Talk:Cell (biology)

The erroneous nature of this entire article

there are three domains of life & therefore three essential distinction in the variety of cells: eubacteria, archaebacteria & eukaryota. Traditionally, the three types present in the page are taught, however the definition has expanded, and there are many more cell types with distinct differences.

the intro, bad... scary bad... cells were first discovered? Cell was first coined as a term to discribe the cellular structure of cork, & further observed at a later date in collaboration, etc. Read up, use google.

Further Prokaryotic is an not only obsolete but its wrong. Prokaryotic suggests that the other two branches of life came BEFORE (PRO) Eukaryota & while this is a possibility, it isn't provable and remains philosophy and therefore you can't represent just one possibility but all known posibilities, etc. Thankfully, there are physical indicators used in the classification of cellular life today, DNA!!! we are decoding genetics & the continued use of old terminology is somewhat misleading and presents harm.

If you want to help correct this page, you can start here.

The Tree of Life: Tangled Roots and Sexy Shoots & here Scirus — Preceding unsigned comment added by Lawstubes (talk • contribs) 00:46, 23 July 2011 (UTC)

Wow I agree. This page is very badly written. I'll try and get to it later...--FUNKAMATIC ~talk 21:33, 4 September 2011 (UTC)

cells

I like what you wrote about cells — Preceding unsigned comment added by Lwash (talk • contribs) 19:45, 13 September 2011 (UTC)

Length of a cell

In the article it is stated that "The longest human cells are about 135 µm". I was under the impression that neurons held the title of the longest cell, given that a lower motor neurons extend from the spinal cord down to skeletal muscles in the lower limbs and ascending tracts enter the cord via the dorsal root and ascend to the medulla oblongata before synapsing with the second order sensory neuron. Can someone clarify this point, especially as the wiki page on the neuron states that some axons can be up to 1.5m long. — Preceding unsigned comment added by 194.176.105.132 (talk) 15:00, 15 September 2011 (UTC)

Flat contradiction in lede

Says longest cell is 135 um and then says there's one that is body length. Actually says this in same sentence ATM 72.228.177.92 (talk) 22:04, 2 November 2011 (UTC)

Since it was clear nonsense as it stood, and others complain above, redacted to what I think was meant. It's generally known there are long neurons from the brain to the extremities so the 135 um has to be just wrong so I deleted it. 72.228.177.92 (talk) 22:15, 2 November 2011 (UTC)

Looks like this had propagated thru the web, presumably from here, and in the same form, i.e. stating that there is a cell which is both "135 μm" and "the height of a person". 72.228.177.92 (talk) 22:22, 2 November 2011 (UTC)

There was the typical riot of Page ranked misinformation on this but I viewed the video from the Berkeley Anatomy course which cleared it up and redacted accordingly. Amazing. 72.228.177.92 (talk) 22:54, 2 November 2011 (UTC)

I am fairly certain that this part of the lede is incorrect: "...longest - pseudounipolar cells which reach from extremities, including the toes to the lower brain stem...". I believe the author has confused "brain stem" with "spinal cord". The sensory neuron that innervates the big toe, a pseudounipolar neuron, has its cell body in the dorsal root ganglion, which is located just outside the spinal cord (see the Wiki page on Pseudounipolar Cell). The key point is that there is no cell that runs all the way from your brain in your head all the way to your big toe. There are sensory axons in your big toe that run ~3 feet up to the dorsal root ganglion, and there are neurons in the spinal cord that project 2-3 to the brain, but there are no cells that make the whole toe-to-brain trip alone. In general I really like this Cell page though. Thanks for all your hard work. Bourgeb (talk) 00:37, 11 November 2011 (UTC)

I'll be happy to change brain stem to spinal cord, what you say makes sense, but need a source, the one given says brain and head, and as it's a video so the speaker, who takes a very simplistic approach, reinforces the point by pointing to her head and mentioning a whole body length. May be dated info, even anatomy progresses, there are few finished fields of knowledge. 72.228.177.92 (talk) 16:45, 16 November 2011 (UTC)

Thank you for this feedback. It is a very good point that I should provide a ref or two on this. I did a little poking around and I found a page outside of wikipedia that says: "The longest axon in the human body stretches from the base of the spine to a muscle in the big toe. An axon on one of these motor neurons can be over a meter long": http://www.psywww.com/intropsych/ch02_human_nervous_system/neurons.html . Also, the wiki page for "axon" says: "The longest axons in the human body, for example, are those of the sciatic nerve, which run from the base of the spine to the big toe of each foot". The "Pseudounipolar neuron" wiki page also says "one branch runs to the periphery and the other to the spinal cord". Further, my textbook "Biology" by N.A. Campbell, et al. (8th edition, copyright 2008, pp 1048, pub. Pearson/Benjamin Cummings) says "Axons are often much longer than dendrites, and some, such as those that reach from the spinal cord of a giraffe to the muscle cells in its feet, are over a meter long". These refs and others agree that the longest cell reaches from the *spinal cord* to the toe (and not from the brain stem to the toe). Sorry it took me a few days to get back to you on this. Cheers,

Bourgeb (talk) 05:35, 19 November 2011 (UTC)

bump

Bourgeb (talk) 01:34, 29 November 2011 (UTC)

