[HN Gopher] Mitochondria Are Alive
       ___________________________________________________________________
        
       Mitochondria Are Alive
        
       Author : mailyk
       Score  : 335 points
       Date   : 2024-11-08 17:39 UTC (5 hours ago)
        
 (HTM) web link (www.asimov.press)
 (TXT) w3m dump (www.asimov.press)
        
       | kranke155 wrote:
       | I wonder what mitochondria dream about. Do they have elections?
       | Politics? Their own understanding of the universe, that somehow
       | ends on the skin surface?
        
         | addicted wrote:
         | Alive != sentient
        
           | tkzed49 wrote:
           | debatable
        
             | snorin wrote:
             | even "dead=!sentient" remains debatable
        
         | berbec wrote:
         | > I wonder what mitochondria dream about.
         | 
         | ATP sheep.
        
       | Teever wrote:
       | As a layman I'm kind of baffled by the enduring pop-sci interest
       | in mitochondria.
       | 
       | To me the far more interesting organelle is the ribosome. This
       | elegant self-replicating machine that is highly conserved across
       | lifeforms is fascinating and much closer to the origin of life
       | than mitochondria.
       | 
       | How did ribosomes evolve? Are the ribosomes that we see in modern
       | organisms the first design that did evolve? Why are they highly
       | conserved?
       | 
       | Are ribosomes alive as well?
        
         | adastra22 wrote:
         | The mitochondria and their dysfunction are likely the basis of
         | most aspects of aging, so an intensive interest in them is
         | understandable.
        
           | GordonS wrote:
           | Also thought to be involved with Chronic Fatigue Syndrome
           | (CFS/ME).
        
           | Teever wrote:
           | That's a debatable statement and it doesn't explain the
           | public appeal of mitochondria over ribosomes that predates
           | recent research on the relationship between mitochondria and
           | aging.
        
             | adastra22 wrote:
             | Why are you insisting on this comparison to ribosomes?
             | They're both interesting.
        
               | rbanffy wrote:
               | All organelles are valid. This is not a competition. Both
               | mitochondria and ribosomes are cool in different ways.
        
               | Teever wrote:
               | I'm just wondering why we always see pop-sci mitochondria
               | content but no ribosome videos.
               | 
               | I think it's the catchy nickname "powerhouse of the
               | cell."
               | 
               | Ribosomes don't have a catch nickname so they get a lot
               | less content produced about them.
               | 
               | If I was a highschool biology teacher I'd probably call
               | them "The assembly line of life." That would stick in
               | people's minds I bet.
        
               | olddustytrail wrote:
               | Then go ahead. Make those videos. Sell that vision.
               | There's no one stopping you except you.
        
               | Teever wrote:
               | I don't get the adversarial tone about this.
               | 
               | My intention in asking the question isn't to create
               | animosity. I'm just curious why the thing that I've
               | observed is a thing.
        
           | lostemptations5 wrote:
           | It's interesting, could you expand on thus?
        
         | dist-epoch wrote:
         | Todays ribosomes are not alive by any definition.
         | 
         | But it's possbile they are descendants of some self-replicating
         | self-catalyzed RNA chain (RNA world)
        
         | jamiek88 wrote:
         | They are both very interesting. I don't think there's
         | necessarily interest in one are the expense of another?
        
         | francisofascii wrote:
         | Mitochondrial health is considered a strong proxy for overall
         | health.
        
       | rustcleaner wrote:
       | I expect such lively news to make this comment section the
       | powerhouse of the front page. :^)
        
         | cmiller1 wrote:
         | It's funny that this phrase has had such staying strength,
         | while the key word in it, "powerhouse," has fallen out of
         | fashion. The more modern American English way to phrase it
         | would be "the power plant of the cell."
        
           | jagged-chisel wrote:
           | Can you describe the distinction?
        
             | AdmiralAsshat wrote:
             | Distinction: I am a millennial, and actually had to go look
             | up just now what a "powerhouse" is. I am familiar with the
             | term in its metaphorical sense, but was heretofore
             | unacquainted with the literal definition. "Power plant" or
             | "power station" would, yes, be more immediately understood
             | by my generation. The phrase "Mitochondria is the
             | powerhouse of the cell" would read to modern children like
             | saying "The mitochondrion is the rock star of the cell."
             | 
             | These things do happen. I was in my 30s before I learned
             | what the "firewall" of a car was...
        
           | mkaic wrote:
           | Anecdotally, I feel like I've heard "powerhouse" used
           | somewhat regularly when describing impressive people, i.e.:
           | "Such-and-such is an absolute _powerhouse_ on the field ", or
           | "That person is so productive, they're a _powerhouse_ ".
           | 
           | So maybe the original usage has been subsumed by "power
           | plant", but I think the word has alternative meanings which
           | persist.
        
           | selimthegrim wrote:
           | I'm pretty sure people still talk about powerhouses of
           | hydroelectric dams
        
           | dendrite9 wrote:
           | That's an interesting thought, I haven't picked up on it but
           | you're right. Most of my associations with powerhouse are
           | from trails or ares that used to have powerhouses and now
           | have empty buildings, ruins or traces left over. I do think
           | about powerhouses in the context of dams but that is likely
           | leftover from an earlier time.
        
           | hildolfr wrote:
           | It kind of just shifted distinctions.
           | 
           | Powerhouse is a common way to describe an athlete, a high
           | performance engine, or a very strong stock buy -- it has just
           | moved away from the infrastructural uses.
        
       | wwwtyro wrote:
       | I'm sure there's a fantastic midi-chlorian joke here.
        
       | GaryNumanVevo wrote:
       | the mitochondria are alive, and they're doing just fine
        
       | netcraft wrote:
       | this is the first ive heard of mitochondria replicating
       | separately and distinctly from the host cell, how fascinating!
       | 
       | Are we saying that mitochondria have their own life cycle inside
       | of a cell? living/dying/replicating in the span of the "life" of
       | a single host cell? When a host cell reproduces, how does the
       | mitochondria get produced in the new cell to get things started?
       | 
       | Cant wait to research this later.
        
         | marcosdumay wrote:
         | > When a host cell reproduces, how does the mitochondria get
         | produced in the new cell to get things started?
         | 
         | Each half of the cell keeps the mitocondria that were living
         | inside it.
        
         | andrewla wrote:
         | The two halves of the divided cells will usually both have
         | mitochondria. Not always, though; sometimes cell division
         | leaves one cell without any mitochrondria. That usually results
         | in a non-viable cell, but sometimes the cell can survive with
         | limited capacity. Some species that used to have mitochondria
         | have apparently been through this process and have evolved to
         | survive in their absence; Giardia duodenalis for example.
        
           | jamiek88 wrote:
           | Oh wow! It never occurred to me that there are creatures
           | without mitochondria.
        
             | dekhn wrote:
             | https://www.science.org/content/article/first-eukaryotes-
             | fou...
        
       | adastra22 wrote:
       | I don't understand the headline (yes I skimmed the article). Why
       | would mitochondria not be alive? What does that even mean?
        
         | ssalka wrote:
         | I imagine it's similar to how viruses are not considered to be
         | alive, since they cannot reproduce without a host cell?
         | 
         | But I have never been a fan of that argument either, both seem
         | alive to me.
        
           | georgeecollins wrote:
           | I think the idea here is that mitochondria developed
           | independent of cells and later lived exclusively inside of
           | them. In other words, they reproduced without cells. I am not
           | sure, please correct me if I am wrong.
        
             | semperdark wrote:
             | You're not wrong. But over the enormous amount of time
             | since, the "duplicate" organelles and systems needed for
             | independent living were steadily carved out of
             | mitochondria. While they do have their own DNA and
             | replication process, the DNA is basically limited to
             | specific things they need to perform their energy-
             | generation functions and the replication happens when
             | triggered by host cell replication.
             | 
             | It's a bit like if you took the heart from an animal and
             | transplanted it into a human: is it meaningful to call it
             | independently alive? Maybe, it depends what question you're
             | trying to ask.
        
             | dekhn wrote:
             | No, the predecessors of mitochondria were also cells and
             | they reproduced through cellular division.
        
           | adastra22 wrote:
           | I don't know of any definition of "alive" that can survive
           | application of a reductive understanding of biology that
           | doesn't either count viruses as being "alive," or decide that
           | nothing is alive.
           | 
           | The uncertainty, I understood, was whether to classify them
           | as distinct organisms the way we classify other species, as
           | they are intrinsically parasitic for their replicative
           | capability.
        
         | georgeecollins wrote:
         | I am terrible at biology but I will try. The idea is that
         | mitochondria is not a component of a living organism, but an
         | organism that once lived independently of the cell.
        
         | UncleOxidant wrote:
         | "If we think of mitochondria as non-living organelles..."
         | 
         | mitochondria were thought to just be a component of the cell.
         | But they have their own DNA separate from that in the cell's
         | nucleus. They replicate on their own like bacteria.
        
