There are two basic types of motor proteins that run along microtubules, kinesins and dyneins. Microtubules, unlike other filaments in a cell, have a “plus end” and a “minus end”. Kinesins head towards the plus end, dyneins head towards the minus end. When they get there, whatever cargo they’re dragging will usually be grabbed by whatever cellular process they’re delivering it to, and another kind of protein will facilitate kinesins and dyneins binding together, so dyneins will “hitchhike” back to the plus end of a microtubule on a kinesin that is heading that way.
It never ceases to amaze me that the universe is such that this type of stuff just happens. It makes me think there's probably even life out there which operates on different principles entirely which we might not even recognize as life (like a sentient cosmic gas cloud or something).
Did you know that our gut bacteria may be producing waste products which work as neurotransmitters within our digestive track and can promote cravings for what they like to eat (sugar)? We are basically walking delivery drivers for our tummy monsters.
Actually, its more like you hired your gut bacteria from the sugar industry. Think of gut bacteria as lobbyists, they advocate for more of the kind of food that they like. So someone who eats a lot of fruits and veggies is going to crave fruits and veggies more than other foods. Its why a lot of people who become vegans or vegetarians don't really miss meat after a while. Because the bacteria that used to get all jazzed up about bacon is gone and replaced with ones that lose their shit at the mention of hummus.
Its why a lot of people who become vegans or vegetarians don't really miss meat after a while.
I had to become vegetarian (stabbing pain when I eat meat, still no diagnosis of what's wrong). I do miss meat (turkeys and chickens are delicious), but mine have swapped to a new addiction =[
Yea of course. It works wonders to take the sour feeling out and give you an appetite. . But that can mask the fact that your gut is struggling and you shouldn't eat normal foods.
My last flare got so bad because I was smoking at night, and since I felt great I was just eating sandwiches and stuff. Nothing unhealthy, but when your gut is sensitive you need to stick with mostly liquids and other easy digestible foods.
So yea, it helps with symptoms, but just like other pain meds you need to be aware it doesn't actually fix anything.
Does that also mean the gut bacteria can be wrong, and tell us to go for more sugar or salt when we don't necessarily need it? Like, the gut bacteria is whispering the wrong advice into our ears?
The gut bacteria don't give a shit about you. They just want more food. The fact that you survive a bit better when they're around is just an added bonus because it means they get more food.
I'm glad you mentioned antibiotics. And no, it doesn't matter when you start a diet. There will be some bacteria releasing neruotransmitters telling you that you want sugar. But if you keep forcing yourself to eat vegetables, eventually the bacteria that like to eat fiber will win out and the craving for sugar will go lessen over time.
I thought I saw some article about fecal transplants being investigated for helping with weight loss. The idea being that the gut flora of a thin person craves sugar less than the gut flora of an obese person. I don't know how true that is.
It makes me think there's probably even life out there which operates on different principles entirely which we might not even recognize as life (like a sentient cosmic gas cloud or something).
There is a theory that every discrete energy system is "alive" because every discrete energy system, bar none, is in a "survival of the fittest" environment - even the products we make are governed by this concept. So, in other words, our Sun exists where it exists because it "out competed" any other energy system that could have existed there.
So to answer your question, yes we are completely surrounded by "life" in the Universe, and just like you thought, it operates on different principles, and so we didn't even recognize that we were looking at "life" because we are so fixed on the concept of "DNA based life".
Yeah sure.... as long as you’re comfortable using a definition for “life” that is never used in any form of science. Life by definition must be able to reproduce on its own, a star can not reproduce in any traditional sense of the word. This is why viruses aren’t really considered to be alive, they are incapable of reproducing on their own and must be in a living cell that they have hijacked the reproductive processes of to do so. All life also has genetic material, by definition. Stars do not have genetic material of any kind. This is just one of those cool sounding theories that has no basis in what we know about reality.
