# Cell size? **URL:** \ **Category:** Factual Questions\ **Created:** [August 14, 2022, 4:32pm UTC](https://boards.straightdope.com/t/cell-size/969645 "2022-08-14T16:32:16Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Post date:** [August 14, 2022, 10:49pm UTC](https://boards.straightdope.com/t/cell-size/969645/21 "2022-08-14T22:49:53Z")
> [@am77494](#): > > From what I understood, a woman who only has sons will essentially not pass on the mitochondria to the next generation. Also that sperms do not carry mitochondria. Think about that—if mothers didn’t pass mitochondria to sons, and fathers don’t pass mitochondria to anyone, _then males would not have mitochondria_. (Hint-males have mitochondria.) ---
**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Post date:** [August 14, 2022, 11:01pm UTC](https://boards.straightdope.com/t/cell-size/969645/22 "2022-08-14T23:01:37Z")
> [@am77494](#): > > It was pointed out that that mitochondria in a cell’s nucleus did not share the cell’s DNA, and most (some cells do not have mitochondria) cells are in a symbiotic relationship with mitochondria. Also, mitochondria are not found in the cellular nucleus, and the number of eukaryotic organisms currently known to have no mitochordria is [one](https://www.science.org/content/article/first-eukaryotes-found-without-normal-cellular-power-supply). ---
**Author:** ![am77494](https://avatars.discourse-cdn.com/v4/letter/a/d2c977/32.png) [@am77494](https://boards.straightdope.com/u/am77494)\ **Post date:** [August 15, 2022, 12:04am UTC](https://boards.straightdope.com/t/cell-size/969645/23 "2022-08-15T00:04:22Z")
> [@Darren\_Garrison](#): > > Think about that—if mothers didn’t pass mitochondria to sons, and fathers don’t pass mitochondria to anyone, _then males would not have mitochondria_. > > (Hint-males have mitochondria.) > [@Darren\_Garrison](#): > > Also, mitochondria are not found in the cellular nucleus, and the number of eukaryotic organisms currently known to have no mitochordria is [one](https://www.science.org/content/article/first-eukaryotes-found-without-normal-cellular-power-supply). Both are consistent with my understanding and what I have been saying too. ---
**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Post date:** [August 15, 2022, 12:51am UTC](https://boards.straightdope.com/t/cell-size/969645/24 "2022-08-15T00:51:45Z")
> [@am77494](#): > > Both are consistent with my understanding To be blunt, your understanding—isn’t. ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [August 15, 2022, 12:53am UTC](https://boards.straightdope.com/t/cell-size/969645/25 "2022-08-15T00:53:33Z")
> [@am77494](#): > > From what I understood, a woman who only has sons will essentially not pass on the mitochondria to the next generation. Also that sperms do not carry mitochondria. “Next” as in her grandchildren’s generation. Her son(s) have her mDNA. They however will not pass it on to their children (as you note, the sperm has no mDNA and the next generation of sons and daughters will get their mDNA from their mother.) Hence mDNA traces mother to daughter to … however many greats granddaughter in unbroken female line. Males are mDNA dead ends. And Y DNA is only passed father to son and on. But neither the Y chromosome or the mitochondria are organisms. ---
**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Post date:** [August 15, 2022, 12:57am UTC](https://boards.straightdope.com/t/cell-size/969645/26 "2022-08-15T00:57:25Z")
> [@DSeid](#): > > Males are mDNA dead ends. Well, _mostly_. > **[Paternal mtDNA transmission](https://en.wikipedia.org/wiki/Paternal_mtDNA_transmission)** > > In genetics, paternal mtDNA transmission and paternal mtDNA inheritance refer to the incidence of mitochondrial DNA (mtDNA) being passed from a father to his offspring. Paternal mtDNA inheritance is observed in a small proportion of species; in general, mtDNA is passed unchanged from a mother to her offspring, making it an example of non-Mendelian inheritance. In contrast, mtDNA transmission from both parents occurs regularly in certain bivalves. > Paternal mtDNA inheritance in animals varies. ... ---
**Author:** ![Riemann](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/riemann/32/3133_2.png) [@Riemann](https://boards.straightdope.com/u/Riemann)\ **Post date:** [August 15, 2022, 1:04am UTC](https://boards.straightdope.com/t/cell-size/969645/27 "2022-08-15T01:04:54Z")
> [@am77494](#): > > But is it accurate to say that the mitochondria is the same organism as the cell ? Yes, it is now indisputably part of the cell, an organelle. The existence of mitochondrial DNA and its pattern of inheritance does not imply that a mitochondrion is _still_ an independent organism. _Mycoplasma genitalium_ has 525 genes, the fewest of any known organism. Human mitochondria have 37. If something has no possible independent existence, there is no sensible way that you can consider it to be a separate organism. I think you have misconstrued explanations of the endosymbiotic theory that the evolutionary _origin_ of mitochondria in the long distant past was the engulfment of independent organisms. It took a long time for the endosymbiotic theory to be proposed and even longer for it to be widely accepted (and not universally so even now). That would not have been the case if they were _still_ independent organisms living inside other cells. Most of the original endosymbiont’s DNA is now part of the nuclear genome. Another very large chunk of your genome came from ancient viruses. These origins do not imply that a cell _still_ contains multiple separate entities, any more than the fact that half of your nuclear DNA came from your mother and half from your father implies implies the existence of two separate entities. ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [August 15, 2022, 1:10am UTC](https://boards.straightdope.com/t/cell-size/969645/28 "2022-08-15T01:10:03Z")