           | marcosdumay wrote:
           | > mitochondria were thought to just be a component of the
           | cell.
           | 
           | ... hundreds of years ago, for a short time after they were
           | discovered.
           | 
           | We know that they behave like bacteria for almost as long as
           | we know that they exist.
        
             | outworlder wrote:
             | They "behave as" bacteria. _Are_ they bacteria? Are they
             | 'alive' by themselves? That's the distinction.
        
               | marcosdumay wrote:
               | > Are they 'alive' by themselves?
               | 
               | That's a discussion about word semantics that has no
               | relation to biology. Biologists have been occupied with
               | it for centuries, just like computer people have lost
               | time on "what's intelligence?", but neither one is
               | relevant for either field.
               | 
               | > Are they bacteria?
               | 
               | Once upon a time, their ancestors were. I do not know
               | exactly where biologists trace the line, but this is also
               | about word semantics. It's just a case of it that helps
               | people communicate better, so there is a line, I just
               | don't know what it is.
        
               | adastra22 wrote:
               | What do you mean by "alive?" Because of course they are
               | alive, regardless of whether you consider them bacteria
               | or not. There is a strange definition of "alive" that is
               | being used by you and the author article that I'm not
               | understanding.
               | 
               | If a mitochondria is not "alive," then is it dead? Even
               | if it is taking part in an active, living cell?
        
           | adastra22 wrote:
           | Organelles are alive too. All active biological systems are
           | alive.
           | 
           | Mitochondria have for many generations now been known to have
           | their own DNA and replicate on their own. So I'm not sure
           | what new distinction is being drawn?
        
             | twothreeone wrote:
             | I _think_ what they mean is it's not typically listed as a
             | "life form" in its own right, i.e., there's no Domain under
             | which one would classify Mitochondria - maybe just calling
             | them bacteria would capture the article's intent?
             | 
             | So, the modification would be that we are living in
             | symbiosis with mitochondrial bacteria, similar to how we
             | live in symbiosis with our gut bacteria, rather than them
             | being classified as "organelles" of eukaryote cells.
        
               | pleurotus wrote:
               | That's more a flaw of classification systems though.
               | Because even if they comprise a distinct life form does
               | not mean they need to have a unique species. Consider
               | lichen, which comprise two (or more!) separate "species"
               | which becomes a meaningless distinction when they cannot
               | survive on their own, or even if they could, not in a
               | form recognizable in any wayas they were when they were a
               | part of the symbiotic system
        
               | hughesjj wrote:
               | I mean at that point what do we consider multicellular
               | organisms? Did you see what was going on with those frog
               | skin cells and "xenobots"? Also, our gut bacteria kinda
               | makes us a symbiote at a larger scale.
        
               | pishpash wrote:
               | Of course it is classified. In Wikipedia itself there is
               | a phylogenetic tree listing its closest relative the
               | alphaproteobacteria: https://en.wikipedia.org/wiki/Mitoch
               | ondrion#Origin_and_evolu...
        
               | adastra22 wrote:
               | As others note, it is classified in the tree of life. We
               | know approximately what kind of bacteria it evolved from,
               | and mitochondria themselves constitute their own
               | divergent branch of the tree of life (there are many
               | longitudinal studies of mitochondria across species).
               | 
               | But if you wanted classify them based on functionality
               | rather than evolutionary history, I'd say they're more
               | like viruses. They have only a handful of genes
               | themselves, and exploits the nucleus' genetic material
               | for all the other proteins it needs to function.
        
             | dekhn wrote:
             | Depends on your definition of organelle (whether you limit
             | it to plastids/mitochondria, both of which were derived
             | from external independent living cells, or use a more
             | expansive definition that includes more cell compartments
             | that weren't derived from independent living cells).
             | 
             | General acceptance of the endosymbiont theory is a
             | relatively recent (much less than 50 years) phenomenon.
        
               | adastra22 wrote:
               | "General acceptance" is a subjective criteria. But the
               | endosymbiont theory is >60 years old at this point.
        
           | agumonkey wrote:
           | I was looking for specific notions explaining the emergence
           | of this kind of endosymbiosis, anybody has links ?
        
       | debacle wrote:
       | > If one considers bacteria as living entities -- and all
       | biologists seem to -- then it is impossible to explain why
       | mitochondria are not.
       | 
       | There seems to be a strange, half-hubris, half-pride vein that
       | runs through Humanity that would see us as lesser for being hosts
       | to benevolent bacteria, despite us very obviously being unable to
       | survive without benevolent bacteria.
        
         | jcims wrote:
         | I think it just attacks the wholeness of 'self' and starts to
         | reveal the true complexity of nature.
        
           | echelon wrote:
           | We didn't evolve to understand "self", and indeed most
           | animals do not. There was no evolutionary pressure to do so.
           | We're having to discover it piece by piece.
        
             | r14c wrote:
             | We aren't driven solely by evolutionary pressure. We can
             | (and have) developed cultures that can easily accept that
             | humans are "just" part of a larger system, even having a
             | unique role, without having to be superior. Our culture
             | isn't like that, of course. We are obviously doing a good
             | job of being "in charge" of the planet and definitely not
             | charging headfirst into a mass extinction event with our
             | collective eyes closed.
        
             | shawnz wrote:
             | We had evolutionary pressure to evolve self-preservation,
             | and that stars with self, doesn't it?
        
         | robertlagrant wrote:
         | Everyone knows we're already that. The importance of gut
         | microbiome for one - cited loads.
        
         | dist-epoch wrote:
         | Unable to survive without them is pushing it. When one takes
         | strong antibiotics most of them die.
        
       | readthenotes1 wrote:
       | "In the early 19th century, "
       | 
       | With that level of proofreading, I'm not sure what else was wrong
       | in the article...
        
       | csours wrote:
       | For a fictional macro version of the Margulis hypothesis, I'd
       | recommend 'Alien Clay' by Adrian Tchaikovsky
        
       | euparkeria wrote:
       | It reminds me the game Parasite Eve.
        
       | escapecharacter wrote:
       | If we label mitochondria as alive, that would mean prison
       | laborers must count as living, too.
        
         | MrMcCall wrote:
         | Sir/Ma'am, I live in America. What is reasonable and
         | compassionate and sensible is simply beyond the grasp of most
         | everyone, looks to me.
        
         | otabdeveloper4 wrote:
         | > thinly veiled abortion argument
         | 
         | Kek.
        
       | kylehotchkiss wrote:
       | Interesting argument
       | 
       | > control bioenergetics across the eukaryotic tree of life.
       | 
       | What types of outcomes do we unlock when we can control
       | bioenergetics?
        
         | dekhn wrote:
         | unlimited power
        
       | pieter_mj wrote:
       | I'll add the following to the conversation :
       | 
       | https://x.com/niko_kukushkin/status/1854593093636350387 and
       | https://web.archive.org/web/20170506064530/https://inference...
        
       | j_bum wrote:
       | Any time I read a mitochondria post like this, I strongly
       | recommend that others who find the topic interesting check out
       | _Power, Sex, and Suicide_ by Nick Lane.
       | 
       | Excellent book!
        
         | meowkit wrote:
         | +1 to Nick Lane
         | 
         | I've only read The Vital Question, but I felt it was a great
         | introduction to biochem for someone not in the field.
        
           | pkghost wrote:
           | Absolutely loved TVQ. The insight about mitochondrial DNA
           | inheritance being exclusively from the mother, thus
           | motivating female fingerprinting of male nucleic DNA for
           | gamete viability (via courtship rituals, pheromones, plumage,
           | etc)...
        
         | rsync wrote:
         | Came here to recommend Power, Sex, and Suicide. It is a
         | fascinating book.
        
         | grantmuller wrote:
         | The Vital Question covers this topic and is in general a really
         | great basic education in biological energy production.
        
       | TeeMassive wrote:
       | > Mitochondrial DNA mutates 100-1,000 times faster than the human
       | genome
       | 
       | This statement is very interesting for two reasons:
       | 
       | 1) We not consider mitochondrial DNA as part of the human genome
       | when it's clearly is and can be used to establish the maternal
       | genetic lineage.
       | 
       | 2) Traditionally, we always think of telomere reduction and
       | genetic mutations as the root cause of aging but not
       | mitochondrial genetic damages.
        
         | rbanffy wrote:
         | > 2) Traditionally, we always think of telomere reduction and
         | genetic mutations as the root cause of aging but not
         | mitochondrial genetic damages.
         | 
         | A lot of research is looking into the role of mitochondrial
         | damage as causes for a number of conditions.
        
       | swasheck wrote:
       | a lot of focus on the definition of "alive" in the comments, but
       | i think that the weight of this rests on it being a step toward
       | confirming the endosymbiotic relationship theory which states
       | that mitochondria were potentially part of another eukaryotic
       | cells carrying what would become mitogchodria were engulfed by
       | another cell. this affected cellular development by outsourcing
       | energy production for the cell itself. a lot of times the results
       | seem "self-evident" but you still have to find evidence to
       | support or reject a theory and this seems like a step in that
       | direction.
        
