I studied an BSc in genetics and none of our lectures or textbooks presented mitochondria any differently from the classic bean shape they introduce in school. This is surely old news to folks who specialise in mitochondria, but it's easy to miss out on these fundamentals even if you've studied in a relevant area at degree level, because there's just so much to know in biology.
In fact, it's one of those fields where the more you learn, the more you realise we'll never reach a satisfactory understanding in our lifetime. You could chuck an endless supply of PhD students at every constituent domain for generations and still feel like you've scarcely scratched the surface of the many things there are to question.
jhedwards [3 hidden]5 mins ago
I'm reading an excellent book right now called Cells, Embryos and Evolution, in which one topic is the exploratory nature of certain biological processes. One of the processes described is the dynamic instability of microtubule growth.
Microtubules randomly grow and shrink from an anchor in the cell until they hit something that stabilizes them. Through their random growth they explore the cell, which means that processes depending on microtubules are robust against changes in size and shape of both the containing cell and the target object that needs the microtubules. The author explains that we still don't know how microtubules are stabilized, which I thought was fascinating.
Except that the book was written twenty years ago, and now we DO know how they are stabilized. It turns out that the author was the person who discovered microtubule instability, and since then we have not only figured out what stabilizes them, but have developed numerous cancer drugs based on those molecules: https://www.ncbi.nlm.nih.gov/books/NBK9932/#_A1831_
The progress of science is really incredible.
UltraSane [3 hidden]5 mins ago
Have we made much progress in understanding how the Kinetochore works?
epicureanideal [3 hidden]5 mins ago
> You could chuck an endless supply of PhD students at every constituent domain for generations and still feel like you've scarcely scratched the surface of the many things there are to question.
Sounds like a much better use of tax dollars than some other uses!
nialv7 [3 hidden]5 mins ago
> This is surely old news to folks who specialise in mitochondria
from Wiktionary:
> mitochondrion, Coined in German by Carl Benda in 1898, from Ancient Greek μίτος (mítos, “thread”) + χονδρίον (khondríon), diminutive of χόνδρος (khóndros, “grain, morsel”)
from Wikipedia article on Carl Benda:
> In an 1898 experiment using crystal violet as a specific stain, Benda first became aware of the existence of hundreds of these tiny bodies in the cytoplasm of eukaryotic cells and assumed that they reinforced the cell structure. Because of their tendency to form long chains, he coined the name mitochondria ("thread granules").
So yeah, I guess this is known ever since mitochondria was first discovered, definitely "old news". I can't understand why it is always depicted as bean-shaped.
Symbiote [3 hidden]5 mins ago
> I can't understand why it is always depicted as bean-shaped.
Do you disagree with the reason suggested in the article?
authorfly [3 hidden]5 mins ago
Not in genetics, but the kind of cursory neuroscience education that "AI" courses contain often goes no further than a sample cell at one point in the first weeks. I have found that the majority of AI graduates believe each cell contains one Mitochondria, even those who can explain the chemical processes behind associative memory and understand how there are multiple binding sites/receptors in most of those processes.
It goes to show how much simple diagrams influence understanding. The synaptic gap diagrams show multiple receptors and abstracted neurotransmitters, and gradients of multiple Ca or K ions. The neuron diagram shows one Mitochondria. That start influences their understanding for years.
jugg1es [3 hidden]5 mins ago
I have a BS in neurobiology from 2005 and the one lesson I took away and has been reinforced over and over again for me is that we know very little about biology. For example, epigenetics was only just getting talked about when I graduated. We are still only scratching the surface.
admissionsguy [3 hidden]5 mins ago
> the more you realise we'll never reach a satisfactory understanding in our lifetime
And thank you for posting the thank you because it was that that prompted me to bother to follow the link. I too think it was a great story, well told.
admissionsguy [3 hidden]5 mins ago
Fortunately, biology is broad but not particularly deep, so even undergrads routinely contribute to research. The story is a much better analogy for fundamental theoretical physics. Source: got some background in both, decided it didn't make sense to do theoretical physics before longevity is solved.
Anotheroneagain [3 hidden]5 mins ago
What books did Caesar read? In reality, books are not that useful. History doesn't show too much accumulation of knowledge over time - there is virtually no continuity between the bronze age and classical antiquity. Almost everything was lost, and built anew. Then it was all lost in another dark age. A few scraps remained.
In fact, civilisation rises and falls as brainpower rises and falls. There only was a long period of rise recently, but, it's been long over, and we now live off the scraps of what it produced.
ninalanyon [3 hidden]5 mins ago
Caesar almost certainly read classics of Greek philosophy and Roman literature.
But what does your comment have to do with books? There were none in the Bronze Age, nor for many centuries after it.
