4 ms·

I've never really understood the story of mitochrondria. It's like "This cell absorbed another type of cell [ok so far] but then every future generation of this

I've never really understood the story of mitochrondria. It's like "This cell absorbed another type of cell [ok so far] but then every future generation of this cell includes the absorbed cell. [<-- How does that bit work?]"

deleted 3y ago
[deleted]
LordKeren 3y ago
Can you elaborate on the part that seems unintuitive? Eukaryotic cells have multiple copies of their mitochondria, not one. When the cell divides, the mitochondria (roughly) split between the two daughter cells then carry on
- Karawebnetwork 3y ago
  > Can you elaborate on the part that seems unintuitive? For me, the intuitive part is how mitochondria can be created by the body if it's an external structure that's been found. If I take a coin and put it in my pocket, my children don't have any coins at birth. They have to find one themselves. Why is it different for mitochondria?
  - myfavoritetings 3y ago
    Mitochondria are self replicating. When the cell splits some of the mitochondria are present in each new cell.
  - gadders 3y ago
    Yeah, this was how I was thinking as well. But to continue the analogy, it's more like you split yourself into two smaller "you"s, and in the process each new "you" gets half a coin in the pocket of each new "you".
    - LordKeren 3y ago
      To clarify, it would be more like you have a group of 10 coins and each of your offspring get 5, but grow back to having 10 during development
      - gadders 3y ago
        Yes, they carry on growing.
  - randomname93857 3y ago
    From what I've read, Each cell contains from dozens to a hundred+ mitochondrias. When cell splits then some mitos go to one child and some to another.
  - LordKeren 3y ago
    That’s because creation of new coins is external to your reproduction. Eukaryotic cells are not scavenging in the wild for new mitochondria; they control the replication of mitochondria within them, including how they are passed to offspring through reproduction An interesting thing about mitochondria too— we receive all of our mitochondria from our mother. So for every human, there is an unbroken line of direct mitochondrial ancestors leading all the way back to the first biologically unique Homo Sapian women
- gadders 3y ago
  From what you have said, I think my mental model for how life forms at the mammal-size level is wrong. The piece I was missing is that even for large organisms, new life is created by cells (eggs) already containing mitochondria dividing. New cells aren't created from scratch.
- dboreham 3y ago
  Not parent, but there's something missing that leads to the organism becoming stable between generations. Do the mitochondria independently reproduce and it just happens that you end up with neither too many nor too few of them, generation to generation?
  - anonymouskimmer 3y ago
    https://en.wikipedia.org/wiki/Human_mitochondrial_genetics#Replication,_repair,_transcription,_and_translation https://en.wikipedia.org/wiki/Human_mitochondrial_genetics#R... : Mitochondrial replication is controlled by nuclear genes and is specifically suited to make as many mitochondria as that particular cell needs at the time. : Each human cell contains approximately 100 mitochondria : The amount of mitochondria per cell also varies by cell type : Egg cell: Mature metaphase II egg cells can contain 100,000 mitochondria (so when it comes to passing down mitochondria to descendants, eukaryotes don't fool around)
  - LordKeren 3y ago
    Eukaryotic cells control the replication of mitochondria through signaling pathways
favoritecolor 3y ago
People used to think it was really rare -- until someone actually recreated it in the lab[0]. In this paper, the researchers created a strain of bacteria (prokaryote) that would only survive if engulfed by modified strain of yeast (eukaryote) that would depend on engulfing said bacteria. And shockingly, it worked! The engineered bacteria replaced the natural mitochondria in the yeast. Wild. But I guess to answer your question more directly, the cells that don't have the mitochondria would more likely die, because they don't have the fitness advantage. [0] https://pubmed.ncbi.nlm.nih.gov/30373839/ https://pubmed.ncbi.nlm.nih.gov/30373839/
__MatrixMan__ 3y ago
If you can reliably hop the turnstyle and ride the subway for free, then managing to place a friend in two separate cars to be on either side of a planned decoupling doesn't seem like too much of a stretch. It would be even more miraculous if the cell managed to relate interlopers to just one side for the event. Although you're kind of getting away from cell fission at that point: that's more like birth.
code_biologist 3y ago
If you're interested in biology, I highly highly recommend the book "Power, Sex, Suicide: Mitochondria and the Meaning of Life" by Nick Lane. It explains the original endosymbiosis and evolutionary process that went on in both bacteria, all the cool stuff that only eukaryotes can do, and why. Goodreads: https://www.goodreads.com/book/show/39001.Power_Sex_Suicide https://www.goodreads.com/book/show/39001.Power_Sex_Suicide

deleted 3y ago

[deleted]

