please edit this page and immediately save it and mark it as a minor edit. Thanks. Jared81 08:17, Jun 5, 2005 (UTC)

Hi guys. This page didn't help me understand what 'organelles' are. Can someone add a clear, defining intro sentence? Much appreciated. martin

"An organelle is is to the cell what an organ is to the body (hence the name ORGANelle)." I Hope it made things clearer. --Eribro 17:21, 5 June 2006 (UTC)

[edit] Vesicle/Vacuole

I thought only plant cells had vakoules, the picture shows one and it's supposed to be a picture of an animal cell. Does animal cells have vakuoles? --Eribro 17:33, 5 June 2006 (UTC)

Animal cells do not have vacuoles, the vacuolar equivalent are the lysosomes. See this chapter of the textbook "Molecular Biology of the Cell" (also cited as a reference for the article).--Biologos 13:22, 15 March 2007 (UTC)

A vacuole is the equivelent of an air bubble. Plant cells usually have 1 or 2 large ones, but animal cells can have several but they are much smaller. Bartimaeus 13:10, 12 October 2006 (UTC)

[edit] Ribosomes are organelles?

This definition of Organelle is strongly misleading or the list of organelles is incomplete. I understand the reasoning behind the idea of including also some non membrane-enclosed organelles such as centrioles. But to entitle ribosomes as organelles reaches out to far. First of all, their number (100000 to 10000000 per cell) is a major difference. Secondly, what about proteasomes? Degradosomes? Chaperones? Members of each family are comparable in size and importance, yet they are not considered as organelles.

Defining 'organelle' seems surprisingly difficult - literature is not united on that. But to include protein complexes, just because they are large and have a certain function, doesn't make the definition of 'organelle' useful at all. --141.61.1.25 14:02, 4 January 2007 (UTC)Stefan

I Agree Ribosomes are not organelles. Organelles must be membrane bounded. While some people stretch the definition to include the cytoskeleton, even this isn't appropriate. I am a professor at a medical school, and find that this entry is misleading students... Sludtke42 20:51, 8 May 2007 (UTC)


[edit] First usage of "Organelle"?

In the German Wikipedia we are currently struggling with the correct definition of Organelle. It was sort of comforting that you have the same problem here... I came to the conclusion that different Authors use different definitions, sometimes limited to membrane bound organelles and sometimes including structures like centrioles. I feel that in this situation it would be helpful to know (and then to include in the article) who introduced the term and how it was then defined. Does anybody have an idea? If so, please let me know. The oldest usage I found (through Google Scholar) was 1919, [here] but it appears that it was already accepted nomenclature by then. If anyone could help, that would be great. --Dietzel65 14:56, 20 October 2007 (UTC)

The origin is probably lost in the mists of time. Google Books is a good resource for this sort of thing. I found a 1907 usage from Transactions of the Pathological Society of London:
From the base of the rostrum there can be seen a slender, somewhat sinuous line or tube running through the middle of the anterior portion of the body to a point about halfway between the anterior extremity and the nucleus. It appears to be a permanent and definite organelle.
The earliest I came up with was from 1903, in German, at [1].
I have a 1970 textbook (Novikoff & Holtzman, Cells and Organelles) that discusses the definition problem:
But must a structure be membrane-bounded to qualify as an organelle? As techniques improve, less and less of the cell appears unstructured, but only some of the organization involves membranes. Nucleoli, chromosomes, ribosomes, centrioles, and microtubules all are distinctively structured and have specialized roles in the cell, but no membrane surrounds them. The non-membrane—bounded organelles grade down in size and complexity to protein filaments composed of a few hundred molecules. At the lower end of the size spectrum, the distinctions between organelle and macromolecule become difficult to define and perhaps meaningless. Should a multienzyme complex, in which a few or a few dozen enzymatically active protein molecules are complexed as a functional unit, be called an organelle or a molecular aggregate? Are nucleoli to be considered organelles despite their being contained in other organelles (nuclei)? The decision appears to be a matter of arbitrary definition.
It seems that a widely-accepted definition is unlikely to be found. It really has a long history as a vague term, centering on an idea something like "a sub-cellular identifiable component". It has a vagueness similar to that of the word organ, from which it was derived (Is the skin an organ? etc etc). -R. S. Shaw 20:49, 20 October 2007 (UTC)
Maybe it's not so lost. Consulting the Oxford English Dictionary for organelle, it leads to the earlier organella, which has this interesting 1889 quote from Amer. Naturalist 23 183 (note): "It may possibly be of advantage to use the word organula here instead of organ, following a suggestion by Möbius. Functionally differentiated multicellular aggregates in multicellular forms or metazoa are in this sense organs, while for functionally differentiated portions of unicellular organisms or for such differentiated portions of the unicellular germ-elements of metazoa the diminutive{em}organula{em}is appropriate."
The OED's etymology for organella gives this:
after German Organulum (K. Möbius 1884, in Biol. Centralbl. 4 392; O. Bütschli H. G. Bronn's Klassen u. Ordnungen des Thier-Reichs (1888) I. III. 1412) < classical Latin organum ORGAN n.1 + -ulum -ULE suffix.
This suggests the original use was for "functionally differentiated portions of unicellular organisms", a broad definition. -R. S. Shaw 18:23, 22 October 2007 (UTC)