         | ramon156 wrote:
         | I still think about the fact that we're this close to proving
         | the protocell theory, proving that we can create life from no
         | life. Last time I read about it was 2021, and I'm really
         | curious when the day arises we succeed
        
       | renewiltord wrote:
       | They are obviously alive, but also we are obviously a colony
       | organism. The various bacteria we transmit from mother to child,
       | the mitochondria inherent to our cells, all of this stuff is just
       | part of a self-similarity of life from top to bottom. With
       | sufficient zoom-out, we need not treat individuals (or pairs) as
       | the only unit of life replication.
        
       | andrewla wrote:
       | I read the article waiting for an answer to the question "in what
       | operational sense does this matter?" but it never arrived.
       | 
       | The question posed is whether we consider mitochondria to be
       | "alive". It's just a word, who cares. What do we do differently
       | given this assumption?
        
         | bmacho wrote:
         | Ew. That's always an uncomfortable read.
        
         | pizzathyme wrote:
         | Exactly. Seems similar to "are LLMs alive"? What practical
         | purpose would an answer to that question serve?
        
           | The_Colonel wrote:
           | That seems to be an overly reductive view on the value of
           | knowledge.
           | 
           | What practical purpose does studying ancient civilizations
           | have? Why do we send expensive telescopes into space to study
           | faraway galaxies and try to uncover mysteries of the big
           | bang? When can we expect the results from number theory to
           | lower the price of gas at the pump?
        
             | andrewla wrote:
             | But the definition of a word is not knowledge.
             | 
             | Knowing that mitochondria have their own DNA is knowledge.
             | Knowing that they reproduce independently of their home
             | cell is knowledge. Learning whether they evolved from a
             | separate viable organism would be knowledge. Learning
             | whether we can make them viable, or breed them separately,
             | and use them in therapies -- all knowledge.
             | 
             | Whether they are "alive" or not is just the definition of a
             | word.
        
               | dekhn wrote:
               | Much of science is about defining words in ways that
               | match the underlying general structure of the system
               | being studied.
               | 
               | A subset of scientists want to come up with an
               | operational definition of "What is life", which may or
               | may not include things like viruses and mitochondria. As
               | you say, it's mostly definitional, but by defining this,
               | we can potentially make our understanding match up with
               | the latent reality.
        
         | nemonemo wrote:
         | It doesn't seem the article addresses this, but I'd ask these
         | questions: "would it be possible that mitochondria's
         | evolutional interest and the organism's interest are not
         | aligned?" "how many independent DNA can an organism possess?"
         | "why mitochondria do not elicit immune reactions? Or can they?"
        
           | hammock wrote:
           | 1) https://en.wikipedia.org/wiki/Mother%27s_curse
           | 
           | 2) By "organism" I assume you mean "cell" since humans have
           | several thousand different species with their own DNA living
           | on or inside the body at any given moment. We can speak of
           | animal cells, which have two (species and mitochondria) - and
           | plant cells, which have three (species, mitochondria, and
           | chloroplasts). If there can be one two or three, I don't see
           | why there couldn't be even more.
           | 
           | 3) Mitochondria are usually sequestered within the cell,
           | which limits their exposure to immune cells. The immune
           | system primarily targets pathogens that are outside the host
           | cells. In fact, some pathogens can exploit mitochondrial
           | pathways to evade immune detection - the most famous of which
           | is HIV.
        
         | davideg wrote:
         | > _Defining mitochondria as "nonliving" isn't just a
         | classification mistake, nor a question of word choice. Rather,
         | it is a fundamental misunderstanding of the nature and role of
         | mitochondria. It inherently undermines our understanding of
         | biological systems and deeply influences the tools we build to
         | study them._
         | 
         | Once you accept mitochondria as alive, you might be motivated
         | to explore its "potential" niche, as described by the author.
         | The example of implanting cross-species mitochondria in human
         | cells (e.g. from a gorilla) might lead to novel therapies.
         | 
         | It's about breaking outside the box of mitochondria having to
         | live inside specific environments.
        
           | andrewla wrote:
           | So the theory is that if we don't accept them as alive, then
           | we can't experiment with implanting cross-species
           | mitochondria in human cells? Why not? What stops us from
           | doing this?
        
             | davideg wrote:
             | This is a fair point. I can see the excitement around
             | recognizing that mitochondria is alive to motivate
             | exploring its other functions. But I think you're right
             | someone might be interested in that exploration regardless
             | of whether it's considered alive.
             | 
             | Edit: to your point, there are plenty of scientists
             | interested in studying viruses and much debate about
             | whether or not they are alive. Ultimately it probably
             | doesn't matter.
             | 
             | I do think when you consider mitochondria to be alive, it
             | broadens the scope of your thinking because you start
             | considering each characteristic of life in relation to
             | mitochondria. You might not be motivated to do that without
             | thinking in those terms.
        
           | davideg wrote:
           | I recognize that you might be motivated to explore removing
           | and implanting mitochondria regardless of whether you
           | consider it to be alive (as you might think about implanting
           | an organ from another source).
           | 
           | I think the main point the author is making is to not fall
           | prey to reductive thinking about mitochondria's potential and
           | less about the question of "aliveness". We were all taught
           | about mitochondria producing ATP, but it sounds like it
           | serves many other functions and there's a lot more to explore
           | about its potential in synthetic biology and therapeutics.
        
         | dekhn wrote:
         | It matters for a number of reasons, but the main reason in
         | terms of pure biology is that it was not originally recognized
         | that cells could absorb other cells and utilize them for the
         | absorbed cell's natural function.
         | 
         | This meant, importantly, that we learned cells did not always
         | need to evolve a functionality from scratch, but could acquire
         | it through phagocytosis.
         | 
         | It's also a useful tool for studying evolution for many
         | reasons.
        
           | andrewla wrote:
           | Whether or not mitochondria were once viable independent
           | organisms that were absorbed by early eukaryotes does not
           | depend on whether we call their modern descendants "living"
           | or not. If we determine that they did, then we still don't
           | have to call them alive -- certainly things like mitosomes
           | exist and are suspected to have either evolved from
           | mitochondria or evolved after amitochondrial division, but do
           | not have DNA and do not reproduce independently but fulfil
           | similar functions.
           | 
           | We know they have DNA, we know they reproduce independently
           | of the host cell, we know to a degree why they tend to move
           | to both sides on cell division. We know lots of stuff about
           | them and we can always learn lots more. Whether they are
           | "alive" or not has absolutely no bearing on that, other than
           | to naval-gaze.
        
             | dekhn wrote:
             | Oh, I see, you're getting hung up on the use of the term
             | alive for modern mitochondria.
             | 
             | This sort of definitional argument is not interesting to
             | me.
        
               | andrewla wrote:
               | I think we're in agreement then -- this article is not
               | about "did mitochondria evolve from absorbed viable
               | organisms as opposed to evolving directly", which is an
               | interesting question that impacts our understanding of
               | evolution in microbiology. The article is about whether
               | "Microchondria Are Alive" which is a useless naval-gaze.
        
               | dekhn wrote:
               | I dunno if I agree it's a total navel gaze.
               | 
               | For example I could easily see a scientist asking the
               | question, "if mitochrondira are not alive, at which point
               | did the phagocytosis of the initial prokaryotic cell lead
               | to the mitochondria not being alive?" "What components
               | were lost in the cell that lead to the loss of life?" I
               | agree these aren't particularly useful, and are
               | ultimately definitional, but definitions matter a lot in
               | science, especially when paradigms change.
        
               | andrewla wrote:
               | This is a much more interesting question, and this is
               | what I mean by an operational definition of life. In your
               | first question, "alive" can have useful operational
               | definitions -- whether it is viable outside of a cell,
               | whether it has or had its own immune system and
               | structure, how it survived without the organelles that
               | other full-fledged cells seem to have but mitochondria
               | lack, etc.
               | 
               | The question in the abstract is not really useful except
               | to answer trick questions in bar trivia.
        
         | ASalazarMX wrote:
         | I was equally dismissive of the actual importance of
         | philosophizing whether mitochondrias are alive or not, but this
         | paragraph made me change my mind.
         | 
         | > It seems Mitochondria are not bound to their host cell; they
         | can travel between different cells. Although different species
         | carry distinct mitochondria, experiments show that mitochondria
         | from one species can be transferred to another.
         | 
         | > In 1997, scientists isolated mitochondria from chimpanzees
         | and gorillas and showed that they are naturally internalized
         | and integrated into human cells. Notably, the addition of
         | external mitochondria even showed therapeutic benefits in heart
         | failure and spinal cord injury. Thus, the potential niche that
         | mitochondria can live in is greater than their effective niche.
         | 
         | So it seems like they are more symbiote than organelle, that's
         | amazing.
        