LordKeren 3y ago

Can you elaborate on the part that seems unintuitive? Eukaryotic cells have multiple copies of their mitochondria, not one. When the cell divides, the mitochondria (roughly) split between the two daughter cells then carry on

Karawebnetwork 3y ago
> Can you elaborate on the part that seems unintuitive? For me, the intuitive part is how mitochondria can be created by the body if it's an external structure that's been found. If I take a coin and put it in my pocket, my children don't have any coins at birth. They have to find one themselves. Why is it different for mitochondria?
- myfavoritetings 3y ago
  Mitochondria are self replicating. When the cell splits some of the mitochondria are present in each new cell.
- gadders 3y ago
  Yeah, this was how I was thinking as well. But to continue the analogy, it's more like you split yourself into two smaller "you"s, and in the process each new "you" gets half a coin in the pocket of each new "you".
  - LordKeren 3y ago
    To clarify, it would be more like you have a group of 10 coins and each of your offspring get 5, but grow back to having 10 during development
    - gadders 3y ago
      Yes, they carry on growing.
- randomname93857 3y ago
  From what I've read, Each cell contains from dozens to a hundred+ mitochondrias. When cell splits then some mitos go to one child and some to another.
- LordKeren 3y ago
  That’s because creation of new coins is external to your reproduction. Eukaryotic cells are not scavenging in the wild for new mitochondria; they control the replication of mitochondria within them, including how they are passed to offspring through reproduction An interesting thing about mitochondria too— we receive all of our mitochondria from our mother. So for every human, there is an unbroken line of direct mitochondrial ancestors leading all the way back to the first biologically unique Homo Sapian women
gadders 3y ago
From what you have said, I think my mental model for how life forms at the mammal-size level is wrong. The piece I was missing is that even for large organisms, new life is created by cells (eggs) already containing mitochondria dividing. New cells aren't created from scratch.
dboreham 3y ago
Not parent, but there's something missing that leads to the organism becoming stable between generations. Do the mitochondria independently reproduce and it just happens that you end up with neither too many nor too few of them, generation to generation?
- anonymouskimmer 3y ago
  https://en.wikipedia.org/wiki/Human_mitochondrial_genetics#Replication,_repair,_transcription,_and_translation https://en.wikipedia.org/wiki/Human_mitochondrial_genetics#R... : Mitochondrial replication is controlled by nuclear genes and is specifically suited to make as many mitochondria as that particular cell needs at the time. : Each human cell contains approximately 100 mitochondria : The amount of mitochondria per cell also varies by cell type : Egg cell: Mature metaphase II egg cells can contain 100,000 mitochondria (so when it comes to passing down mitochondria to descendants, eukaryotes don't fool around)
- LordKeren 3y ago
  Eukaryotic cells control the replication of mitochondria through signaling pathways

favoritecolor 3y ago

People used to think it was really rare -- until someone actually recreated it in the lab[0]. In this paper, the researchers created a strain of bacteria (prokaryote) that would only survive if engulfed by modified strain of yeast (eukaryote) that would depend on engulfing said bacteria. And shockingly, it worked! The engineered bacteria replaced the natural mitochondria in the yeast. Wild. But I guess to answer your question more directly, the cells that don't have the mitochondria would more likely die, because they don't have the fitness advantage. [0] https://pubmed.ncbi.nlm.nih.gov/30373839/ https://pubmed.ncbi.nlm.nih.gov/30373839/

__MatrixMan__ 3y ago

If you can reliably hop the turnstyle and ride the subway for free, then managing to place a friend in two separate cars to be on either side of a planned decoupling doesn't seem like too much of a stretch. It would be even more miraculous if the cell managed to relate interlopers to just one side for the event. Although you're kind of getting away from cell fission at that point: that's more like birth.

code_biologist 3y ago

If you're interested in biology, I highly highly recommend the book "Power, Sex, Suicide: Mitochondria and the Meaning of Life" by Nick Lane. It explains the original endosymbiosis and evolutionary process that went on in both bacteria, all the cool stuff that only eukaryotes can do, and why. Goodreads: https://www.goodreads.com/book/show/39001.Power_Sex_Suicide https://www.goodreads.com/book/show/39001.Power_Sex_Suicide