Interesting that there are some species that break the general pattern and that there is some sense about whether or not a few mitochondria from dads might slip in as the sperm is not absolutely devoid of mitochondria after all. But for general understanding purposes @am77494’s understanding about a female with only sons being a dead end for her mtDNA was pretty much right and should be recognized as such. It WOULD be interesting to have mitochondria that could transmit like viruses… ---
**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Post date:** [August 15, 2022, 1:12am UTC](https://boards.straightdope.com/t/cell-size/969645/29 "2022-08-15T01:12:15Z")
> [@DSeid](#): > > But for general understanding purposes @am77494’s understanding about a female with only sons being a dead end for her mtDNA was pretty much right and should be recognized as such. I read that as saying females do not pass on mitochondria to their own sons. ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [August 15, 2022, 1:22am UTC](https://boards.straightdope.com/t/cell-size/969645/30 "2022-08-15T01:22:04Z")
Hence the need to clarify what “next generation” means for the statement to be accurate. ---
**Author:** ![Riemann](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/riemann/32/3133_2.png) [@Riemann](https://boards.straightdope.com/u/Riemann)\ **Post date:** [August 15, 2022, 1:30am UTC](https://boards.straightdope.com/t/cell-size/969645/31 "2022-08-15T01:30:29Z")
> [@am77494](#): > > So a mitochondrial “DNA line” can go extinct while the main cell keeps going on. Is this correct ? The Y chromosome has a similar unusual pattern of inheritance, being passed solely down the male line. And it’s also worth nothing that _any_ allele in your nuclear genome can “go extinct” while the rest of the genome keeps going. If you have one child, half of your DNA is not inhertied by anyone, and if that contains any unique allele, that allele “goes extinct” when you die. So none of these patterns of inheritance are determinants of whether something should be considered a separate organism. ---
**Author:** ![Terminus\_Est](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/terminus_est/32/3087_2.png) [@Terminus\_Est](https://boards.straightdope.com/u/Terminus_Est)\ **Post date:** [August 15, 2022, 3:21am UTC](https://boards.straightdope.com/t/cell-size/969645/32 "2022-08-15T03:21:35Z")
> [@am77494](#): > > Also that sperms do not carry mitochondria. Spermatozoa contain 50-75 mitochondria. [Spermatozoon and mitochondrial DNA - PMC](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5904680/#:~:text=THE%20SPERMATOZOON%20CONTAINS%20approximately%2050,of%20mitochondria%20in%20its%20midpiece.&text=The%20structure%20and%20function%20of,the%20movement%20of%20the%20sperm). > [@](#): > > In eukaryotic cells, mitochondria are the major site of ATP production, which is achieved through the electron‐transport chain and oxidative phosphorylation, according to the energy demand. Mitochondria contain their own genome (mitochondrial DNA, mtDNA) on which a limited number of genes are encoded. In the human sperm, mitochondria helically wrap the midpiece of the tail and supply the energy for the driving force of motility. While various mutations in mtDNA in somatic cells are found to be associated with a wide spectrum of diseases, it is also reported that the abnormal mtDNA causes astenozoospermia and male infertility. At fertilization, the paternal mitochondria and mtDNA are rapidly degraded early in embryogenesis, thus, only maternal mtDNA is transmitted to the descendant. We briefly review here the basic characteristics of mtDNA and its maternal transmission during fertilization, as well as male infertility. (Reprod Med Biol 2002; **1** : 41–47) ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [August 15, 2022, 3:07pm UTC](https://boards.straightdope.com/t/cell-size/969645/33 "2022-08-15T15:07:08Z")
As noted by @Darren_Garrison previously. (Seriously people, and also looking at you @Riemann, you may want to consider reading others’ contributions…) And again for purposes up through undergraduate and even medical school biology, and certainly for the questions of the OP, the fact is that sperm have virtually no mitochondria, with exception of a few species, such as bivalve mollusks, paternal contribution to offspring mtDNA can be approximated as zero. I had professors like this. So interested in the rare exceptions and graduate level arcana that they could not explain the basics worth shit. ---