       | MostlyStable wrote:
       | >Defining mitochondria as "nonliving" isn't just a classification
       | mistake, nor a question of word choice. Rather, it is a
       | fundamental misunderstanding of the nature and role of
       | mitochondria. It inherently undermines our understanding of
       | biological systems and deeply influences the tools we build to
       | study them.
       | 
       | This assertion is made but not supported. I don't think I
       | understand the importance of this distinction, assuming that
       | everyone already agrees about the evolutionary and mechanical
       | facts about mitochondria, but as far as I can tell, no one
       | disagrees that mitochondria were originally free living cells, or
       | that they have their own DNA, or any of the other relevant facts
       | about their origins or how they work in the cell. It's merely an
       | argument about what it means to be alive. Which is
       | philosophically interesting, but practically unimportant for the
       | practice of biology.
       | 
       | This seems like a purely semantic debate with no broader
       | importance.
        
         | wrycoder wrote:
         | From an article cited in the OP [0],
         | 
         |  _More than 95% of all proteins located in the mitochondrial
         | compartments are encoded by the nuclear DNA, synthesized in
         | cytoplasmic ribosomes and imported into mitochondria. These
         | include factors that regulate mitochondrial DNA (mtDNA) gene
         | expression such as mtDNA and RNA polymerases, mitochondrial
         | transcription factors, RNA processing and modifying enzymes,
         | transcription termination factors, mitochondrial ribosomal
         | proteins, aminoacyl-tRNA synthetases, and translation factors
         | (1, 2)._
         | 
         | It's clear that a mitrochondrial element can't live for long
         | without the presence of the host cells, so, like a virus, it
         | doesn't meet all the requirements to be considered fully
         | living.
         | 
         | [0] https://pmc.ncbi.nlm.nih.gov/articles/PMC23071/
        
       | m3kw9 wrote:
       | So what now? We give them rights?
        
         | itsafarqueue wrote:
         | Or deport them.
        
       | IAmNotACellist wrote:
       | The fact that every child on the planet is religiously taught
       | that the mitochondria is the powerhouse of the cell is all the
       | evidence I need that we're upholding a primordial contractual
       | agreement and these are the conditions to which we are beholden.
       | 
       | Name a single biological entity that has a better PR department.
       | The only one that comes close is Athlete's Foot, which makes the
       | victim sound cool.
        
         | com2kid wrote:
         | I actually never heard the phrase until I got online and saw
         | the meme!
         | 
         | My biology classes did have us gene editing bacteria to chance
         | its color. That was fun!
         | 
         | > The only one that comes close is Athlete's Foot, which makes
         | the victim sound cool.
         | 
         | The best cure for athletes foot is a 30 minute soak in diluted
         | bleach. Get a wash basin, fill it with warm water, and add
         | enough bleach so that it tingles a little bit.
         | 
         | Do this every other day 3 times, e.g. Monday, Wednesday,
         | Friday. Problem solved.
         | 
         | Make sure to clean out the shoes as well, ideally not wearing
         | any infected shoes for a few days at least, and soak the
         | insides with Lysol a few times to prevent reinfection.
        
           | protonbob wrote:
           | According to my doctor, this can weaken the skin too much. 30
           | minutes is quite a long time.
        
           | beng-nl wrote:
           | I have the same experience - never heard of it until I saw
           | the meme. I have a feeling it's something local to American
           | schoolchildren.
        
           | piuantiderp wrote:
           | Do the same but with Potassium chloride or bicarbonate. Done!
           | And way safer
        
         | jamiek88 wrote:
         | Excellent point.
         | 
         | Are there mitochondria in neurons?
        
           | JumpCrisscross wrote:
           | > _Are there mitochondria in neurons?_
           | 
           | Yes [1].
           | 
           | [1] https://pmc.ncbi.nlm.nih.gov/articles/PMC7373250/
        
           | outworlder wrote:
           | Yes. Neurons are very energy hungry.
        
           | piombisallow wrote:
           | Every cell in the body (except blood cells) has mithocondria.
        
             | devilbunny wrote:
             | Nitpick: except _red_ blood cells. White cells very much do
             | have mitochondria.
             | 
             | RBC's don't need them because they are incredibly low-
             | metabolism. It's energetically cheaper for the organism
             | just to make them, let them go for a few months, and then
             | recycle the components.
        
         | arcticbull wrote:
         | Unfortunately Jock Itch (the same type of fungus) didn't get
         | the same PR treatment.
        
         | Izikiel43 wrote:
         | Achilles tendon?
        
         | hinkley wrote:
         | The Sun.
         | 
         | As far as I'm aware we've never worshipped mitochondria. And
         | unless you want to count eating which is technically true but
         | not philosophically so, we don't sacrifice plants or animals to
         | mitochondria.
        
           | tim333 wrote:
           | Not very biological though.
        
         | YetAnotherNick wrote:
         | I don't know why but for some reason, the name Mitochondria is
         | very easy to remember even though it sounds complex.
        
         | ampdepolymerase wrote:
         | > _the mitochondria is the powerhouse of the cell_
         | 
         | The explanation doesn't get much better at higher levels. You
         | have the Krebs cycle which biology people religiously memorize
         | but it doesn't really explain much either. The actual
         | interesting part is usually handwaved away as "magical
         | enzyme/protein" catalysis. Understanding how the mitochondrial
         | proteins/enzyme catalysts function would usually require a
         | graduate degree, and maybe a background in biochemistry and
         | biophysics.
        
           | im3w1l wrote:
           | If you haven't, I suggest you look up an on how ATP Synthase
           | uses the proton gradient to create ATP. It's quite amazing.
           | It's literally a little nano-machine.
        
         | tim333 wrote:
         | The brain gets good PR. The brain dead are thought unfortunate.
        
         | HaZeust wrote:
         | >"Name a single biological entity that has a better PR
         | department. The only one that comes close is Athlete's Foot,
         | which makes the victim sound cool."
         | 
         | Love this line! Phoenix Worm came to mind.
        
       | JumpCrisscross wrote:
       | Mitochondria are why I'm a Rare Earther.
       | 
       | In Earth's history, mitochondrial endosymbiosis occurred once.
       | Without that you don't have the energy budget for complex life.
       | Moreover, there may be a narrow window where it _can_ happen:
       | modern microbiology has defences and selection pressures that it
       | make inhospitable to the hobbling chimerae the first
       | mitochondrial cells would have been.
       | 
       | Until mitochondria, the emergence of life from nothing is
       | plausible. With mitochondria, its progression to complex,
       | multicellular and intelligent life makes sense. Both processes in
       | small steps can be replicated, more or less, in the lab. But that
       | one moment is not and has not been. As a result, I think the
       | universe has lots of living slop but very few plants and animals.
       | 
       | (Aside, look at ATP go:
       | https://www.youtube.com/watch?v=lUrEewYLIQg&t=939s)
        
         | outworlder wrote:
         | Mitochondria seems to have been an 'accident', yes.
         | 
         | That does not mean that other lifeforms in different planets
         | require mitochondria or equivalent organelles. As long as they
         | can perform the necessary chemical reactions (which could be
         | different in a different environments) and extract enough
         | energy, they should be good.
         | 
         | How did mitochondria evolve in the first place? Could they have
         | remained as independent organisms and use their massive energy
         | budget to evolve independently?
        
           | JumpCrisscross wrote:
           | > _long as they can perform the necessary chemical reactions_
           | 
           | That mitochondria are conserved as an independent organelle
           | across almost [1] all eukaryotes, across billions of years of
           | history, suggests this is something the nuclear can't easily
           | in house.
           | 
           | [1] https://pmc.ncbi.nlm.nih.gov/articles/PMC6343361/
        
             | outworlder wrote:
             | Maybe!
             | 
             | That could also suggest that any other strategies were just
             | out competed by this one and lost the opportunity to
             | develop further.
        
               | JumpCrisscross wrote:
               | > _other strategies were just out competed by this one
               | and lost the opportunity to develop further_
               | 
               | Absolutely. It also means--however--that any niche where
               | alternative _did_ exist, when exposed to mitochondrial
               | life, they lost.
               | 
               | Now that I think about it, it would be pretty funny if
               | we're this universe's cheela [1], a freakishly
               | overclocked biosphere that runs faster not because it had
               | to but because it happened to.
               | 
               | [1] https://en.wikipedia.org/wiki/Dragon%27s_Egg
        
               | ajuc wrote:
               | Evolution is path-dependent. Notice that mammals were
               | comprehensively outcompeted by dinosaurs till asteroid
               | removed them and gave mammals time and niches to develop
               | in. If you recreated dinosaurs right now they would lose
               | to mammals (for example to homo sapiens).
               | 
               | It's perfectly possible that mitochondria are the
               | dinosaurs of "cell powerplants" that just haven't
               | encountered the asteroid to let other (ultimately better)
               | solutions develop.
        
             | jamiek88 wrote:
             | There are organisms without mitochondria too though. So
             | it's viable.
        