Anotheroneagain [3 hidden]5 mins ago
I was commenting on the absurdity of the story. It just doesn't seem to be how knowledge works. Nothing was discovered by such slow, long term accumulation of knowledge. Instead, knowledge seems to be discovered very quickly when the potential is there, and it decays and gets forgotten if the potential is lost.
For example, it was perfectly possible to be born when there was no powered flight at all, and live to see the moon landing.
And, while there are all the plans, and everything there was to write down about Saturn V, we can't do it again, as the human potential isn't there anymore. In fact, we can't even fly supersonic anymore.
Symbiote [3 hidden]5 mins ago
We certainly know how to do both those things (and military planes fly supersonic daily). That's because it's written down.
bentt [3 hidden]5 mins ago
Mitochondria are a descendant of early bacteria which infiltrated an Archaea cell, traded genes, and started replicating with it, forming a new organism about 1.5bn years ago.
The wild part is that all mitochondria are descended from that single event.
This was a rather controversial theory called Endosymbiosis and it was pioneered by Lynn Margulis. Now it is widely accepted.
The controvesial part is hypothesising nerve cells are endosymbiotically adapted fungus, and such like.
michalu [3 hidden]5 mins ago
[flagged]
ravenstine [3 hidden]5 mins ago
What would be an acceptable level of evidence that could convince you? Mitochondria even have their own DNA. The hypothesis that mitochondria were originally their own bacteria might not be confirmed via a lab experiment, but I'm not sure why you find it that silly of an idea.
comboy [3 hidden]5 mins ago
They don't kind of look like bacteria, there was a lot of gene sequencing and careful examination because it seemed like a very wild theory especially before we've really learned archaea. Quammen's "The Tangled Tree" has a nice writeup on on the process.
jr000 [3 hidden]5 mins ago
Thanks for reminding me why I don't read the comments on science articles on this site
captainclam [3 hidden]5 mins ago
I am sincerely curious about your thoughts on the origins of mitochondria, and how you came to feel so strongly about it.
melagonster [3 hidden]5 mins ago
When she proposed this hypothesis, there was not any molecule tool for this field.
devmor [3 hidden]5 mins ago
Please read more about a subject before making asinine generalizations. There were many steps between "imagined" and "accepted".
gcanyon [3 hidden]5 mins ago
Does anyone here have a sense of what time frame the video covers? Like, is that real-time and mitochondria are continuously mildly active? Is it vastly slowed down and mitochondria are ripping around in our cells like madmen? Is it vastly sped up and mitochondria are actually relatively static, slow movers?
tel [3 hidden]5 mins ago
Looking around, here's a post by the author on Twitter where he shows similar motion and states that the time-lapse is 10m at 1min/sec.
I'd guess it's a few minutes (5-10) compressed into the 10s video
tosser0001 [3 hidden]5 mins ago
Even the Wikipedia entry on them has the classic bean-shaped diagram. If they are not really like that, why did that become the standard representation? Have they always been know to exist in more network-like structures, and was that why there was initial resistance to seeing their origin in free-living prokaryotes?
comboy [3 hidden]5 mins ago
Cell diagrams are simplifications. Cells are not like your room with a few things inside. They are more like a decent city. In human cells you have hundreds to thousands of mitochondria.
UniverseHacker [3 hidden]5 mins ago
It was because they could only image a dead/fixed 2D cross section on an electron microscope. The 2D cross section of a vast interconnected network of tubes looks like disconnected small “beans.”
Mitochondria are so absurdly more complex and interesting than what is mostly taught in schools.
Awesome video!
kgc [3 hidden]5 mins ago
So each of our cells is a habitat for a network of wiggly energy-producing worms...
krige [3 hidden]5 mins ago
So it's fair to say that I'm pretty much worms that walk.
HP would be absolutely thrilled to know that. Or maybe terrified out of his mind. One of the two for sure.
justinator [3 hidden]5 mins ago
It's wormy things all the way down.
mrguyorama [3 hidden]5 mins ago
In the Halo universe, the "Hunter" enemy, the hulking shitheads covered in armor and blasting you with a fuel rod cannon and you have to shoot their orange weak spots, are actually colonies of little orange worms!
Also IIRC they work in pairs because they are mates. When you fight them you are killing a couple.
xarope [3 hidden]5 mins ago
more like wiggly other cells, which are essential as one of our main energy systems. It's funny when you dig into these, the terms are things like fermentation[0]... say what? My body is producing beer for energy?
Well mitochondria are important for cellular respiration where oxygen IS available, yeah?
hk__2 [3 hidden]5 mins ago
Are these wiggly other cells… a habitat for a network of wiggly other cells?
ravenstine [3 hidden]5 mins ago
> Powerhouses of the cell
Will we ever get away from this cliche? I loathe it because it's not only a cliche but I don't believe it actually helps the lay person understand the role of mitochondria. It's not completely inaccurate since they're effectively refining energy substrates (fat, glucose) into ATP by converting ADP in the TCA cycle; ATP becomes ADP again from energy expenditure and the cycle repeats, to oversimplify things. Are we adequately teaching people that mitochondria don't create or release (utilizable) energy? I kind of doubt it. But maybe I'm just annoyed from hearing that descriptor a bajillion times starting from middle school.
ndr42 [3 hidden]5 mins ago
> mitochondria don't create or release (utilizable) energy?
