Talk:Cell (biology)

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To-do list for Cell (biology):

edit - history - watch - refresh
  • all cells have "traffic of vesicles." Is that true for prokaryotes?
  • multicellular organisms have cells that "do not generally survive" when separated. Can't most plants do that? Or sponges?
  • in the "cytoplasm" section, it says that all eukaryotes have cytoskeletons and implies that no prokaryotes do. Can someone confirm this?
  • is the description of processes like transcription and translation general enough to include all organisms, including prokaryotes?
  • Are the distinctions between prokaryotes and eukaryotes as clear as they should be? Is everything about the prokaryotes right?
  • can the line about "prokaryotic cells have three architectural regions..." be improved?
  • Is the prokaryotic cytoplasm more "granular" than in eukaryotes? Both kinds have ribosomes floating around...

Contents

[edit] Old discussion

Archaea are the oldest organisms existing.
Err - can we just get a reference for Archaea being progenitors of eukaryotes?
Some interesting references
Patrick Forterre, among which pour la science,22, 1998
CR Woese, Scientific American, 244, 94, 1981
J. Wiegel and M. Adams, Thermophiles and the Origin of Life, Taylor & Publisher, London, 1998
G.R. Block and J.A. Goode, Evolution of Hydrothermal Ecosystems on Earth. Ciba foundation, John Wiley and sons, 1996
The archeas are proposed not to be ancestors of euca, but on the same lign, and appearing sooner on this line
check out C.R. Woese and G.H. Olsen System Appl. Microbiology for the first proposition of the tree.
and N. Iwabe et al, Prob Natl. Acad. Sci. USA, 86, 9355, 1989 and P. Gogarten et al, Proc. Natl. Acad. Sci. USA, 86, 6661, 1989 for later improvment of it
For the proposition of euca resulting from the fusion of archea and bacteria, check out W.F. Dolittle.
might look also for a symposium on Thermophiles in 96. University of Georgia, Athens, Georgia, USA, with a lot of interesting things on thermophila and origin of life
user:anthere

What does it mean ? What evidence is available than they are older than bacteria ? (not to mention that this word has much meaning in evolutionary biology than people use to assume based on their false vision of evolution) --Taw

According to common theory, they are the ancestors of eukaryotes. By absorbing certain prokaryotes, they added new functions to themselves, becoming more complex in the process (endosymbiotic theory). Mitochondria and chloroplasts in eukaryotes, for example, are basically adapted bacteria.

They aren't any adapted bacteria. They were initially. Nowadays 95% of their structure is coded by cell nucleus, and they lost many other functions. --Taw

Today, several Archaea can only survive by adopting to extreme environments, e.g. geysers or black smokers. They can survive extreme pressure and heat, and can feed on methane or sulfur.

That's not that way. Some of them live in such environments, but many others don't.

And this sentence is sugesting that such an environment is in some way inferior to Eucaryotic environment. It would be as silly to say that fish can only survive by adopting to extreme (underwater) environment. --Taw

And it's also misleading in that some researchers theorize that those particular "extreme conditions" (hydrothermal vents) may be where life arose in the first place. In which case, non-Archaea life could only survive by adopting to extreme environments, eg. dry land and open ocean.


If i recall correctly the current picture of the tree of life (which is wobbly) has prokaryotes as the progenitors, with archaea and eukaryotes branching off at some later point. Of course, there's so much horizontal gene transfer amongst archaea/prokaryotes that it's really damn hard to say anything definitively... at any rate, I've NEVER heard that archaea came first, or that eukaryotes descended from archaea. Graft 04:53 Sep 27, 2002 (UTC)

no. It is not the current tree as accepted by most imho. It doesnot really state euca are descending from the archea. They don't appear to descend from procaryotes either. Most believe two lines appear from a common ancestor LUCA (well, the last common at least). Two lines separated. One leading to the bacteria, the other line followed a common way first, then gave the archea, later the eucaryotes. However, there are some biological inconsistencies with that proposition.
another proposition based not only on RNAr study but also on GC analysis seems to suggest the LUCA is leading to two branches, one leading toward eucaryotes, and the other leading to archea, which later gave the procaryotes. But that's only an hypothesis.
another proposition is that euca emerged from fusion of a bacteria and an archea.
maybe we should draw pictures of all the propositions...Did anybody tried to do that ???
user:anthere