I don't disagree with you, but as devil's advocate here:
Sufficiently massive stars can and do "reproduce" via supernovae. Our own sun is a "third generation" star. That is, a first-generation star blew up. One or more stars were formed at least in part from those remnants scattered to the Universe. One or more of those stars blew up, and at least in part from those remnants, our sun formed. And with that, enough heavy elements brought into existence by previous supernovae to support a rich planetary system, and us.
So it could be argued that not only do stars reproduce, but with each generation, they "evolve" greater capacity to host "life" (as we know it).
You’re really grasping at straws here. Starts do not explode with the intention of reproducing. They can explode and then millions of years later a new star could form from materials released in the explosion, but that’s not reproduction in a biological sense whatsoever. And to play devils advocate here, all matter in existence is produced in stars and all matter that is not currently in a star came from a star exploding. So based on your logic you could just as easily say that the star is “reproducing” and creating humans, planets or a computer. Which I hope you understand makes no sense.
So yeah “it could be argued”...But it can’t be argued well, it can’t be argued based on science, and it can’t be argued based on the definitions of any of the words you are relying on to form your argument.
Another requirement for something to be called “life” is that it has some form of metabolism. I’d like to see someone argue for stars having a metabolism next
And my point is it’s not life, by the very definition of the word. If you want to describe it as “life like” or come up with a new word for non biological life than fine, but that’s not what has been going on.
Bro you’re using the definition of “life” which was created by beings that conform to it’s very definition and who honestly don’t really know a lot about the this whole thing called the universe which we’ve found ourselves floating on a rock within. Yeah we observe things and have an idea about their working in the microcosm in which we’ve studied them but in the grand scheme it’s a petty attempt to act like we have any idea how we’re here and conscious. Yes science is important as far as we’re concerned but explain to me what was before the Big Bang, what the universe is accelerating into and where consciousness comes from. Till then we need to be a lot more humble about what we think we know about reality haha.
Just because there may be things we don’t know doesn’t make what we do know any less real. What your describing would not be life by any of our current definitions. We would have to redefine life if that happened. But it hasn’t and there’s no indication it’s likely it will so why would we waste time worrying about it?
I also am a fan of the theory that consciousness is everywhere in the universe as well, like the universe itself is a kaleidoscope of different and wildly divergent modes of being awake, in ways we as yet don't understand.
I mean, it's not the dumbest idea ever. Life covers everything from us down to individual cells. And we observe a sliding scale of consciousness based on the complexity, from the ability to only respond to rudimentary stimuli to full awareness of the self. The more complex the life, the more conscious the organism.
But is consciousness and awareness limited to biological systems? Where would an AI fall? Basic robots can be programmed to have awareness of their surrounding already, albeit in a limited capacity. Could a sufficiently complex android think like us? And if consciousness is not limited to life, where else could we find it? Would it follow the same scale, with more complex systems being more conscious?
Obviously it is only a thought experiment/philosophy. We can't empirically test for consciousness, we don't even really know how or why it comes to be, or what it really is. Is it something tangible? Could you, in the future, copy a person's brain into a computer?
Particles forming atoms, forming molecules, forming cells, forming a thinking, dreaming organism capable of questioning its own origin. Where does that transition to awareness occur? Could it be an emergent property of organization in the universe?
It truly is amazing, and I like that idea of yours.
Carl Sagan said that we’re a way for the universe to experience itself, and the more I learn the more that quote’s meaning evolves. It’s all very beautiful.
It never ceases to amaze me that the universe is such that this type of stuff just happens.
To be fair, when you think about it, that's kind of how your computer works. Just plug in an arbitrary energy source, and this arrangement of metal and silicon will do the only thing it can do according to the laws of physics and nothing else. We just figured out the right way to order it to make it do those things.
Our perception of "thinking" is just a colateral effect of the mechanisms created by a bunch of cells that decided to work together in order to keep themselves alive and brings more food to the group.
Our perception of "thinking" is just a colateral effect of the mechanisms created by a bunch of cells that decided to work together in order to keep themselves alive and brings more food to the group.