I'm confused: Where do my muscles (cross-bridge cycle) get the ATP from if not from mitochondria?
siva7 [3 hidden]5 mins ago
So beautiful and so sad to think about how much more interesting biology is than what we can teach from textbooks.
b3lvedere [3 hidden]5 mins ago
Ain't that the truth.
For instance: Before following Kurzgesagt - In a Nutshell and purchasing Mr. Philipp Dettmer's amazing book called Immune, i had never even heard of the complement system.
randoglando [3 hidden]5 mins ago
I found Immune a drag. Really enjoyed Cells At Work though!
b3lvedere [3 hidden]5 mins ago
The first two seasons were awesome, but i didn't like the Code Black spinoff that much.
justinator [3 hidden]5 mins ago
To think I've spent hours upon hours each week for years and year with the express goal of producing more of these in the muscle cells of my legs, and I call this novel goal "exercise".
efitz [3 hidden]5 mins ago
In the video, the mitochondria appeared to be motile. Are they?
This might be a sign of different schools of thought on the matter, but I'd alwys seen it referred to as endosymbiosis (as your article also notes).
jbotz [3 hidden]5 mins ago
Mitochondria are in endosymbiosis with eucaryotic cells. Symbiogenesis is the idea that eucaryotes came into being ("genesis") because some prior lifeforms joined in endosymbiosis.
JumpCrisscross [3 hidden]5 mins ago
> the idea that eucaryotes came into being ("genesis") because some prior lifeforms joined in endosymbiosis is the theory of symbiogenesis
Nope, endosymbiosis refers to the theory per se [1]. The 1966 article that "renewed interest in the long-dormant endosymbiont hypothesis of organelle origins" [2] referred to "the idea that the eukaryotic cell arose by a series of endosymbioses" [3]. The term symbiogenesis "was first introduced by the Russian Konstantin Sergeivich Mereschkovsky" in 1910.
Hypothesis: the school split is an artefact of symbiogenesis (the original term) being revisited during the Cold War. (It also seems symbiogenesis refers to the broader biological phenomenon of symbiosis. There was a symbiogenesis of the Nemo-anemone relationship. Nemo is not endosymbiotic to anemones.)
I had heard that cancer (in general) suppressed mitochondria in preference for anaerobic respiration, and that apoptosis commonly involves these organelles.
Not this cancer cell, it would seem.
woadwarrior01 [3 hidden]5 mins ago
You're most likely talking about Warburg effect[1].
Really sucks that antibiotics, especially bacteriocidal ones, appear to target mitochondria as if they were bacteria. This mistargetting causes sometimes severe and long-lasting side effects.
Which is unsurprising as any original self replicating organisms that showed up significantly later would be at a massive disadvantage, and early competition had billions of years to find a winner.
It’s worth remembering that evolution can end get stuck in suboptimal solutions because they still beat 99.999…% of the possibilities. Our blindspot is an issue but it showed up early enough that there’s been vast amounts of optimization based around that initial slightly sub optional feature.
yieldcrv [3 hidden]5 mins ago
Exhibit b.
Getting cancer, or specifically short telomeres, is a suboptimal evolutionary outcome that other some other mammals don’t have
But because the issue appears after we reproduce, it passes on
breck [3 hidden]5 mins ago
There are shockingly few images of mitochondria available online.
I'm currently mastering the same confocal fluorescence technique used in this image (but borrowing microscope time, as the scope costs >$250K), but also developing an at-home protocol using Janus Green that should cost less than $200.
In fact, it's one of those fields where the more you learn, the more you realise we'll never reach a satisfactory understanding in our lifetime. You could chuck an endless supply of PhD students at every constituent domain for generations and still feel like you've scarcely scratched the surface of the many things there are to question.
Microtubules randomly grow and shrink from an anchor in the cell until they hit something that stabilizes them. Through their random growth they explore the cell, which means that processes depending on microtubules are robust against changes in size and shape of both the containing cell and the target object that needs the microtubules. The author explains that we still don't know how microtubules are stabilized, which I thought was fascinating.
Except that the book was written twenty years ago, and now we DO know how they are stabilized. It turns out that the author was the person who discovered microtubule instability, and since then we have not only figured out what stabilizes them, but have developed numerous cancer drugs based on those molecules: https://www.ncbi.nlm.nih.gov/books/NBK9932/#_A1831_
The progress of science is really incredible.