I came here to complain about the article, and Taw wrote everything down already! Somebody needs to fix this. AxelBoldt 04:45 Sep 27, 2002 (UTC)


I came to check the original english article for somebody wanted to translate it in french, and I also came here to complain :-))

Anthere 00:06 Nov 25, 2002 (UTC)


I suspect this article is infelicitously named just as "mathematical group" was an exceedingly bad name for an article on its topic. The latter is now fortunately redirected to "group (mathematics)". No mathematician calls a group a "mathematical group", but it is within mathematics that the word "group" is used in the sense that that article contemplates. Would the same reasoning lead to the conclusion that this article should be redirected in the same way? (If so, the number of links to fix would be fairly large.) Michael Hardy 21:39 Mar 15, 2003 (UTC)


I agree that "Biological cell" is not what a biologist would name the page, but I think it makes very clear what is on the page, particularly for anyone who first goes to the "Cell" page. Why not put a brief statement near the top of the "Biological cell" page similar to what Michael Hardy wrote above? JWSchmidt 01:36 Mar 16, 2003 (UTC)

My vote would be for cell (biology). It's a little less natural to use in a sentence, but at the same time, I would expect people to use it more often regardless. Accidental links are important. There would indeed be a lot of pages to change - but surely by now someone capable has written a script for that? --Josh Grosse

Biological cell is more awkward to link to than cell (biology). You can just type cell (biology)|, but for biological cell, you have to do the full-blown alt text thing.
There are hundreds of links to this page under its current name, but if we don't want to change them, we really don't have to. People will find their way to the right page all the same. -Smack 02:14 4 Jul 2003 (UTC)
I fixed the cut and paste move. If there is no consensus about the new name it can be moved back, but I didn't want the history to split. Dori | Talk 16:06, Feb 23, 2004 (UTC)

Why the thumbnail near the top of the page? It's the same as the diagram lower down, but without the context that gives sense to its labels and explains what it's an example of. If we wanted to have pictures of various types of cells, I'm all for it, but I don't get this. -- Josh

I was looking for an image of another cell to use here. I think it's a good idea to have a thumbnail of the subject under discussion somewhere near the top, it helps orient (especially non-technical) readers to have an image in mind of the subject early in the article, and the way it is now, the image of the cell appears more than 50% of the way into the article. If we had another image of a cell, preferably an actual photograph or microscopy image, that would be even better. --Lexor|Talk 05:53, 3 Mar 2004 (UTC)

[edit] Billion

Article says: humans have an estimated 100,000 billion cells? What does that mean? Billion have two meanings and I am not sure which is it. Could someone, please, correct it to the format specified in the Wikipedia:Manual of Style (dates and numbers)? Or perhaps explain if 100,000 billion = 1017 or 1014? Przepla 18:28, 4 Nov 2004 (UTC)

Done: it should be 1014 (i.e. US billion). Lexor|Talk 12:15, Nov 5, 2004 (UTC)


[edit] The first cell

Deleted material moved here: The following paragraph basically says that a cell is better than free floating DNA and enzymes because a membrane keeps things together. It mentions lucky molecules and it admits that it is simple and doesn't really explain what it announced in the heading. The much better article origin of life should be properly summarized instead. In the meantime a reference should do the job.

If life is viewed from the point of view of replicators, that is DNA molecules in the organism, cells satisfy two fundamental conditions: protection from the outside environment and confinement of biochemical activity. The former condition is needed to maintain the fragile DNA chains stable in a varying and sometimes aggressive environment, and may have been the main reason for which cells evolved. The latter is fundamental for the evolution of biological complexity. If freely-floating DNA molecules that code for enzymes that are not enclosed into cells, the enzymes that advantage a given DNA molecule (for example, by producing nucleotides) will automatically advantage the neighbouring DNA molecules. This might be viewed as "parasitism by default". Therefore the selection pressure on DNA molecules will be much lower, since there is not a definitive advantage for the "lucky" DNA molecule that produces the better enzyme over the others: all molecules in a given neighbourhood are almost equally advantaged.