               | JumpCrisscross wrote:
               | > _are organisms without mitochondria too though. So it's
               | viable._
               | 
               | True, it's an anaerobic ersatz cnidarian [1] that may be
               | an escaped cancer [2].
               | 
               | [1] https://daily.jstor.org/who-needs-mitochondria-
               | anyway/
               | 
               | [2] https://pmc.ncbi.nlm.nih.gov/articles/PMC6343361/
        
               | Rumudiez wrote:
               | > [discovered in] gut bacteria from a researcher's pet
               | chinchilla
               | 
               | wow. we could be surrounded by so many extraordinary
               | organisms and not even know it because there's so much
               | variety just in our own backyards
        
               | satvikpendem wrote:
               | There was a study where participants were asked to swab
               | their belly buttons and lots of new organisms were found.
               | 
               | https://www.theatlantic.com/health/archive/2012/12/1-458-
               | bac...
        
               | im3w1l wrote:
               | Absolutely fascinating. Especially the exotic
               | multicellularity part. Maybe if it evolves even more
               | multicellularity it will struggle with cancers of its own
               | and have to reevolve tumor suppression, wouldn't that be
               | something?!
        
             | xeeeeeeeeeeenu wrote:
             | https://en.wikipedia.org/wiki/Monocercomonoides
             | 
             | >It is the first eukaryotic genus to be found to completely
             | lack mitochondria, and all hallmark proteins responsible
             | for mitochondrial function. The genus also lacks any other
             | mitochondria related organelles (MROs) such as
             | hydrogenosomes or mitosomes. Data suggests that the absence
             | of mitochondria is not an ancestral feature, but rather due
             | to secondary loss.
        
           | eboynyc32 wrote:
           | It's so pathetic to keep hearing that dna is an accident ,
           | life is an accident, mitochondria is an accident. What is an
           | accident that natures says "oooops". When will we take our
           | heads out of the sand and realize the universe is alive and
           | creating everything. There are no goddamn accidents !!!!
        
             | exe34 wrote:
             | all happy little accidents!
        
             | AlphaEsponjosus wrote:
             | What? When saying that "X" is an accident, nobody means
             | "nature says 'oooops'. Nature is neither conscious nor
             | alive, if universe were alive and creates and shapes life,
             | why is there so many errors happening in the universe?
             | 
             | Everything exist by " accident", and that means that is the
             | result of random events that happen unexpectedly in
             | unimaginable places, leading to an environent were the
             | outcome of this events causes more random events.
             | 
             | Why universe insist in making life so uncommon if it has
             | the secret to create and replicate?
        
           | pieter_mj wrote:
           | Mitochondria are bacteria that were endosymbioticized into
           | what became the eukaryotic cell. Mitochondria can still
           | survive (live) independently and functionally in the blood
           | when they're separated from platelets and microvesicles.
           | Mitochondria are the software that epigenetically switch
           | nuclear DNA genes on and off. That sofware can be tweaked by
           | light, for instance UV light or IR light. mtDNA mutates
           | x1000000 more rapidly than nuclear DNA.
        
             | dekhn wrote:
             | uhh where did you get " Mitochondria are the software that
             | epigenetically switch nuclear DNA genes on and off."
        
           | liyamchitayat wrote:
           | One interesting thing is that many reactions actually have to
           | occur in their own compartment- and since we have not lost
           | the mtDNA, it may suggest that having an additional control
           | center is beneficial.there are some interesting theories
           | about the relations of that to lifespan
           | https://www.cuimc.columbia.edu/news/mitochondria-are-
           | flingin....
        
             | im3w1l wrote:
             | Couldn't it be that we haven't fully lost mtDNA because
             | it's simply a very slow process that has not yet run its
             | course?
        
               | aydyn wrote:
               | Given how old mitochondria are it seems more likely that
               | its more efficient to have its own DNA.
               | 
               | DNA isn't just abstract information, it's also where the
               | first step of protein / enzyme construction occurs. DNA
               | location matters.
        
           | patcon wrote:
           | Mitochondria allowed who different energetic regimes and
           | structures. Like the scaffold that allows multicellular
           | organisms to even hold together simpler are not possible
           | (energetically) without mitochondria. It took the whole
           | marriage of the two systems to allow the energy state (the
           | "chemical reactions" as you say) to be possible
           | 
           | SFI Complexity podcast has a few great episodes on this
        
           | WalterSear wrote:
           | > Could they have remained as independent organisms and use
           | their massive energy budget to evolve independently?
           | 
           | This presumes that their energy budget was massive to begin
           | with, rather than being selected for over time.
        
         | maxerickson wrote:
         | So only a few billion planets with complex life?
        
           | JumpCrisscross wrote:
           | > _only a few billion planets with complex life?_
           | 
           | Or trillions or tens or ones. Depends on what number you put
           | in the exponent. Currently, we don't have useful constraints
           | on that figure.
           | 
           | (A lot of popular astrobiology pulls the "if we could only
           | get 1% of the market we'd be billionaires" schtick.)
        
             | dylan604 wrote:
             | The astrobiology schtick is just a what if thought
             | experiment though, and nothing proven nor claimed to be
             | fact. It's just a way to show that the scale of the
             | universe is "hugely, mind-bogglingly big" while trying to
             | pull a number that our squishy lobes could comprehend. If
             | 1% of mind-bogglingly huge number, then 1% of that, then 1%
             | of that yields a still mind-bogglingly big number. The laws
             | of large numbers would suggest something as well.
             | Otherwise, "its an awful waste of space"
        
               | JumpCrisscross wrote:
               | Sure. The point is 1% is a _huge_ fraction for a lot of
               | things. Market share. And many reaction cross sections.
        
         | WWWWH wrote:
         | I have a chloroplast for you on line two; can you hold?
        
           | JumpCrisscross wrote:
           | They're sensitive about the Oxygen Holocaust [1][2]?
           | 
           | [1] https://en.wikipedia.org/wiki/Great_Oxidation_Event
           | 
           | [2] https://en.wikipedia.org/wiki/Purple_Earth_hypothesis
        
         | casenmgreen wrote:
         | I may be wrong, but I recall reading recently it had been found
         | the same event had occurred again, fairly recently (hundreds of
         | thousands of years, could be millions) in some species of
         | bacteria or something like that.
         | 
         | Here's a thought, also; maybe once this has happened, it tends
         | to crowd out needing to happen again.
        
           | JumpCrisscross wrote:
           | > _it had been found the same event had occurred again,
           | fairly recently_
           | 
           | Would love to know the source if you have it.
        
             | joshuahedlund wrote:
             | Might be referring to this:
             | https://newatlas.com/biology/life-merger-evolution-
             | symbiosis...
        
               | casenmgreen wrote:
               | Yes. That's the one. Thank you.
        
               | casenmgreen wrote:
               | Huh. This is the correct news, but a different article to
               | the one I recall. However, very interesting;
               | 
               | > The first occurred about 2.2 billion years ago, when an
               | archaea swallowed a bacterium that became the
               | mitochondria.
               | 
               | > The second time happened about 1.6 billion years ago,
               | when some of these more advanced cells absorbed
               | cyanobacteria that could harvest energy from sunlight.
               | 
               | > And now, scientists have discovered that it's happening
               | again. A species of algae called Braarudosphaera
               | bigelowii was found to have engulfed a cyanobacterium
               | that lets them do something that algae, and plants in
               | general, can't normally do - "fixing" nitrogen straight
               | from the air, and combining it with other elements to
               | create more useful compounds.
               | 
               | So, tremendously rare, at least to our knowledge at this
               | time, but not a one-off.
        
         | hurpdurpdurp wrote:
         | I know nothing about biology, pardon my ignorance. From the
         | article it sounds like mitochondria were a separate organism
         | that has perhaps simplified through specialization and is
         | currently on the boundary of being an independent life form. It
         | also sounds like there are other structures (golgi apparatus
         | are mentioned?) which are not on the bubble. Are we sure that
         | there is not an arrow of time here, where once those other
         | structures were also semi-independent and have become less so?
         | 
         | More broadly, it leads me to wonder whether cellular life might
         | eventually/might have at some point specialize towards hosting
         | novel endosymbioses.
         | 
         | Either scenario, assuming what I'm saying isn't just total
         | nonsense, would seem to make the state of mitochondria less of
         | a one-off event and more of the instance of that event we are
         | around at the right time to observe.
        
           | liyamchitayat wrote:
           | Hi! thanks for taking time to read :)
           | 
           | Those other membrane bubbles inside out cells don't have any
           | of the machines we expect to be associated with cellular
           | life- but you never actually know!
           | 
           | Also, this is def not a 1-off, and happened many times,
           | including chloroplasts in this new nitroplast we found
           | https://en.wikipedia.org/wiki/Nitroplast
        
         | aardvark179 wrote:
         | Chloroplasts also evolved from separate organisms and are now
         | effectively organelles. So this is t a one off event.
        
           | ASalazarMX wrote:
           | And even if those hadn't become organelles, who knows if they
           | (or mitocondrias) could have evolved towards multicellular
           | life on their own? They were already organisms to begin with.
        