Wow, great answer! Thanks for the tip with Google books. I keep getting funny results though, where the publication date obviously does not fit the content of the snippets (around 1900 with heat shock protein details and the like) Anyway, I found this one [2] which claims to be from 1877, that would predate Möbius if true. I just ran another search with Organulum OR Organula OR Organella and found this [3] from 1844 but I am afraid I don't read latin. I have the impression though that this is not about biology. This [4] French snippet seems to confirm the Möbius origin though. Very confusing, I'll try to find out more some other day, night is calling around here. --Dietzel65 21:11, 22 October 2007 (UTC)

Yeah, you need to be careful about the dates Google Books presents. Apparently for serials (journals, periodicals, etc) they just give the year of the first issue regardless of when the issue of the search-hit was published. -R. S. Shaw 05:17, 23 October 2007 (UTC)
Dear R. S. Shaw, would it be possible for you to check again the American Naturalist citation? I have got a copy of the article spanning page 183 in the Amer. Naturalist from 1889 (23), but this article is about Anthropology, nothing about organelles. Maybe the OED is wrong? --Dietzel65 13:49, 30 October 2007 (UTC)
Here's a copy and paste of the ref: "Amer. Naturalist 23 183 (note)" (but hand modified for bold/italic). I take this to indicate the quote is from a footnote on p. 183 of vol. 23. The (online) OED entry for the word is labeled "DRAFT ENTRY Sept. 2004" so perhaps the ref hasn't been rechecked or something; maybe the page or vol number is wrong. The year attributed to the quote is 1889. -R. S. Shaw 04:08, 31 October 2007 (UTC)
Thanks a lot. Looks like we have a wrong reference then. The copy I have says in the heading of each double-page "The American Naturalist. March, 1889. Archæology and Anthropology (or Microscopy)." The copy runs from page 178 to 190. From 178 to 188, there is an article about anthropometry, on p 188 is a note about the staining of the eggs of Petromyzon, on p189 starts "Central nervous system of Lumbricus". There is no footnote on p. 183. I can't exclude that the library made a mistake and there is another volume from 1889 (not the 23) from which I got the copy, but I don't think so. I believe the online-OED is for subscribers only. Maybe you want to inform them about their mistake and they will be so embarrassed that they try to correct it themselves :-). I'll be happy to send you the copy as file by e-mail if you want it, it is only 690 k. Thanks again for your help. --Dietzel65 08:07, 31 October 2007 (UTC)
I've sent an inquiry to OED. The volume number seems to correspond to the year (judging by Google Book images for 1882 and 1894 volumes); the volumes seem to match calendar years. -R. S. Shaw 20:25, 31 October 2007 (UTC)

Regarding the Möbius origin for the term, Google Books may not have the original article, but it does have a correction to it, which is precisely of a sentence proposing use of the term 'Organula'. It is at [5]. -R. S. Shaw 20:25, 31 October 2007 (UTC)

