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!
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.
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?
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 human potential is there.
Somebody once claimed that the problem isn't that Johnny can't read, or that Johnny can't think, but that Johnny doesn't even know what thinking is, which is certainly a correct observation, but he incorrectly blamed it on the American schooling system.
But Johnny doesn't know what thinking is the same way that somebody who was born blind doesn't know what seeing is. You don't have to be taught to think, you just do. You figure things out, then you learn that others also know them. Or, sometimes that they don't, and know something completely different about the thing for whatever weird reason.
And such a person can live their entire life without thinking, convinced that being smart is simply about learning more and faster, and if they study hard, they will understand the topic on that deeper level like the old masters did, and perhaps they will also contribute something new one day.
But the thinking never comes.
Engineering does not—because of commerce, engineering can often even be actively hostile to transmitting knowledge. (I have a person next to me who knows how enterprise SSDs work and refuses to tell me more than “with great difficulty and ingenuity”.) Even without that, the task is difficult enough that without an explicit pressure to refine and preserve explanations that just won’t happen. There always will be people who value and enjoy that, but without a system in place to cultivate and reward them, there won’t arise that a kind of “collective knowledge” akin to collective immunity (or percolation) that the gaps can filled in.
This is actually a problem in the more engineering-oriented parts of science as well. For example, this is one of the problems with Hossenfelder’s suggestion that we stop building colliders: if we do that, in ten to fifteen years (a couple of generations of grad students) it’s fairly certain that we won’t be able to build them on anything like the current level. The US has already experienced this kind of institutional knowledge loss, in fact, with the shuttering of the SSC. So while I agree that they haven’t produced new—not just knowledge, but understanding in quite a while, we need to be really really sure before agreeing to lose this expertise.
And yet, look at physics. Like take a quantum field theory course (taken by what, probably a thousand, ten thousand students per year?) and trace the dependency chain. Even discounting all the backround knowledge we take for granted (e.g. “electricity exists”), the dependency chain is really really deep, probably something like a decade if you count the requisite high-school parts. (It includes some things that might seem unrelated on first glance but are in fact essential, like optics and thermodynamics.) That creates an actual problem in teaching it. And the subject itself is a year to two years deep at least before it becomes wide enough that you can mix and match topics, to say nothing of actual research.
I shudder to think what would happen if you tried to work through all of the materials science you encounter in an average first-world home (and all of the materials science, metallurgy, chemistry required to build that, etc.). An extremely fun project to contemplate, but I suspect too long for a human lifetime.
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...
"I'll be happy to give you a succinct summary of my views on this issue.
Molecular evidence (notably DNA sequence) absolutely confirms that the mitochondrial genome is of bacterial origin. The most compelling evidence in this regard comes from the sequence of the mitochondrial DNA (mtDNA) in a group of protists (eukaryotic, mostly single-celled, microbes) called jakobids. Key publications presenting the evidence and the arguments are:
Lang BF, Burger G, O'Kelly CJ, Cedergren R, Golding GB, Lemieux C, Sankoff D, Turmel M, Gray MW. 1997. An ancestral mitochondrial DNA resembling a eubacterial genome in miniature. Nature 387:493-497. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&d...
Burger G, Gray MW, Forget L, Lang BF. 2013. Strikingly bacteria-like and gene-rich mitochondrial genomes throughout jakobid protists. Genome Biol. Evol. 5:418-438. http://gbe.oxfordjournals.org/content/5/2/418.abstract
While sequence data firmly support the endosymbiont hypothesis insofar as the mitochondrial genome is concerned, the data also support the conclusion that the mitochondrion originated only once:
Gray MW, Burger G, Lang BF. 1999. Mitochondrial evolution. Science 283:1476-1481. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&d...
Of course, only a few essential mitochondrial proteins are encoded in mtDNA and synthesized inside mitochondria. The vast majority of the 2000+ proteins that make up a mitochondrion are encoded in the nuclear genome, synthesized in the cytoplasm, and imported into mitochondria. So, when we speak about the origin of the mitochondrion, we have to account not only for the mitochondrial genome (which is unquestionably of bacterial origin) as well as the mitochondrial proteome: the collection of proteins that constitute the complete organelle.
Accepting that the mitochondrion originated as a captive bacterium or bacteria-like entity, massive evolutionary restructuring has evidently occurred in the transition from endosymbiont to integrated organelle, including endosymbiotic gene transfer (movement of genes from the endosymbiont genome to the nuclear genome, with loss of the mtDNA copies), recruitment of host proteins, and acquisition of new proteins from outside the host via lateral gene transfer from other organisms. A very complicated business, made even more complicated by the recognition that subsequent mitochondrial evolution has taken different pathways in certain respects in different eukaryotic lineages.
While the CONCEPT of the endosymbiont hypothesis, as outlined above, is strongly supported and accepted, HOW this might have happened is still unclear, and may never be settled to everyone's satisfaction. Did the mitochondrion emerge early in the evolution of the eukaryotic cell through the union, by an unspecified mechanism, of a primitive archaeon (host) and primitive bacterium (endosymbiont), with this union actually being instrumental in the emergence of the eukaryotic cell? Or, did the mitochondrion emerge late, in an evolving archaeon host that already had some of the hallmarks of a typical eukaryotic cell, notably phagocytosis, the well-known mechanism by which modern eukaryotic cells take up bacteria for food? The pros and cons of these two (and many other) scenarios are still being hotly debated.
Hope this helps.
Cheers,
Michael W. Gray, PhD, LLD (h.c.), FRSC
Professor Emeritus
Department of Biochemistry and Molecular Biology
Dalhousie University
Halifax, Nova Scotia B3H 4R2, Canada."
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.
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)
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.
A coal power plant take a form stored energy which is relatively difficult to use because it has to be burnt with oxygen producing harmful waste products, and turns that energy into electricity which is easier to use in a variety of applications.
A mitochondria take a form of energy which is relatively difficult to use, sugars and fats, because they must be respired with oxygen producing harmful waste products, and turns that energy into ATP which is easier to use in a variety of applications.
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.
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.
thx.