If all the DNA molecule is enclosed in a cell, then the enzymes coded from the molecule will be kept close to the DNA molecule itself. The DNA molecule will directly enjoy the benefits of the enzymes it codes, and not of others. This means other DNA molecules won't benefit from a positive mutation in a neighbouring molecule: this means that positive mutations give immediate and selective advantage to the replicator bearing it, and not on others. This is thought to have been the one of the main driving force of evolution of life as we know it. (Note. This is more a metaphor given for simplicity than complete accuracy, since the earliest molecules of life, probably up to the stage of cellular life, were most likely RNA molecules, acting both as replicators and enzymes: see RNA world hypothesis . But the core of the reasoning is the same.)

Biochemically, cell-like spheroids formed by proteinoids are observed by heating amino acids with phosphoric acid as a catalyst. They bear much of the basic features provided by cell membranes. Proteinoid-based protocells enclosing RNA molecules could (but not necessarily should) have been the first cellular life forms on Earth.

Re-inserted this into the article. Although it may need some work, it is pertinent to the article. Also the material herein is not developed in the origin of life article. You have made no effort to clean up this info or to add pertinent material either here or in origin of life. Wait for further discussion, add to origin of life, or edit for clarity here in this article. Don't just delete, I feel it belongs as an integral part of the Cell. I would also suggest that you register and get a user name, I prefer having a discussion with someone rather than an anon. IP address. -Vsmith 03:36, 9 Nov 2004 (UTC)

The paragraph raises more questions than it answers. It uses concepts as given it supposes to explain. Taking for example selection - a concept which applies to living organisms. It does not exist in chemistry. The content of origin of life is much more outspoken about these problems.
Please create a login, so we can more properly discuss this issue, it's difficult to leave messages etc. for IP addresses. I agree with most of your points about the paragraph, but it would be useful to use some of the text to add the pertinent material (rewritten) to either cell or origin of life, so it doesn't get completely lost. i.e. it makes sense for there to be a one paragraphy description of the development of membranes and why a membrane was such as step forward within the cell article (with more detailed info at origin of life). --Lexor|Talk 15:57, Nov 12, 2004 (UTC)

Re-inseting material deleted by anon user. No attempt has been made to either rewrite for this article or to include pertinent info in Origin of life. As stated previously, this material may need some fine tuning or revision, but the ideas are valid, thought provoking, and not thoroughly covered elsewhere. Cell origin is most definitely pertinent to this article. -Vsmith 03:27, 2 Dec 2004 (UTC)

[edit] cell formation

I just moved the article back to its original. Discuss before making a move of a large page with all those re-directs to fix. No, leave it here. Cell formation is not a good name anyway. Cell biology w/out the parens would be better, but if it is moved there is a lot of link changes to make. I vote to leave as is unless someone gives some very good reasons. Vsmith 21:36, 9 Feb 2005 (UTC)

[edit] Fact Check

While I was reading through the article, I fixed things that I knew were wrong, but I also found a few things that don't seem to fit with what I know about cells, where I was too unsure to change them. I thought maybe you'd know:

  • all cells have "traffic of vesicles." Is that true for prokaryotes?
  • multicellular organisms have cells that "do not generally survive" when separated. Can't most plants do that? Or sponges?
  • in the "cytoplasm" section, it says that all eukaryotes have cytoskeletons and implies that no prokaryotes do. Can someone confirm this?
  • is the description of processes like transcription and translation general enough to include all organisms, including prokaryotes?
  • Are the distinctions between prokaryotes and eukaryotes as clear as they should be? Is everything about the prokaryotes right?
  • can the line about "prokaryotic cells have three architectural regions..." be improved?
  • Is the prokaryotic cytoplasm more "granular" than in eukaryotes? Both kinds have ribosomes floating around...

