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Mitochondria Are Alive

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Re: Mitochondria Are Alive

#241

Post by 725686 »

thinkling wrote: post #222
meneton wrote: post #179

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 sem…

> 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.w…

They were, originally. Over the eons, they have lost many of their original genes. Source: Nick Lanes fantastic books, specially Power, Sex, Suicide

Re: Mitochondria Are Alive

#242

Post by aydyn »

JumpCrisscross wrote: post #201
aydyn wrote: post #198

Earlier quoted context omitted.

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?

> 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…

I think that's a little farfetched since a lot of prokaryotes show the beginning stages of complex multi-cellularity.

Re: Mitochondria Are Alive

#243

Post by adastra22 »

ssalka wrote: post #20
adastra22 wrote: post #14

I don’t understand the headline (yes I skimmed the article). Why would mitochondria not be alive? What does that even mean?

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.

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.

Re: Mitochondria Are Alive

#244

Post by quantadev »

JumpCrisscross wrote: post #78

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 chimeræ the first mitochondrial cells would have been. Until mitochondria, the emergence of l…

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.

Re: Mitochondria Are Alive

#245

Post by dekhn »

satvikpendem wrote: post #204
liyamchitayat wrote: post #185

Earlier quoted context omitted.

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!

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.

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.

Re: Mitochondria Are Alive

#246

Post by quantadev »

JumpCrisscross wrote: post #224
jjk166 wrote: post #218

Earlier quoted context omitted.

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.

> In an evolutionary process, one lineage running away is the most likely outcome What are you basing this on?

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.

Re: Mitochondria Are Alive

#247

Post by dekhn »

quantadev wrote: post #244
JumpCrisscross wrote: post #78

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 chimeræ the first mitochondrial cells would have been. Until mitochondria, the emergence of l…

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 tha…

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.

Re: Mitochondria Are Alive

#248

Post by dekhn »

pieter_mj wrote: post #150
outworlder wrote: post #86

Earlier quoted context omitted.

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 organism…

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 r…

uhh where did you get " Mitochondria are the software that epigenetically switch nuclear DNA genes on and off."

Re: Mitochondria Are Alive

#249

Post by staplers »

beambot wrote: post #233
meneton wrote: post #179

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 sem…

> 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…

Best argument I've heard for Gaia theory, intentionally or not.

Re: Mitochondria Are Alive

#250

Post by w10-1 »

Key fact (left out of the article): most of the mitochondria's essential proteins, including those for ATP/energy synthesis, are produced by the host cell from the host cell's DNA. So yes, mitochondria have some DNA and do replicate, but no, their cell is not just an "environment" for them.

Also interesting: mitochondria can join (often to rescue one failing due to transcription errors) and be transported to other cells across bridges (to supercharge the recipient, as they want to do now for immune cell therapy).

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