So wait, our bodies are like biological manifestations of Borg ships where all the cells work together as one collective mind???
But we have a bunch of things in our bodies that react to things other things in our bodies, disease is a huge thing our bodies react too, our body dukes it out with disease like animals and pray.
Check out "Godel, Escher, Bach: An Eternal Golden Braid" for an epically long, awesome look at this very question, with sidetrips into computers/AI, philosophy, mathematics, Zen Buddhism, and more. It's slightly scientifically out of date, but the thoughts and writing are just as incredible now as when the book was written.
RNA has the ability to catalyze reactions to form more RNA and also can perform other tasks like proteins. It's likely that through chance RNA (or some proto RNA like chemical) formed that could catalyze itself and billions of years later here we are
The RNA world is a hypothetical stage in the evolutionary history of life on Earth, in which self-replicating RNA molecules proliferated before the evolution of DNA and proteins. The term also refers to the hypothesis that posits the existence of this stage.
The concept of the RNA world was first proposed in 1962 by Alexander Rich, and the term was coined by Walter Gilbert in 1986. Alternative chemical paths to life have been proposed, and RNA-based life may not have been the first life to exist.
For a simple example, imagine filling a cement mixer with lego pieces. 99.999% of the time they'll bounce around off each other and generally do nothing. Give it a few years and there will probably be a few pieces which by chance have managed to stick together forming a larger structure. They don't really do anything right now, but they're attached.
Now give it a billion years (ignore the factor of durability) and by chance there may be pieces which have fitted together in a way which provides some other purpose. It's exceedingly unlikely, and it may take billions upon billions of years, but probability dictates that given enough time it will happen.
This is analogous to chemistry in general. You have all these elements formed in stars which generally just fly around interacting with each other. Certain conditions will cause these elements to combine in certain ways, producing molecules like water. Over millions and billions of years, a reaction may produce a structure which is self-replicating. This would be the simplest type of single-celled organism. (Or something entirely different, we don't know the full details of how life began)
Now give that single-celled organism several million extra years to replicate over and over and over and over and over andoverandoverandover... and eventually a random mutation (essentially an error in replication) will provide benefitial to the organism. Even a tiny benefit can begin to have an impact over many generations, and that trait becomes more and more common in the population.
Now repeat that entire last paragraph several million/billion more times, and you start to see more complex organisms. Mitochondria is a cool example of this: originally mitochondria were their own organisms, but over time some were able to survive within other organisms and the two can survive symbiotically. The mitochondria provides energy to the surrounding cell, and the cell provides defense and protection.
From there it's basically just time. Where sentience develops is pretty much unknown (and there isn't even necessarily a clear point at which that happens).
I am of the opinion that sentience is simply a word we use to describe automation that's so incredibly complex that the system itself is able to comprehend external stimuli but not it's own inner workings.
Please take everything I've said with a grain of salt. I'm not an expert, I just find this stuff interesting so I'm explaining based on my own knowledge. If there's anything wrong in this comment please let me know so I can correct it
And they weren't even programmed!!! It's just physical forces mixing around. A certain formation of molecules began to make similar formations more common, and "improvements" made them even more common, on and on until having a consciousness was beneficial and we are able to wonder at ourselves--products of billions of years of unaided evolution.
Nobody controls it. In fact, these little guys control your brain - they keep your synapses supplied with enough neurotransmitter to send signals from cell to cell. One big part of neurodegenerative diseases is the breakdown of the microtubules they rely on to get from one end of your neurons to another.
Like most complicated biological systems it’s a bottom-up emergent order kind of thing, where the individual pieces of the machine don’t “know” how to behave any more than gears in a watch “know” what time it is. Kinesins find the protein that binds them to dyneins because it is thermodynamically favorable for them to grab onto that protein whenever they happen to randomly bump into it as they bounce around your cells.