I'll put up more questions when I finish the article. Thanks in advance for your help. Dave (talk) 12:01, Jun 17, 2005 (UTC)

To anwser the questions so far:

  • All organisms use vesicles to transport proteins etc from the ER to the membrane and other compartments
  • The single cells from MC organisms do not generally survive statement is right and wrong, no cells from a MC organism will survive if you take them out and stick them in a dish, most (all?) MC cells will proliferate from single cells if you give them the right cues but they won't make a new organism, plants (and mabye fungi, I need to do more reading on fungi) are the only organism that can regenerate a new multicellular organism from a single cell.
  • All cells have a cytoskeleton, its integral for cell division.
  • They key difference between prokaryotic and eukaryotic transcription and translation is that in eukaryotic systems transcription and translation occur sequentially whereas in prokaryotes transcription and translation occur simultaneously within the cell. This is probably the only distinction that needs to be made in a summary article like this.
  • this could be clearer:
Most of the functions of organelles, such as mitochondria, chloroplasts, and the Golgi apparatus, are taken over by the prokaryotic plasma membrane. Mabye could be: many of the fuctions performed by the oraganelles of eukaryotic cells occur on (across?) the plasma membrane of the prokaryote, for example, ATP regeneration and photosynthesis.
Not all bacteria have cell walls
  • The phrase architectural regions isn't helping with clarity, get rid of it and describe the parts of the prokaryotic cell simply.
  • I think that the granularity of the cytoplasm depends on the type of cell and the metablolic state of the cell, and isn't really correlated with prokaryotes vs. eukaryotes.

--nixie 05:51, 18 Jun 2005 (UTC)

Thanks for your help. Note to self: I still need to deal with the transcription one, the "this could be clearer" one, aand the "architectural regions" one. Dave (talk) 12:27, Jun 18, 2005 (UTC)

All organisms use vesicles to transport proteins etc from the ER to the membrane and other compartments. Prokaryotes don't have an ER. Josh Cherry 12:46, 18 Jun 2005 (UTC)

Should have been more careful there, but they do have vesicles to store lipds, usually called membrane vesicles; aquatic bacteria also have structures called gas vesicles (but they're more like a vacuole)--nixie 13:20, 18 Jun 2005 (UTC)

[edit] Cells evolved from bubbles on the shores of the primordial seas

I read recently a theory suggesting that the first cells evolved from the bubbles of crashing waves on the shores of the ancient ocean. If I can provide the source, and perhaps a more detailed account of the theory, would it be worth mentioning in the 'cell origins' section? - R Lee E (talk, contribs) 21:15, August 22, 2005 (UTC)

I referred to my source to gather further details, and have put together a rough summary in my own words. The book is called "The Cell: Evolution of the First Organism" by Joseph Panno, Ph.D. Here's what I've got so far:

....proteinoids are observed by heating amino acids with phosphoric acid as a catalyst. They bear much of the basic features provided by cell membranes. Proteinoid-based protocells enclosing RNA molecules could (but not necessarily should) have been the first cellular life forms on Earth.

Another theory holds that the turbulent shores of the ancient costal waters may have served as a mammoth labratory, aiding in the countless experiments necessary to bring about the first cell. Waves breaking on the shore create a delicate foam composed of bubbles. Winds sweeping across the ocean have a tendancy to drive things to shore, much like driftwood collecting on the beach. It is possible that organic molecules were concentrated on the shorelines in much the same way. Shallow coastal waters also tend to be warmer, further concentrating the molecules through evaporation. While bubbles comprised of mostly water tend to burst quickly, oily bubbles happen to be much more stable, lending more time to the particular bubble to perform these crucial experiments. The Phospholipid is a good example of a common oily compound prevalent in the prebiotic seas. Phospholipids can be constructed in ones mind as a hydrophilic head on one end, and a hydrophobic tail on the other. Phospholipids also possess an important characteristic, that is being able to link together to form either a monolayer, or a bilayer bubble membrane. A lipid monolayer bubble can only contain oil, and is therefore not conducive to harbouring water-soluble organic molecules. On the other hand, a lipid bilayer bubble [1] can contain water, and was a likely precursor to the modern cell membrane. If a protein came along that increased the integrity of its oily bubble, then that bubble had an advantage, and was placed at the top of the natural selection waiting list. Primitive reproduction can be envisioned when the bubbles burst, releasing the results of the experiment into the surrounding medium. Once enough of the 'right stuff' was released into the medium, the development of the first prokaryotes, eukaryotes, and multi-celluar organisms could be acheived. This theory is expanded upon in the book, "The Cell: Evolution of the First Organism" by Joseph Panno Ph.D.