             | liyamchitayat wrote:
             | Yes! and there are additional cases, like the nitroplasts
             | that we recently discovered.
             | https://en.wikipedia.org/wiki/Nitroplast
        
         | qudat wrote:
         | Like other gradients (heat, pressure, chemical) it might seem
         | rare, the gradient guides its occurrence. A power efficiency
         | gradient was going to happen eventually, accident or otherwise.
        
           | hughesjj wrote:
           | Yup. That it happened isn't by chance, but the particular
           | instance being the one to happen & dominate is by chance.
        
         | hshshshshsh wrote:
         | If reality can emerge out of nowhere I don't see it unlikely
         | for life to emerge in some other planet.
        
           | JumpCrisscross wrote:
           | > _If reality can emerge out of nowhere I don 't see it
           | unlikely for life to emerge in some other planet_
           | 
           | If everything however unlikely is likely because creation is
           | unfathomable, sure.
        
             | hshshshshsh wrote:
             | Not everything. Life in particular. Because without life (a
             | conscious observer) reality cannot exist. So it should be a
             | property of reality for life to emerge.
        
               | thrw42A8N wrote:
               | That sounds like a catch-22
        
               | 9dev wrote:
               | Isn't that kind of mixing up the chain of causation?
               | Without a winner, a lottery cannot exist (or at least, at
               | p=0, it's nonsensical). That doesn't automatically imply
               | there are a lot of winners, however.
        
               | hshshshshsh wrote:
               | I think what I am trying to say is consciousness (life)
               | is reality. And so all kind of planetary experiences can
               | exist inside consciousness as it's contents since
               | consciousness is capable of generating all kind of
               | content.
               | 
               | There is nothing specific about our consciousness that
               | makes it unique to earth.
        
               | timschmidt wrote:
               | You are mistaking the map for the territory: https://en.w
               | ikipedia.org/wiki/Map%E2%80%93territory_relation
        
               | hshshshshsh wrote:
               | Can you explain in simple terms? I see physical reality
               | as almost redundant and consciousness seems to be able to
               | do everything.
        
               | timschmidt wrote:
               | From the first paragraph of the linked article:
               | 
               | "Mistaking the map for the territory is a logical fallacy
               | that occurs when someone confuses the semantics of a term
               | with what it represents. Polish-American scientist and
               | philosopher Alfred Korzybski remarked that "the map is
               | not the territory" and that "the word is not the thing",
               | encapsulating his view that an abstraction derived from
               | something, or a reaction to it, is not the thing itself.
               | Korzybski held that many people do confuse maps with
               | territories, that is, confuse conceptual models of
               | reality with reality itself."
        
               | hshshshshsh wrote:
               | Okay. I can see that in day to day life. People confusing
               | sentences with actual knowing. Like labeling something a
               | tree and thinking you know what a tree is because you
               | know it's a "tree".
               | 
               | But how did anyone verify there is an underlying reality
               | outside consciousness? It's just an assumption right?
        
               | timschmidt wrote:
               | > But how did anyone verify there is an underlying
               | reality outside consciousness?
               | 
               | It's the stuff which continues existing when we stop
               | believing in it.
        
               | dekhn wrote:
               | Yes, it's taken on faith by scientists that we live in an
               | objective universe with cold hard reality outside our
               | consciousness. It seems like a reasonable assumption,
               | consistent with all our observations. It seems not
               | unreasonable to assume that in the early universe there
               | was nothing living, then at some point, through random
               | chance, the first living things became alive (possibly
               | from some non-alive replicators), and then later, the
               | first living things with consciousness came to be. Again,
               | all of this is consistent with our observations, but
               | effectively taken on faith/treated as an assumption.
        
               | dekhn wrote:
               | Your philosophy is consistent with panpsychism
               | (https://en.wikipedia.org/wiki/Panpsychism). Not really
               | clear how this affects the major discussion here, which
               | is about objective reality as determined by science, and
               | so far as we can tell, neither life nor consciousness is
               | not a prerequisite for reality. It's a fun idea to play
               | with but firmly outside the realm of something we could
               | experiment with scientifically.
        
               | dekhn wrote:
               | There is no known scientific principle or theory with
               | experimental support that without a conscious observer
               | reality cannot exist. It's not something that can be
               | tested, and lies in the realm of philosophy, not science.
        
               | hshshshshsh wrote:
               | I don't think reality has this property that what cannot
               | be tested through scientific method is not true.
        
               | dekhn wrote:
               | It might not, you wouldn't be able to convince anybody
               | that something is true, but cannot be tested- that's
               | philosophy and religion.
        
               | WalterSear wrote:
               | A 'quantum observer' is merely a physical system that
               | interacts with the quantum system being measured. It
               | doesn't have to be conscious or animate.
        
         | ricksunny wrote:
         | Robin Hanson #HardSteps
         | 
         | https://m.youtube.com/watch?v=0lKliaFllPA&t=910s (timeatamped)
        
         | VMG wrote:
         | How do we know it only happened once? Maybe it happened
         | multiple times but only one version survived while the others
         | were outcompeted?
        
           | JumpCrisscross wrote:
           | > _How do we know it only happened once?_
           | 
           | We don't. But we know we can't replicate it, have never
           | observed it, don't seem to find half-assed attempts at it in
           | the wild and that there weren't multiple competing
           | chemistries that found themselves co-existing, there was one.
        
         | tasty_freeze wrote:
         | In addition to what others have pointed out (chloroplasts), I
         | think this makes another mistake. Although only the
         | mitochondria and chloroplast lineages remain, it is possible it
         | happened other times but those lineages were out-competed, for
         | whatever reasons, and are now extinct.
        
           | JumpCrisscross wrote:
           | > _it is possible it happened other times but those lineages
           | were out-competed, for whatever reasons, and are now extinct_
           | 
           | Chlorophyll probably outcompeted retinal [1]. (The stuff in
           | our eyes.)
           | 
           | The reduced form of my claim is that mitochondrial life so
           | freakishly outcompetes its competitors as to be in a class of
           | its own. Which still yields a rare Earth, albeit a first
           | among many.
           | 
           | [1] https://en.wikipedia.org/wiki/Purple_Earth_hypothesis
        
             | aydyn wrote:
             | Does it yield a rare Earth? If we didn't have mitochondria
             | and had something say 20% less efficient, why couldn't
             | multicellular life still exist?
        
               | JumpCrisscross wrote:
               | > _why couldn 't multicellular life still exist?_
               | 
               | We don't know the fundamental energy requirements of
               | complex life. The threshold may be 2%. It may be 19.995%.
               | If non-mitochondrial metabolism is common, the Earth
               | would still be rare in that we'd be the "fast" biosphere.
               | The high-octane species. Given how power-intensive
               | intelligence is, that might be material. (Or it might
               | not.)
               | 
               | More fundamentally: we have no plausible alternate
               | chemistries that don't bootstrap on mitochondrial life.
               | (We do for photosynthesis.)
        
               | aydyn wrote:
               | I think that's a little farfetched since a lot of
               | prokaryotes show the beginning stages of complex multi-
               | cellularity.
        
             | jjk166 wrote:
             | In an evolutionary process, one lineage running away is the
             | most likely outcome. It's very unlikely that two competing
             | lineages would evolve to be exactly equal at the same time
             | and remain equal for an extended period of time.
        
               | JumpCrisscross wrote:
               | > _In an evolutionary process, one lineage running away
               | is the most likely outcome_
               | 
               | What are you basing this on?
        
               | quantadev wrote:
               | It's based on the fact that one explanation of why
               | there's not even millions more species of all life, is
               | because the more successful ones simply cannibalized the
               | less successful ones. This would've started even before
               | complex life, almost at the chemical level.
               | 
               | I say cannibalized, because avoiding eating your own
               | species is a higher brain function that would've came far
               | later, so it came down to eat or be eaten. Still is
               | frankly.
        
         | jjk166 wrote:
         | This process, known as primary endosymbiosis, happened at least
         | twice, for mitochondria and chloroplasts. Further, while all
         | chloroplasts (and more widely plastids) appear to share a
         | common ancestor, there is evidence that mitochondria may
         | descend from multiple lineages that underwent lateral gene
         | transfer and/or convergent evolution. Nitroplasts are a likely
         | another, separate instance of primary endosymbiosis.
         | 
         | There is also secondary endosymbiosis, where the endosymbiont
         | organelles of one eukaryote are engulfed and incorporated into
         | another eukaryotic cell to create a new type of endosymbiont.
         | This has happened at least 8 times.
         | 
         | There are also theories that some other organelles are the
         | product of other endosymbiosis events, many of which also have
         | some of the hallmarks like their own genetic material. These
         | theories are more speculative though.
         | 
         | It's also worth noting that while eukaryotes obviously gained
         | some important capabilities from incorporating these
         | endosymbionts, the endosymbionts they incorporated obviously
         | managed to just evolve to perform those functions directly.
         | Further, while one of eukaryotes' distinguishing features are
         | mitochondria, there are several other major differences, and
         | mitochondria are not believed to be what made eukaryotes better
         | able to evolve complex multicellularity. Prokaryotes have
         | indeed evolved multicellularity dozens of times, and we
         | arbitrarily set our definition of complex multicellularity to
         | distinguish from what prokaryotes have achieved.
        