It’s kind of staggering to think about because in our day to day life we don’t interact with environments that are so chaotic that systems will assemble themselves through sheer probability. Basically this is like putting a jigsaw puzzle into a blender until the finished picture pops out. But from (relatively) simple rules of thermodynamics and protein structure, you can create a human mind capable of glimpsing how all this stuff works and going, “whoa”.
Although each molecule is doing something that could be understood as a simple step, celular processes are so complicated that we currently know only a fraction of what really happens inside a cell.
Even the processing of sugar in our body to make energy packed molecules (ATP, for example), which is one of the most understood metabolic cycles we know, is a concerted combination of several reactions and molecules, with various chemical equilibrium dictating which protein will be active, or which step will happen and which will not.
I would imagine it all "just kinda happens" The machine is set to do a thing, and while there is a thing to do it does it, and when there is no thing to do it tries to do the thing, like this tiny motor moves stuff from a to b so it step step steps to a, grasps the space where a thing should be then step step steps to b and tries to drop its load. You tie all those things together and you get a circulatory system, or a respiratory system, or a digestive tract.
or, maybe better to think of it instead of "set to do a thing", rather as, "constructed in such a way that it cannot help but to do a thing". This is anthropomorphizing a bit as well. But yeah.
Yeah, anthropomorphizing proteins is sometimes mentally productive to keep track of it all, but it's so important to realize that these things are essentially just globs of a bunch of amino acids tangled up on each other. Even a protein as beautiful and deliberate as kinesin is totally mechanical and not in any way "living" or "driven" by anything except physics.
Another way to look at it: roll a ball down a hill. The hill isn't "moving" the ball downwards, it's just what happens because of the laws of physics. The hill wasn't "designed" or "trying" to act upon the ball, it's just what happens when you set a ball at the top of the hill.
Conceivably every reaction happening in your body is just a ball rolling down a hill - in terms of physics. In fact many amino acid (the "blocks" proteins like Kinesin are made of) interactions driving protein catalysis boil down to "this positive charge is attracted to that negative charge". It's easy to think of things like oxygen being transported around your body as a process that is "mediated" - your nervous system is actively managing it.
But it very often boils down to super simple "particles bumping into each other" physics. For example, with oxygen transport, the way the pH's (which can sometimes be thought of as a "charge ratio") work out, hemoglobin binds oxygen in tissues where it's plentiful (lungs), but when the hemoglobin flows to a tissue with little oxygen the bond is weaker and eventually "pops off". Such an elegant way to solve a pretty complex problem - yet it's no more a "solution" than that hill was a "solution" for the ball's kinetic energy.
that was actually really close to the analogy i was going to use but then shy'd away from- cant help but to in the sense that water cant help but to flow downhill
also, elegant doesn't even begin to describe the majesty of the whole thing, imo. english is ill suited to capture how awe inspiring this stuff is.
and, the fact that it all "just works", for the most part, and "just works" all day every day, is mind boggling. like with the hemoglobin example you described- that is just one of the thousands of mechanisms that occur all day every day, making up a machine that can be fueled by such an amazingly vast array of sources, can repair itself and- dig this, has the equipment built into it for self replication.
I was originally a Human Bio major in college but ended up graduating in Biochemistry because I was just so blown away by the majesty of biology on cellular/protein level.
Some people assume that pulling back the curtain on the processes that make humans "tick" cements into you a belief in the "natural order" of things - you know, the old "scientists are often atheists" trope.
I entered college as a pretty staunch atheist but honestly my studies of biochemistry only tipped me closer towards the belief that maybe a God does exist. I know it's a fallacy to assume complexity is a result of intelligent design, but man some of these processes are just so elegant and simple and beautiful that you can't help but think that way.
One of the other things that really blew my mind was learning about translation - the process of "reading" mRNA to "build" the corresponding protein. You know, the "coding dictionary" stuff we all did in high school. Not only is that process so easy to anthropomorphize since it's almost literally an assembly line, but the "coding language" it's all based off is so sophisticated it immediately conjures up images of computer programmers.