Your contributions are welcome ofcourse. - R Lee E (talk, contribs) 07:36, August 24, 2005 (UTC)

It sounds quite speculative, but I'll let the other editors decide whether it merits inclusion. I've made some general language edits to improve NPOV, though.

Another theory holds that the turbulent shores of the ancient costal waters may have served as a mammoth labratory, aiding in the countless experiments necessary to bring about the first cell. Waves breaking on the shore create a delicate foam composed of bubbles. Winds sweeping across the ocean have a tendancy to drive things to shore. It is possible that organic molecules were concentrated on the shorelines in much the same way. Shallow coastal waters also tend to be warmer, further concentrating the molecules through evaporation. While bubbles comprised of mostly water tend to burst quickly, oily bubbles happen to be much more stable, lending more time to the particular bubble to perform these crucial experiments. The Phospholipid is an example of a common oily compound prevalent in the prebiotic seas. Phospholipids can be constructed in ones mind as a hydrophilic head on one end, and a hydrophobic tail on the other. Phospholipids also possess an important characteristic, that is being able to link together to form either a monolayer, or a bilayer bubble membrane. A lipid monolayer bubble can only contain oil, and is therefore not conducive to harbouring water-soluble organic molecules. On the other hand, a lipid bilayer bubble [2] can contain water, and was a likely precursor to the modern cell membrane. If a protein came along that increased the integrity of its oily bubble, then that bubble had an advantage, and was placed at the top of the natural selection waiting list. Primitive reproduction can be envisioned when the bubbles burst, releasing the results of the experiment into the surrounding medium.

--Ryan Delaney talk 18:08, 25 August 2005 (UTC)


[edit] Energ storing

what stores the energy in cells. If the mitochondria creats the energy where does it go to awate use. is it used otomaticaly or is it stored somewhere. This was unclear to me. If you can answer my question thak you. Oh and people stop conplaining.(69.154.246.64 04:06, 13 December 2005 (UTC)) Benerally, it is stored in the form of glicoe. When the energy is needed, glicose is used to produce ATP, and the ATP is used "power-up" some quemical reactions. while that, I think that ATP os free on the citoplasm, like the NaCl in a solution. I THINK that's how it work's, but I'm not shure. algumacoisaqq 13:27, 13 December 2005 (UTC)

This --> ATP is a link to the specific ATP article you want. There are some other "energy rich" chemicals that also act to store the chemical energy from mitochondria. Wikipedia needs a better article on bioenergetics. text book --JWSchmidt 13:53, 13 December 2005 (UTC)

[edit] what is the meaning of the word cell

[edit] Prokaryotes lack cytoskeleton

This was todo question. Can be confirmed from various sources, e.g. [3] [4] [5] [6] Lejean2000 13:11, 10 February 2006 (UTC)

Take a look at [7],[8]--JWSchmidt 13:46, 10 February 2006 (UTC)
I missed this. I didn't even suspect such findings. Here are more (downloadable) articles describing the functions of actin and tubulin homologues in bacteria. [9] [10] Lejean2000 15:53, 10 February 2006 (UTC)

We should make an effort to provide up-to-date references at Cytoskeleton#The prokaryotic cytoskeleton and related pages. --JWSchmidt 16:00, 10 February 2006 (UTC)