Sounds like a much better use of tax dollars than some other uses!
from Wiktionary:
> mitochondrion, Coined in German by Carl Benda in 1898, from Ancient Greek μίτος (mítos, “thread”) + χονδρίον (khondríon), diminutive of χόνδρος (khóndros, “grain, morsel”)
from Wikipedia article on Carl Benda:
> In an 1898 experiment using crystal violet as a specific stain, Benda first became aware of the existence of hundreds of these tiny bodies in the cytoplasm of eukaryotic cells and assumed that they reinforced the cell structure. Because of their tendency to form long chains, he coined the name mitochondria ("thread granules").
So yeah, I guess this is known ever since mitochondria was first discovered, definitely "old news". I can't understand why it is always depicted as bean-shaped.
Do you disagree with the reason suggested in the article?
It goes to show how much simple diagrams influence understanding. The synaptic gap diagrams show multiple receptors and abstracted neurotransmitters, and gradients of multiple Ca or K ions. The neuron diagram shows one Mitochondria. That start influences their understanding for years.
Depends on how long you intend to live, really
https://slatestarcodex.com/2017/11/09/ars-longa-vita-brevis/
In fact, civilisation rises and falls as brainpower rises and falls. There only was a long period of rise recently, but, it's been long over, and we now live off the scraps of what it produced.
But what does your comment have to do with books? There were none in the Bronze Age, nor for many centuries after it.
For example, it was perfectly possible to be born when there was no powered flight at all, and live to see the moon landing. And, while there are all the plans, and everything there was to write down about Saturn V, we can't do it again, as the human potential isn't there anymore. In fact, we can't even fly supersonic anymore.
The wild part is that all mitochondria are descended from that single event.
This was a rather controversial theory called Endosymbiosis and it was pioneered by Lynn Margulis. Now it is widely accepted.
https://evolution.berkeley.edu/it-takes-teamwork-how-endosym...
https://x.com/mag2art/status/1385940103189745669
HP would be absolutely thrilled to know that. Or maybe terrified out of his mind. One of the two for sure.
Also IIRC they work in pairs because they are mates. When you fight them you are killing a couple.
[0] https://en.wikipedia.org/wiki/Fermentation
Will we ever get away from this cliche? I loathe it because it's not only a cliche but I don't believe it actually helps the lay person understand the role of mitochondria. It's not completely inaccurate since they're effectively refining energy substrates (fat, glucose) into ATP by converting ADP in the TCA cycle; ATP becomes ADP again from energy expenditure and the cycle repeats, to oversimplify things. Are we adequately teaching people that mitochondria don't create or release (utilizable) energy? I kind of doubt it. But maybe I'm just annoyed from hearing that descriptor a bajillion times starting from middle school.
I'm confused: Where do my muscles (cross-bridge cycle) get the ATP from if not from mitochondria?
For instance: Before following Kurzgesagt - In a Nutshell and purchasing Mr. Philipp Dettmer's amazing book called Immune, i had never even heard of the complement system.
Nope, endosymbiosis refers to the theory per se [1]. The 1966 article that "renewed interest in the long-dormant endosymbiont hypothesis of organelle origins" [2] referred to "the idea that the eukaryotic cell arose by a series of endosymbioses" [3]. The term symbiogenesis "was first introduced by the Russian Konstantin Sergeivich Mereschkovsky" in 1910.
Hypothesis: the school split is an artefact of symbiogenesis (the original term) being revisited during the Cold War. (It also seems symbiogenesis refers to the broader biological phenomenon of symbiosis. There was a symbiogenesis of the Nemo-anemone relationship. Nemo is not endosymbiotic to anemones.)
[1] https://evolution.berkeley.edu/it-takes-teamwork-how-endosym...
[2] https://pmc.ncbi.nlm.nih.gov/articles/PMC5426843/
[3] https://www.sciencedirect.com/science/article/pii/S002251931...
I had heard that cancer (in general) suppressed mitochondria in preference for anaerobic respiration, and that apoptosis commonly involves these organelles.
Not this cancer cell, it would seem.
[1]: https://en.wikipedia.org/wiki/Warburg_effect_(oncology)
https://en.wikipedia.org/wiki/Last_universal_common_ancestor
It’s worth remembering that evolution can end get stuck in suboptimal solutions because they still beat 99.999…% of the possibilities. Our blindspot is an issue but it showed up early enough that there’s been vast amounts of optimization based around that initial slightly sub optional feature.
Getting cancer, or specifically short telomeres, is a suboptimal evolutionary outcome that other some other mammals don’t have
But because the issue appears after we reproduce, it passes on
I started a project to increase that number by 1,000,000x: https://powerhouse.breckyunits.com/
I'm currently mastering the same confocal fluorescence technique used in this image (but borrowing microscope time, as the scope costs >$250K), but also developing an at-home protocol using Janus Green that should cost less than $200.