I've tried the link, but keep getting Google Server Errors. Maybe another day. For the time being I kept the citation from the OED in the new section (see below), hopefully to be corrected later. --Dietzel65 22:23, 31 October 2007 (UTC)
I don't know why it wasn't working for you (it works for me from a non-logged-in separate browser). An alternative is to try a search for "S 392 Z 17 v o" and click on the one hit. It says gehört zu „Organula" folgende Anmerkung: Die „Organe" der Heteroplastiden bestehen aus vereinigten Zellen. Da die Organe der Monoplastideu nur verschieden ausgebildete Teile einer Zelle sind, schlage ich vor, sie „Organula" zu nennen. K. Möbius. -R. S. Shaw 05:27, 1 November 2007 (UTC)

No more Google Server errors now but I feel I still don't see what you are seeing. I am afraid this may be a consequence of this: "For users outside the U.S., we make determinations based on appropriate local laws." (Citation from Google Books help page). I don't think German an US copyright are much different when it comes to the expiration date but maybe the Google data base doesn't know that. When I do the search you suggested, I don't get a snippet view and I don't see the sentence that you cited in the paragraph just above. Anyway, this citation is most likely the first usage of Organulum, but I cannot find the exact reference. Is that from "Biologisches Centralblatt"? If so, I would probably be able to get the original tomorrow (Monday) if I had the volume and page number.--Dietzel65 15:45, 4 November 2007 (UTC)

Google identifies the source as "biologisches centralblatt / By j. rosenthal / Published 1885 / Original from Oxford University". The masthead on page 1 gives "IV. Band.- 1. März 1884. - Nr. 1." The list of corrections the quote above is from is on page 448 (I don't know the official volume or issue number). I have emailed you an image of the page. -R. S. Shaw 23:44, 4 November 2007 (UTC)
I didn't get the e-mail (got the one with the OED link twice, though) but the citation was enough to find it in the book today. I made a copy and plan to put it online later this week, as work permits. Thanks again, for the citation as well as the OED link. --Dietzel65 22:06, 5 November 2007 (UTC)
I've put the Möbius-article online and included the URL in the reference. --Dietzel65 21:06, 6 November 2007 (UTC)

[edit] Word History and Definitions

Thanks to the help of R. S. Shaw and several others on de:Diskussion:Organell and some digging through the literature I was able to compile a short history of the term organelle and its definition over time for the German Wikipedia (see de:Organell). I think it helps a lot to cope with the question of how organelles are defined, i.e. does a structure need to have a membrane to be an organelle. My conclusion is that two different definitions are currently in use and both should be reflected in the article. Accordingly the German organelle article got a complete make over (I am not planning to do this here, though). The tables in English version helped a lot to get this done in a reasonable (well, ) amount of time.

Anyway, to get back to the point, I felt I should give back to the English speaking and international community by translating the respective chapter and here it is. A problem that arose is that the new part does not really fit into the structure of the rest of the article. Which is suffering from the definition problem anyway and thus could use a make over.... Obviously, my selection of text books cited is leaning to German ones, maybe not appropriate for the English version. Feel free to improve this or my English, it's a wiki.

In case you care, I found the following structure helpful to reorganize the German Organell article:

membrane bound organelles
semi autonomous Os
other frequent membrane bound Os.
animal cells
plant cells
specialized membrane bound Os
cell type specific Os from multicellular beings
Species specic Os from protists and mosses
eukaryotic Os w/o membrane
procaryotic Os

--Dietzel65 22:23, 31 October 2007 (UTC)