Most articles I found today are way too technical to be useful, at least for me. Anyway, I am very far outside my field of knowledge, so I'll keep any contributions I can offer in the discussion pages. I think we should keep links for specific proteins at their respective pages (FtsZ, MreB, etc...). Here is what I found interesting: [11], [12],[13], [14],[15], and a bit earlier article - [16] and Margolin, W. Themes and variations in prokaryotic cell division. Fems Microbiology Reviews, 2000 Oct, 24(4):531-48. There are actually more of those, as I got hooked on the subject. I hope someone is interested. Lejean2000 16:55, 10 February 2006 (UTC)


[edit] Table 2

Would somone who knows more biology than please check this table for accuracy. It has vacuoles in the animal cell section. I'm pretty sure they should be in the plant cell section. Theresa Knott | Taste the Korn 16:10, 23 February 2006 (UTC)

hi

  im caleb

budda

[edit] Image

--Snek01 21:40, 18 March 2006 (UTC)

[edit] The extracellular matrix

I think some description of how the cell works in the ECM should be added here, or at least a link to ECM. 128.139.226.37 15:48, 31 May 2006 (UTC)

[edit] Diseases of the cell?

I don't like this section. It only covers cancer, while arguably, most diseases are diseases of the cell... Extracellular parasites are the only exception that comes to mind at the moment. For example, any virus-mediated disease is a disease of the cell, as viruses replicate inside cells. Would anyone mourn this section's passing? Peter Z.Talk 21:21, 16 June 2006 (UTC)

Yes, but only because I've added a bit to it. :P Nah, I think that bacteriophages are the only disease category I can think of. Perhaps reinsert something about viruses generally in the section on reproduction?GiollaUidir 23:27, 18 June 2006 (UTC)

[edit] References!!!

For an article of this length and about a scientific subject there should be a mass of references; instead there's only one. Some work needed! Would it be useful to go through the article indicating useful points to insert them??GiollaUidir 23:12, 18 June 2006 (UTC)

Since its a very general article, I think it would be most appropriate to add a couple of textbooks and online resources as references. I don't think inline references are critical for most of the article. Peter Z.Talk 23:17, 18 June 2006 (UTC)
PS I see there are a couple of links to text books already. This is sufficient in my personal opinion. 23:22, 18 June 2006 (UTC)
Ok, just that there seem to be some debatable points in the article which a reference or two would clear up. (Maybe!)GiollaUidir 23:28, 18 June 2006 (UTC)
I'll have a good look... In my opinion this article should have no such points, unless they are really important. As a very general audience article it should contain only well established facts and views. Peter Z.Talk 23:38, 18 June 2006 (UTC)

[edit] Peer review

The peer review of this article is a little old and stale, so I'll post here that I posted there in case nobody's reading the peer review subpage anymore. Opabinia regalis 08:35, 1 July 2006 (UTC)

I am actually stll trying to follow it :) The reason it's gone stale is that noone has replied apart from Andy and his bot. Thank you for your comments, I'll get to work on them. Peter Z.Talk 08:51, 1 July 2006 (UTC)

[edit] Cells in the human body section

I have removed this section, as havng a whole section for one statistic that was already in the intro was pointless Jnb 11:17, 7 August 2006 (UTC)

[edit] Microbodies -> Vacuole

Somehow the German version of the picture below has no vacuole but calls it Microbody and 10 an 12 are mixed.

"Microbody -> Vacuole"
Enlarge
"Microbody -> Vacuole"

. I am no cell biologist, so what is correct now, or are both correct and have one missing?


your welcome to use this diagram instead. I can label it if you want. It has a vacuole over in the left hand side of the picture. Its a non-specific cell, e.g. it has visible centrioles and a chloroplast. It was drawn to replace that diagram above.

"Cell image"


[edit] Printable Version

dont know if tis is the right place to complain, but something is wrong with the printable version. the first part of the text in the printable version only fills the left half of the pages (or the bottom parts are to wide dont know). anyways it looks really weird when printed... thanks for help - 85.220.132.38 12:02, 28 October 2006 (UTC)