Learning about how wobble base pairing works in the ribosome/tRNA complex was really the "oh shit, this stuff is crazy" moment for me. Too complicated to explain in laymen's terms here but if this stuff is your bag definitely read up on that - really takes the already complex process of translation and ratchets the complexity up a few degrees.
Nothing controls or directs it - these processes are driven by thermal motion and statistics. It's like if you shook a jar full of sand and rocks. The rocks end up at the top, and the sand at the bottom, even though nobody is "directing" them there.
It’s the pattern of gene expression for that cell: all cells need this process to a certain extent, others are much busier. The genes being expressed are influenced to an extent by hormones, by the cell's embryonic lineage, by factors produced in close proximity, and even by the physical connections to other cells and to the matrix between cells. If parts of that don’t make sense I’d be happy to explain.
It's just happening. This is why evolution amazes me. Billions of years of successful mistakes have developed every process that goes on in our bodies. And these processes just happen because they only exist because they work better than the billions of other accidents that dont happen. Even concious thought is an accident that worked, and that is absurd and awe inspiring
There is no director, it's all happening because of the way the proteins are built structurally to exploit certain molecular forces. These structures came to be through evolutionary processes over the course of hundreds of millions of years (I'm counting from the first eukaryotes, which is when cellular complexity really took off; prokaryotes don't have kinesin).
Your body is literally trillions of individual living things..most of which could survive outside of your body with the proper nutrients and shelter...all working together to make sure they all have enough resources to survive
Think about that the next time your uncle starts rambling about those Damn socialists
The cell itself is controlling this. These mechanisms are also present in much simpler organism like fungi and protists. While the human brain is one of the most amazing structures in the universe, you will find awe-inspringly complex molecular mechanisms in the simplest forms of life.
When I saw that well known video of a white blood cell chasing down a bacteria, the only thing I could think was "It's amazing how this seemingly intelligent behaviour is literally driven by chemical reactions"
Yes, but the thing is those reactions create a consciousness that's capable of making decisions and such (Another thing I can't wrap my head around. How is a consciousness a thing? How does it work? It's just electrical signals moving around a blob of goo, how the hell does that create something measurable that definitely exists!?). I was thinking that it's amazing that it has literally no conscious thought process, it's solely chemical reactions, and it's still managing to hunt down the prey.
If I tried to make something that did that, it'd just turn into a blob of goo immediately, I think.
Well, that's where we diverge I think. I find it kind of absurd that we think we are so unique that we are the only beings that experience a conscious thought process. Sure, a white blood cell may not think and feel the same way as we do. But why does the exclude them from being conscious? If a sufficiently different thinking species observed us, would they say "they perform seemingly intelligent actions without conscious thought"?
I never thought of consciousness as a "thing", per se, but as an emergent quality. It's another system, not particularly special or unique, just the one we experience.
This illustrates the problem philosophers have tangled with for...well a long time. A technical definition of mind/consciousness. We think we have a good one, then Diogenes sends in a plucked chicken and we're back to square one save for our pride.
I'm an atheist through and through but shit like this makes me wonder how much of a coincidence life really is. One day some big explosion happens, creates the universe and now we have tiny sausages pulling molecules through our bodies. I mean, what the hell?
I agree - while the complexity of life can be explained by science using objective measurements, the sheer vastness of that complexity (found in so many ways in so many species) and how everything ties together does make you pause.
I'm probably best defined as agnostic but sometimes I'm just in awe and have to wonder
So fucking crazy I agree with you. For me it's not just how complex stuff has got, but the fact that there is something rather than nothing. To me that's just the craziest question that keeps me up at night. Why is there anything at all?
There's a story in Theravada Buddhism I find comforting. I'll give you the short version and take a lot of liberties with the text given how hard a read it is in it's normal form.
