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Mitochondria Are Alive

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Re: Mitochondria Are Alive

#401

Post by adastra22 »

Teever wrote: post #389
adastra22 wrote: post #332

Earlier quoted context omitted.

Because bringing up “what about Y?” When the discussion topic is X and there is no connection to Y goes against HN norms.

But there is a connection between the X and Y in this case. One is a subset of the other. We're talking about the same thing man, I'm just making the point that I feel that there should be greater emphasis on the subset. Look at the top thread in this post, people are doing a very similar thing. I truly think that the pop-sci interest in mitochondria stems from the nickname and for no other reason and to me that's a…

Ribosomes and mitochondria are not the same thing.

Re: Mitochondria Are Alive

#403

Post by quantadev »

QuiteSocialized wrote: post #399
quantadev wrote: post #244

Earlier quoted context omitted.

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…

For this to hold, each of those water molecules in that swimming pool needs to somehow turn into a random 50 base pair chain of RNA. Those RNA molecules are also going to be ~two orders of magnitude larger than a water molecule, so you're going to need a bigger pool... To actually replicate, some loose ingredient molecules must also be present, and in reasonable quantities to be at hand in any given place in the pool…

That's a decent analysis of the things this "thought experiment" doesn't address. I'm not a chemist but I think in a sea of AT and GC pairs even mixed with water, the ability to find every random sequence possible is near certainty:

Especially when you multiply by the number of swimming pools of all ocean water (10^14) by the number of minutes of the history of Earth (10^15), and consider that the probability of the accidental 50 base pair replicator forming needs to have those 29 extra zeroes, in the numerator (not the denominator). So the likelihood, now that I add more info, has just gone up 29 orders of magnitude. lol. (BTW. the 1 minute assumption will be temperature dependent, and is a guess at how long it takes reactions to take place).

The whole thing is a rough approximation like the Drake Equation is, and each number is an estimate. If you want to attack the Thought Experiment, at it's weakest point, just question the initial assumption, which is the biggest guess of all, that some unique 50 base pair RNA can replicate itself.

Re: Mitochondria Are Alive

#404

Post by larkost »

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.

Outside of a host cell viruses do not fit any of the definitions of life: - they do not seek or consume sources of nutrients or energy - they do not have a metabolism - they do not grow

In fact the only place they fit the definition is reproduction, and that is only through the machinery they commandeer from the cells they infect.

To me viruses clearly do not fit the definition of life. But fire... that is hard to exclude from the definition without some mental contortions. I am not advocating that fire is alive for any useful reason, but it is hard to exclude from the definition.

Re: Mitochondria Are Alive

#405

Post by Teever »

adastra22 wrote: post #401
Teever wrote: post #389

Earlier quoted context omitted.

But there is a connection between the X and Y in this case. One is a subset of the other. We're talking about the same thing man, I'm just making the point that I feel that there should be greater emphasis on the subset. Look at the top thread in this post, people are doing a very similar thing. I truly think that the pop-sci interest in mitochondria stems from the nickname and for no other reason and to me that's a…

Ribosomes and mitochondria are not the same thing.

Agreed. Ribosomes are a subset of mitochondria.

Re: Mitochondria Are Alive

#406

Post by adastra22 »

Teever wrote: post #405
adastra22 wrote: post #401

Earlier quoted context omitted.

Ribosomes and mitochondria are not the same thing.

Agreed. Ribosomes are a subset of mitochondria.

Neither one is a subset of the other. I think you are very confused about your microbiology. I'm not going to continue this conversation.

Re: Mitochondria Are Alive

#407

Post by Teever »

adastra22 wrote: post #406
Teever wrote: post #405

Earlier quoted context omitted.

Agreed. Ribosomes are a subset of mitochondria.

Neither one is a subset of the other. I think you are very confused about your microbiology. I'm not going to continue this conversation.

https://en.wikipedia.org/wiki/Mitochondrial_ribosome

Re: Mitochondria Are Alive

#408

Post by Mali- »

jessriedel wrote: post #153

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 cl…

Perfectly put

Re: Mitochondria Are Alive

#409

Post by jjk166 »

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?

The second sentence of the comment.

Re: Mitochondria Are Alive

#410

Post by jjk166 »

Symmetry wrote: post #354
jjk166 wrote: post #205

Earlier quoted context omitted.

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…

The first time it happened involved a huge number of changes in the host cell, like the creation of a nucleus. That makes it seem more likely that an already eukaryotic cell can more easily incorporate other endosymbiotes. Observation of prokaryote/prokaryote endosymbiosis would be real evidence against the rise of eukaryotes being the or one of the main limitations in the number of intelligent species in our galaxy.

There's really only one change that mattered - phagocytosis. The ancestor of all was a prokaryote that practiced phagocytosis, the process of engulfing other cells. Endosymbiosis resulted from some of these engulfed cells not being digested.

There are no known modern prokaryotes capable of phagocytosis. Presumably the extinct prokaryotes who were capable, including those from the same lineage as the eukaryotes but which did not pick up mitochondria, were outcompeted by the eukaryotes who occupied the same niche.

Other changes like the origin of the cell nucleus and many other organelles can be readily explained by other malfunctionings of the phagocytosis process. Basically once you have the ability to pinch off parts of your cell wall into internal structures, you suddenly get a bunch of internal structures made of stuff that look surprisingly like cell wall.

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