**Author:** ![DesertDog](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/desertdog/32/11503_2.png) [@DesertDog](https://boards.straightdope.com/u/DesertDog)\ **Post date:** [August 15, 2022, 3:11pm UTC](https://boards.straightdope.com/t/cell-size/969645/34 "2022-08-15T15:11:19Z")
> [@gnoitall](#): > > The human ovum is about 1mm, large enought to see with the naked eye. Yet is is fertilized – I guess that’s the term – by a sperm cell, one of the smallest human cells there are. I understand the logistical reasons for this factoid but find it amusing nevertheless. ---
**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Post date:** [August 15, 2022, 6:15pm UTC](https://boards.straightdope.com/t/cell-size/969645/35 "2022-08-15T18:15:31Z")
> [@DSeid](#): > > that sperm have virtually no mitochondria Spermatazoa have plenty of mitochondria for their size and structure (which is almost entirely nucleus and flagellum). Spermatazoa have an intense need for mitochondia because they need to burn lots of energy. They are like a spacecraft with fuel tanks strapped to the outside wherever they will fit. It is that they are mistly unused in the fertilized egg. (Feel free to dismiss that as an unimportant graduate-level detail if you wish.) [https://www.researchgate.net/figure/Diagram-showing-a-mature-human-spermatozoon-with-its-different-parts-Previously\_fig3\_259450365](https://www.researchgate.net/figure/Diagram-showing-a-mature-human-spermatozoon-with-its-different-parts-Previously_fig3_259450365) ---
**Author:** ![Great\_Antibob](https://avatars.discourse-cdn.com/v4/letter/g/e47c2d/32.png) [@Great\_Antibob](https://boards.straightdope.com/u/Great_Antibob)\ **Post date:** [August 15, 2022, 6:21pm UTC](https://boards.straightdope.com/t/cell-size/969645/36 "2022-08-15T18:21:45Z")
> [@gnoitall](#): > > A human neuron has a tiny body (100 microns), but its axon can be a meter long. (it’s super thin, so not naked-eye visible, but quite long.) Squid have [giant axons](https://en.wikipedia.org/wiki/Squid_giant_axon) that actually are naked-eye visible. I always found astonishing there were single cells large enough to be plainly visible ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [August 16, 2022, 12:46am UTC](https://boards.straightdope.com/t/cell-size/969645/37 "2022-08-16T00:46:35Z")
Yes it is that they are in most species nearly always completely unused. And that its 50 to 75 mitochondria, whatever their fate, are entering an ovum which, in the human case, has 100,000 to 600,000 mitochondria. (Liver cells have only a thousand or so.) ---
**Author:** ![Terminus\_Est](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/terminus_est/32/3087_2.png) [@Terminus\_Est](https://boards.straightdope.com/u/Terminus_Est)\ **Post date:** [August 16, 2022, 12:58am UTC](https://boards.straightdope.com/t/cell-size/969645/38 "2022-08-16T00:58:28Z")
I guess we’re not supposed to contribute here. @DSeid has spoken. ---
**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\ **Post date:** [August 16, 2022, 2:30am UTC](https://boards.straightdope.com/t/cell-size/969645/39 "2022-08-16T02:30:44Z")
**Moderator Note** > [@DSeid](#): > > I had professors like this. So interested in the rare exceptions and graduate level arcana that they could not explain the basics worth shit. Saying that everyone here can’t explain the basics worth shit is an insult directed at other users. If something isn’t explained worth shit, just correct the explanation. Don’t go on an all out attack on everyone in the thread. > [@Terminus\_Est](#): > > I guess we’re not supposed to contribute here. @DSeid has spoken If you want to be snarky and have a go at another user, you know where the Pit is. This is FQ, not the Pit. Post accordingly. ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [August 16, 2022, 2:33am UTC](https://boards.straightdope.com/t/cell-size/969645/40 "2022-08-16T02:33:06Z")
I apologize for the allusion to my professors who were so caught up in advanced stuff that they were shit at teaching the basics, if such offended. Its intent was not to insult, more a story about the problems of not addressing the room, albeit I can see how it may have been read as such. And I stand by the point. Comments like “your understanding—isn’t.” when the understanding as expressed is pretty much on target for a generally well educated person, should be corrected. For general understanding purposes sperm can be thought of as not having any significant to no mitochondrial contribution to future generations, as the standard understanding, other than for a few species. As to question regarding mitochondria as individual organisms … with other cells as their niche in an obligate symbiotic relationship … we don’t consider as such but I am not sure that @Riemann’s explanation of why quite suffices. > [@Riemann](#): > > If something has no possible independent existence, there is no sensible way that you can consider it to be a separate organism. There are obligate symbiotic relationships in which both are considered organisms in their own right but have co-evolved to the point that neither could survive without the other. Lichen as the obvious case. Viruses and their dependence on host cells to reproduce at least have a debate regarding their status as living. [Previous page](https://boards.straightdope.com/t/cell-size/969645.md?page=1) [Next page](https://boards.straightdope.com/t/cell-size/969645.md?page=3)