         | UniverseHacker wrote:
         | There are a huge number of different organelles that evolved
         | independently through events like this- other people mention
         | chloroplasts but there are many others, and probably many yet
         | undiscovered.
         | 
         | I would argue that the type of event that produced mitochondria
         | is likely not rare at all, but certain pairings will so
         | outcompete others that we should expect only one to survive and
         | dominate.
        
         | quantadev wrote:
         | All planets with a diverse chemical makeup will stumble across
         | accidental formation of a replicator molecule. It's 100%
         | certain. That's all that's required for "life".
         | 
         | People have theorized even a 50 base pair segment of RNA might
         | be capable of building exact copies of itself, either by
         | snapping in half and auto-forming the same other half, or by
         | other means. Since there's two sexes, it was perhaps a
         | "halving" at that level, that early on, which led ultimately to
         | TWO sexes, but that's a side point.
         | 
         | We can even predict the probability of any 50 base pair
         | ordering. It's 1/(4^50). That's 30 zeroes in the denominator.
         | Now consider that a single glass of water has 10^23 molecules.
         | That's 7 orders of magnitude difference. So the amount of water
         | you need to cross that magnitude threshold is 7. Turns out
         | that's exactly the size of an Olympic swimming pool. 10 million
         | cups of water.
         | 
         | So statistically, a planet with an ocean volume only as large
         | as a swimming pool has the "Statistical Power" (power of large
         | numbers) to find ANY 50 base pair combination (give or take an
         | order of magnitude or two) Once it finds a replicator, life has
         | started, and so has evolution. And that's guaranteed within the
         | first minute or so, at reasonable temperatures. Now multiply
         | that time by the average age of a planet, and you begin to
         | realize, statistically life is guaranteed, in any chemically
         | diverse scenario with reasonable temperatures.
        
           | dekhn wrote:
           | Interesting argument, but nobody believes that a diverse
           | chemical makeup is sufficient to guarantee life.
           | 
           | You can wave big numbers around but none of that makes a
           | convincing argument; it's not hard to construct any number of
           | scenarios where self replicators are started but don't lead
           | to true life.
           | 
           | Also you're comparing a gram of water to a bunch of bases;
           | H2O is not DNA.
        
       | armoredkitten wrote:
       | Talking about what is considered "alive" is an interesting
       | exercise, and shows just how fuzzy those boundaries can be
       | sometimes. But I really don't see how this has any practical
       | impact on how we study mitochondria.
       | 
       | > If we think of mitochondria as non-living organelles, how will
       | we ever harness their full potential?
       | 
       | Whenever anyone uses the "harnessing [its] full potential"
       | cliche, my bullshit alarm starts buzzing. I don't think this
       | article is bullshit, but...we can "harness" as much "potential"
       | as mitochondria have whether we consider them alive or not.
        
       | arcticbull wrote:
       | Feels analogous to the CPU and the Management Engine heh.
        
       | habitue wrote:
       | > If we think of mitochondria as non-living organelles, how will
       | we ever harness their full potential?
       | 
       | "Alive" is a fuzzy boundary in concept space that helps humans
       | navigate a fractally complex world. It's not a fact about
       | mitochondria that either hides or reveals structure. We can
       | harness the potential of viruses, and reasonable people can
       | disagree on whether they are alive.
        
       | roncesvalles wrote:
       | It's such highly unlikely chance events that make me think we
       | really are alone in the universe (we = a sentient civilizational
       | lifeform). There's just no way the long series of extremely
       | improbable events that led to our rise was replicated anywhere
       | else, and it took the sheer vastness of this universe for it to
       | have emerged even once.
        
         | a-curious-crow wrote:
         | universe big
        
         | rsync wrote:
         | There is ~1M bacteria in a single drop of seawater.
         | 
         | Now multiply that by (the ocean) and multiply the interactions
         | by X billion years.
         | 
         | It seems impossible for a symbiosis like this _not to have
         | happened_.
         | 
         | No matter how low the odds are, the counts of those potential
         | interactions bring this outcome to a certainty.
        
           | latchkey wrote:
           | Each grain of sand on earth represents 1 billion planets in
           | the universe.
           | 
           | https://www.reddit.com/r/spaceporn/comments/1af4prs/if_you_w.
           | ..
        
             | Aloisius wrote:
             | There are 100 million times more bacteria in the ocean than
             | there are stars in the universe.
             | 
             | Which really should tell people how rare the development of
             | mitochondria was if it has only happened once here.
        
               | ASalazarMX wrote:
               | It didn't necessarily happen only once; maybe we were
               | left with the most successful instance.
        
               | hughesjj wrote:
               | Not even that. There could be better civilizations than
               | us out there that either
               | 
               | 1. Died off or regressed
               | 
               | 2. Plateaued
               | 
               | 3. Is sufficiently far away or stealthy enough for us not
               | to notice them (whether intentionally or not)
               | 
               | I've often thought about the whole communications bubble
               | argument... I don't buy it. I'd imagine, like wifi, other
               | civilizations will maximize their communication
               | bandwidth, which essentially also maximizes entropy which
               | looks like noise to us. Compression, encryption,
               | redundancy, multiplexing over frequency and amplitude and
               | time, directional antennas and signalling... That's what
               | we've done in under 100 years.
               | 
               | I know there's stuff like organic markers etc, but if
               | machines are doing most of the heavy lifting I don't
               | think that would matter. Same with stuff like hydrogen
               | emissions lines. Whatever is abundant will be used for
               | "settled" and "dead" solar systems alike.
        
           | dylan604 wrote:
           | The issue here is that the interactions over X billion years
           | are not the same. Each event that happened on this rock would
           | also need to happen else where to have the same evolutionary
           | pressures applied.
        
           | crazygringo wrote:
           | > _No matter how low the odds are, the counts of those
           | potential interactions bring this outcome to a certainty._
           | 
           | That is simply not true. Events are classified by
           | probabilities, and there are a whole lot of things with a
           | probability _a lot less_ than will happen across the whole
           | ocean across however many billion years.
           | 
           | All the higher-probability events will occur, yes. But a
           | specific _sequence_ of multiple extremely low-probability
           | events? That then continues to replicate before it gets wiped
           | out by chance?
           | 
           | Not a certainty, absolutely not. Contrary to what you say, it
           | matters _very much_ exactly how low the odds are.
        
         | dumbfounder wrote:
         | The universe seems so ridiculously big to me that I can't
         | imagine anything major happening only once.
        
       | rawgabbit wrote:
       | Here is an animation of the Mitochondria in action. The
       | mitochondria has two cell membranes. The gap in between is called
       | the intermembrane space. It is also positively charged with
       | protons. There are complexes 1-4 which continuously pump protons
       | into this space. The ATP synthase molecule harnesses these
       | protons, similar to a water wheel harnessing the flow of water,
       | to make ATP which is the energy molecule the cell uses.
       | 
       | https://youtu.be/LQmTKxI4Wn4?si=i7TpeoV3o_mCWpZF
        
       | jessriedel wrote:
       | This article managed to hit two classic science journalism
       | cliches in just the first few paragraphs.
       | 
       | (1) "Someone hypothesizing a very dramatic theory with weak
       | evidence was considered wrong by most colleagues but later
       | vindicated when strong evidence emerged". (No mention of
       | thousands of other dramatic hypotheses that turned out wrong.)
       | 
       | (2) "You may have heard in unsophisticated popularization that
       | [philosophical claim ultimately hinging on semantic distinction]
       | was false, but really it's true [assuming my preferred
       | semantics]".
       | 
       | Aren't we all tired of this yet? Aren't science journalists
       | embarrassed by this stuff?
        
         | asveikau wrote:
         | For #1, I disagree with how you assess this.
         | 
         | Firstly, the one who makes the logical fallacy inference that
         | this implies all or most dramatic hypotheses are true is ...
         | You. Not the author of the article. The author of the article
         | is only talking about one specific theory. If I tell you a
         | story about a chicken crossing the road, I'm not obligated to
         | tell you about all the chickens who don't cross any roads.
         | 
         | Second, there are plenty of examples of established theories
         | that started this way, and so it _is_ important that scientists
         | consider controversial hypotheses with an open mind. Speaking
         | in any context, it 's very easy to dismiss evidence that
         | contradicts your views prematurely. It's sort of a defense
         | mechanism we all do. It's important to recognize such a bias
         | and be willing to acknowledge where your own theory could fall
         | short when you see it.
        
           | jessriedel wrote:
           | My point isn't that these can't be interpreted correctly,
           | it's that these framings teach us nothing new because they
           | have been repeated a thousand million times and this article
           | does not attempt to go beyond the superficial cliche.
        