Toward a 'Cell Death' Subsection

This page has sections on the life cycle of the cell including "Creation" and "Growth and Metabolism." The death section appears to be missing. It could contain a link to the page on apoptosis but also explain how poisons, viruses and anoxia actually cause the death of a cell, i.e., in the case of oxygen, what structures does affect, what happens to the physical parts of the cell during the dying process (and after death if it is part of a multicelluar organism). — Preceding unsigned comment added by 173.16.253.227 (talk) 03:21, 16 November 2011 (UTC)

Excellent idea, but maybe should have a larger scope, as there are immortal cells. Apoptosis, the mentioned insults, single cell organisms that reproduce by budding or other asexual means, and a range of other phenomena can be in it. 72.228.177.92 (talk) 17:24, 16 November 2011 (UTC)

Edit request on 29 December 2011

The article says " Humans contain about 100 trillion cells"

It should be changed to "Humans Contain 10 trillion cells"

Reference: In other related articles in wiki , Human Microbiome, it is stated that human body has 10 trillion cells and 100 trillion other micro-organisms

Humans cintain about 10 trillion cells

Kotappa (talk) 11:43, 29 December 2011 (UTC)

Done — Bility (talk) 17:12, 30 December 2011 (UTC)

Edit request on 11 January 2012

The largest cell, which is often debated, is WITHIN an ostrich egg, not the egg itself. The cell itself does not weigh 3.3 pounds.

184.184.116.220 (talk) 16:02, 11 January 2012 (UTC)

Not done: The source says the egg is the cell. Can you find a reliable source that says otherwise? — Bility (talk) 22:37, 11 January 2012 (UTC)

Largest, smallest, etc.

I don't get it. I don't think a list of the largest, smallest, longest, shortest, etc. cells in humans (and then animals) is important enough to include in the lead, and maybe not even in the article.

Think about it: The purpose of this article is to give someone a better understanding of the cell. How does it help you understand the cell to know that the largest cell is (or isn't) the ostrich egg cell?

There area great teachers who know how to select the few important ideas out of a mass of details and explain them well. I'm not one of them.

But Neil Campbell was, and his textbook has an introductory chapter on the cell. Campbell simply says that most plant and animal cells are between 1 and 100 µm and therefore are visible only under the microscope. Notice that he doesn't just give puzzling-looking numbers, he explains their significance.

When I have trouble figuring out how to explain something, I turn to Campbell and see how he did it. It's usually better to follow Campbell than for me to figure out how to explain it myself. Sometimes I can find a Nobel laureate who explains it even better than Campbell.

Is there anybody here who thinks he can explain biology better than Campbell? --Nbauman (talk) 07:29, 13 January 2012 (UTC)

I found the numbers (length of axon, diameter of smallest vs. largest cell types) quite useful, and I think it is a shame that you deleted this info from the lede. I don't think the page, as it was written, was trying to be better than Campbell's text. Rather, I believe that there is more than one way to give a nice overview of cellular biology. From my experience, the older folks in the field of molecular biology tend toward a more qualitative view, while the younger generation tends toward a more quantitative approach. I find the measurements (microns, meters, etc.) very useful in putting things into context. When teaching introductory biology, I find it particularly helpful to introduce the concept that a "cell" encompasses everything from a tiny, simple prokaryotic bacteria to the highly specialized, meter-long axon of a vertebrate sensory neuron. (This is pretty amazing, really.) I agree that the section you deleted wasn't all that well written--would you mind if I took a stab at revising it and re-posting the quantitative info? Or you can have a go at adding the info again if you prefer. I'd just really like to see the quantitative info included again, to provide context. Cheers, Bourgeb (talk) 05:43, 19 January 2012 (UTC)

Edit request on 22 January 2012

Ribosomes are large globular proteins, and they are not true organelles. They have long been mistaken to be an organelle of a cell. An organelle is supposed to be enclosed within a vesicle (such as lysosomes, peroxisomes, vacoules) that is made up of a linear lipid structure or a bilayer (nucleus). Ribosomes, on the other hand, is not an enclosed structure like lysosomes or vacuoles. They are either cytoplasmic proteins or proteins embedded on the rough endoplasmic reticulum. Ribosomes are not true organelles.

Biologist88 (talk) 18:51, 22 January 2012 (UTC)

N Not done,unsourced & unclear what you're asking, if you wanting this added to the ribsome section then I would say it's unnecessary as there is already an extensive article: Ribosome--Jac16888 ^Talk 14:32, 23 January 2012 (UTC)

Edit request on 23 January 2012

Another structure found outside the cell wall or cell membrane is the cilia. Cilia are fine, hair-like projections that enable free-living organisms such as protists to move around their environment. Cilia are also found in multicellular animals. They are found in the lining of the respiratory tract to move foreign materials away from the lungs and out to the external environment, acting like a brush or an escalator. They are also found lining the Fallopian tube of higher mammals. With a sweeping-like action, they maneuver the ovum (egg cell) towards the uterus.

Biologist88 (talk) 06:38, 23 January 2012 (UTC)

N Not done, same reason as above (Cilium)--Jac16888 ^Talk 14:33, 23 January 2012 (UTC)