By the way, I'm coming around to the idea that "membrane bound" should be avoided, using "membrane enclosed" or "membrane bounded" instead. The problem is that bound normally means attached to, and is used this way in biology, as in the phrase "membrane bound protein". If one accepts that "organelle" may include non-membrane-enclosed things, then those things might well be attached to a membrane (and thus be membrane-bound). One could imagine a membrane-enclosed structure attached to a separate membrane (perhaps that's fantastic, but why add confusion?). And if one were to say that if it's a membrane-enclosed organelle than the word bound means enclosed by but if the context is other things like proteins, then bound means attached to, the problem is that it presumes that the reader already knows what is meant; if he does not, he is totally lost by the usage rather than being informed by it. Hence I'm thinking of changing most usages to "membrane-enclosed". -R. S. Shaw 01:02, 5 November 2007 (UTC)

[edit] Compartment and DNA containing

The first paragraph of "Examples" contains two statements I would like to discuss:

  • 'While most cell biologists consider the term organelle to be synonymous with "cell compartment" '. As a cell biologist, I would argue that this is plain wrong, meaning: whoever wants to make this statement should cite robust references that 'most' cell biologists think so. A compartment is some sort of reaction room, e.g. the inside of Mitochondria, all right. However, I found one text book definition that said the respective compartment would be the sum of all respective rooms within a cell, i.e. there may be many Mitochondria in one cell, but only one mitochondrial compartment. The cytoplasma is a compartment but not an organelle. The interchromatin compartment in the nucleus is not an organell. Flagella may be defined as organelles but I doubt they can be regarded as compartments.
  • 'other cell biologists choose to limit the term organelle to include only those which are DNA-containing'. Is there any reference for this? We had a discussion about this on de:Diskussion:Organell but nobody could come up with a citeable source. So we dropped it for the time being. If substantiable, I think it should be incorporated in the previous chapter about terminology.

--Dietzel65 16:09, 4 November 2007 (UTC)

Those sentences definitely need weakening, if not removal, in my view. Further, the very first sentence of the article, saying an organelle "is separately enclosed within its own lipid membrane" has to be modified. Some of the information in the new History and Terminology section shows these statements are way too strong. There are plenty of current usages of the term for non-membrane-enclosed structures. For instance, I have a 1998 book in front of me by Lynn Margulis which says early on, "Any visible structure inside a cell is an organelle." Google locomotion organelle and there are many scientific hits.

On the other hand, I'm sure some people are led to believe only membrane-enclosed structures can be organelles. For example, take Alberts et al. 4th edition (2002), a 1450-page mol bio college text. In the main text, the word is only used for membrane-enclosed structures (without regard to DNA), but the phrasing does not rule out other usages for organelle. However, the Glossary appendix, perhaps prepared by junior staff, defines organelle as "membrane-enclosed compartment in a eucaryotic cell that has a distinct structure, macromolecular composition, and function."

The W. article needs to make clear that the word is at times applied to non-membrane-enclosed structures since this is fact a long-established usage. I may do some rewriting of this stuff soonish if no substantial objections show up.

-R. S. Shaw 00:33, 5 November 2007 (UTC)

If you get around to the rewriting you may also want to have a look at a paper that suggests that Centrosomes have an RNA Genome: Alliegro, Mark C.; Mary Anne Alliegro and Robert E. Palazzo (June 13, 2006). "Centrosome-associated RNA in surf clam oocytes". Proc. Nat. Acad. Sci. USA 103 (24): 9034-9038. doi:10.1073/pnas.0602859103. . Maybe they are semiautonomous after all... --Dietzel65 23:20, 9 November 2007 (UTC)
Does the fact that their cnRNAs do not show sequence similarity to RNAs from most other organisms with centrosomes suggest that these are not likely to be more than some kind of molecular fossil? Could a reverse transcriptase provide enough genetic stability for an autonomous genetic component of an organelle? --JWSchmidt 01:31, 10 November 2007 (UTC)
Well, it could be that this centrosomal RNA is homologous to centrosomal RNAs in other Organisms which is just not yet discovered. I would assume that the group who has published the article is working on that right now. If there is more to it than an obscure finding in an obscure organism, we should see more articles about it in the upcoming years. Concerning the reverse transcriptase, I don't see why there would be a problem with stability? --Dietzel65 21:25, 14 November 2007 (UTC)
Reverse transcriptase is a rather error-prone polymerase. --JWSchmidt 04:29, 15 November 2007 (UTC)