         | liyamchitayat wrote:
         | Hi! for point 2# I had many debates about this with Prof. that
         | are cell biologists, and if you google "Are mitochondria
         | alive," the answer Gemini will give you is no. This is very
         | controversial in my academic circles, but I appreciate your
         | thoughts!
        
           | jessriedel wrote:
           | My point is that it's largely a semantics dispute, not a
           | scientific one.
        
       | robwwilliams wrote:
       | Wonerful! This article is a mind-meld of Humberto Maturana's work
       | on autopoiesis with almost any of Nick Lane's deep discussions of
       | bioenergetics e.g., the wonderful book " Power, Sex and Suicide:
       | Mitochonria and the Meaning of Life" or his equally strong book
       | "Transformer: The Deep Chemistry of Life and Death" that is
       | focused on the Kreb's cycle. He brings biochemistry and
       | bioenergetics alive in a way that will impact your thinking.
       | 
       | Maturana and Valera gave a brilliant definition of "living" in
       | Autopoiesis and Cognition: The Realization of the Living" (1980).
       | But their writing style will make this a tough read. Terry
       | Winograd write a useful summary if Maturana's philosophy in his
       | computer science classic "Computers and Cognition".
        
       | meneton wrote:
       | This article is framed as if there is something novel and
       | profound here, but the "aliveness" of mitochondria is simply a
       | matter of how we choose to apply the label "life" - a human
       | linguistic construct that exists independently of the biological
       | phenomena. This is not a new discussion - science has been
       | considering this question for many decades, just as it has with
       | viruses. These all come down to arguments about semantics and
       | don't add anything to the science.
       | 
       | Mitochondria are fascinating and there is still a huge amount to
       | learn about them but they are totally dependent on the cell's
       | machinery. Most of their genes, the code for their structure, are
       | in the nuclear DNA. A glaring omission if you are trying to make
       | the case that mitochondria are independently living. My heart can
       | exist independently of me, and be transplanted into other people,
       | but does it mean that it is alive?
       | 
       | The implication of the whole article is that there something we
       | have missed. This really isn't the case. Lynn Margulis's
       | endosymbiotic origin of mitochondria was challenged by many, and
       | it did spark a scientific debate - that's how science works. She
       | won the argument comprehensively decades ago and is well
       | established science. There have been many such endosymbiotic
       | events in the history of life - there are subfields of
       | evolutionary biology that study these processes.
        
         | liyamchitayat wrote:
         | Hi!
         | 
         | I agree with you, which is why I wrote this- but if you google
         | "are mitochondria alive" gemini says it isn't. And yes, the
         | cells in your heart have an effective and potenitial niche!
         | 
         | We seem to have many tools to engineer viruses, but few to
         | engineer mitochondria- perhaps considering them as alive could
         | change that!
        
           | tim333 wrote:
           | I just tried that and it said:
           | 
           | >Yes, mitochondria are alive, though they are not considered
           | "living" in the same way as a cell because they can't
           | function independently...
           | 
           | Maybe it's learning!
        
             | jpk wrote:
             | Or maybe the temperature is set too high! Probably don't
             | start with a single LLM response as the basis for your
             | understanding of scientific consensus.
        
             | UniverseHacker wrote:
             | Eukaryotes generally can't survive without mitochondria
             | either. It seems silly to discuss if different subsystems
             | in a living organism are independently "alive." It's a bit
             | like arguing if just the wings or just the engine of an
             | airplane are flying machines.
        
           | dragandj wrote:
           | "Gemini" says? So what?
        
             | tim333 wrote:
             | It shows there are misconceptions out there, if only in
             | LLMs.
        
           | satvikpendem wrote:
           | I am not sure you should be relying on an LLM as any
           | indication of anything...
           | 
           | More seriously, considering something as being alive in order
           | to engineer them better does not necessarily change the fact
           | of them actually being alive or not, in my opinion.
        
             | dekhn wrote:
             | If LLMs work the way I understand them to, they are trained
             | on large corpora which contain a statistical preponderance
             | of statements which are consistent with the current
             | scientific mainstream, so it may not be completely crazy to
             | try doing this; you'd get the scientific mainstream
             | explanation, and possibly a few alternative hypotheses if
             | they had enough literature support.
        
           | JumpCrisscross wrote:
           | > _if you google "are mitochondria alive" gemini says it
           | isn't_
           | 
           | And my grandmother is a bicycle.
        
             | mock-possum wrote:
             | Still one of my favorite idioms
        
           | meneton wrote:
           | You are completely right that we should be thinking far more
           | creatively about manipulating mitochondria. There are a lot
           | of diseases (including Covid) that have mitochondrial
           | aspects. I just don't think calling them alive helps, other
           | than to get you some decent exposure on HN :)
        
         | sroussey wrote:
         | Mitochondria are weird. Look at 3-parent baby (human).
        
         | aeturnum wrote:
         | > _The implication of the whole article is that there something
         | we have missed._
         | 
         | I think this article is talking to people who haven't
         | internalized the details of the scientific consensus. Those
         | people are still going around, talking about "life" and making
         | decisions based on the flawed understanding this article is
         | critiquing. I think it's likely that the thing that "has been
         | missed" is not narrowly scientific in the way you seem to be
         | thinking - but more about broad implications and worldview.
        
         | thinkling wrote:
         | > Most of their genes, the code for their structure, are in the
         | nuclear DNA.
         | 
         | Are they? I was under the impression that mitochondria are
         | closer to pseudo-cells living inside human cells.
         | 
         | Wikipedia seems to confirm this [1]:
         | 
         | > Although most of a eukaryotic cell's DNA is contained in the
         | cell nucleus, the mitochondrion has its own genome
         | ("mitogenome") that is substantially similar to bacterial
         | genomes.
         | 
         | [1] https://en.wikipedia.org/wiki/Mitochondrion
        
           | kylebenzle wrote:
           | OP above you is correct. Maybe you are thinking about it
           | wrong?
        
           | bonzini wrote:
           | See below on Wikipedia: "Most proteins necessary for
           | mitochondrial function are encoded by genes in the cell
           | nucleus and the corresponding proteins are imported into the
           | mitochondrion. The exact number of genes encoded by the
           | nucleus and the mitochondrial genome differs between
           | species."
        
           | ale42 wrote:
           | There's a specific page on Wikipedia about Mitochondrial DNA
           | [1], where it is clearly said that:                 In the
           | cells of extant organisms, the vast majority of the proteins
           | in the       mitochondria (numbering approximately 1500
           | different types in mammals) are       coded by nuclear DNA,
           | but the genes for some, if not most, of them are
           | thought to be of bacterial origin, having been transferred to
           | the eukaryotic       nucleus during evolution. (citing [2])
           | 
           | [1] https://en.wikipedia.org/wiki/Mitochondrial_DNA
           | 
           | [2] https://doi.org/10.1016%2Fj.cels.2016.01.013
        
           | 725686 wrote:
           | They were, originally. Over the eons, they have lost many of
           | their original genes. Source: Nick Lanes fantastic books,
           | specially Power, Sex, Suicide
        
         | dekhn wrote:
         | what about obligate intracellular parasites like mycoplasma?
         | They are awfully close to mitochondria but we think of them as
         | alive. They've lost many of their genes and can't survive
         | without the host. Looking at those, you could almost see a path
         | from an obligate intraceullular parasite to an organelle
         | derived from a phagocytosed prokaryote.
        
         | beambot wrote:
         | > These all come down to arguments about semantics and don't
         | add anything to the science.
         | 
         | This accurately describes much of science...
         | 
         | > My heart can exist independently of me, and be transplanted
         | into other people, but does it mean that it is alive?
         | 
         | The cells that comprise your heart are very much alive, but
         | they will die without support infrastructure. They live, they
         | replicate, they die -- like every cell in your body. If I
         | relocate you to the moon without support infrastructure, you
         | would die too -- and yet (I think?) you are probably alive.
        
           | staplers wrote:
           | Best argument I've heard for Gaia theory, intentionally or
           | not.
        
       | lynguist wrote:
       | I agree completely with all the points made in the article and
       | would double down on the critique of the philosophy of biology as
       | a discipline and science itself: namely that is has historically
       | evolved as a mere system of typologies and that this is so
       | settled in and so sacrosanct that biology is such a superstition
       | with human-made categories a couple hundred years ago and not a
       | real science.
       | 
       | We see the exact same things also when discussing what is a
       | species and also completely disregarding the reality of
       | horizontal gene transfers etc in the strict, traditional trees.
       | 
       | The models are quite wrong and even reduced wrong.
       | 
       | There is this one famous article that shows how traditional
       | biology would go and analyze a transistor radio, namely just
       | label its assumed components!
       | 
       | Here is the discussion:
       | https://news.ycombinator.com/item?id=31697757
        
       | tim333 wrote:
       | I'd been taught mitochondria maybe came from bacteria back in
       | high school 40 years ago but I didn't realise till now that Lynn
       | Margulis also proposed the cell nucleus arose in a similar way.
       | 
       | (paper https://pmc.ncbi.nlm.nih.gov/articles/PMC34369/)
        
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