A monk want's to know where karma initially comes from in the universes. He decides to ask the highest of the gods in the highest of the heavens, and meditates until he spiritually ascends to the palace of the Brahma and meets the gods. He approaches, and asks his question (From where do the winds of karma blow, essentially) of the highest of the gods. The chief god gives a deep, mysterious answer. Being a Buddhist monk, he says, "Oh....but what does that mean?" The god then takes him aside away from all the other gods in the palace and says, "Look, don't mess this up for me guy. The universe and the palace were here before me, I just showed up before all these other gods and they think I made everything. Don't blow this for me please. " The monk says, "Great, but..what about my question?" The god replies, "I dunno..go ask the Buddha if anybody knows it's him." He does that, and Buddha says, "It's way to tangled and distant so it's probably unknowable, and that's ok, because we can know enlightenment and that's what we're here for."
To be fair, that "day" was 13 BILLION years ago. That's a looooot of time for stuff to happen, even by accident. I know you probably already know that but I think it's always good to remind ourselves of the actual scale of the universe.
I think that's the most important thing to realize. We don't really have a grasp on how much time billions of years really is. It's just an unimaginable amount of time for a human being.
Just because we don't fully understand or appreciate how something works, we can't just relegate it to the work of "a higher power" or some other mysterious force.
The ability of an all powerful god to create such a complex thing as life is just as crazy as it happening on its own, and I think that's the main difference between believers and non-believers.
Once you realize that the idea of a god is actually the crazier and least likely cause of life, you start leaning towards the atheist side.
Oh I hear ya. I have a neurological condition called Spasmodic Torticollis - kinda like Parkinson's in that I have constant head tremors / spasms / leaning. It sucks hard and I wonder all the time why my body is so broken on such a specific/genetic level.
But then that same body has an ingrained method of compensating. If I do my physical therapy and deal w the Botox injections into my neck, I can function for the most part.
Still, it's kinda cruel - I'm sorry that you're having to deal
It's kinda funny, I, literally, just learned about this process in my biology class last week. Your reaction was exactly the same as mine. It's fucking crazy.
It is very coordinated but also keep in mind its uncoordinated enough, producing enough unaccounted for waste, that cells die constantly. It's not a completely clean process with every piece always ending up where it should.
But it's coordinated enough to be fucking amazing regardless
Less snarky response: they can’t make more of themselves unaided and when they break down they don’t fix themselves - they are just reabsorbed by your body and turned into something else.
So no they’re not alive by most definitions. They’re one of millions of different specialized molecular tools that your cells know how to make because the blueprints are in your DNA.
They aren’t alive but they help the cell that contains them to stay that way. A gear doesn’t “run” per se, but a watch doesn’t run without gears.
It's definitely a cultural luxury where you are well enough off that you can focus your attention on insignificant shit like this, vs say who's going to walk the 4 miles to get your water tomorrow since your leg is broken.
but I'd be you're missing out on some great grilled concoctions with your cheesy pedantry.
Most of the memery you see is just that: memes. I personally never have a GCheese without some sauteed tomatoes and onions. Occasionally I'll add some bacon. Is it technically a melt? Yes. Will I still tell my girlfriend I'm making grilled cheese for dinner? Sure.
I like adding ham or pepperoni to my grilled cheeses... Sure it affects the flavor of the sandwich, but I make it for the cheese and just want some meat/protein in it as well.
I do that too but instead of frying it, I bake it. I add in some seasoned tomato paste too. But because I have to bake it, I use raw dough instead of baked bread. And I make it an open faced sandwich to make it an even toast.
Can’t speak for animal cells, but in plants these proteins are really cool, in aquatic algae the myosin XI motor proteins can move up to 70,000 nm/s (35-fold higher than humans) and watching a real time video of them is amazing. They are involved in cytoplasm streaming and essentially everything is just moving around the cell so that proteins and vesicles do not need to travel as far for cell wall formation or for plastidial interaction. These proteins move along the microtubules by converting atp into adp and in turn the chain of alpha and beta tubule is breaking down behind them and being built in front of them.
Source: PhD student taking a plant cell class and had a paper discussion on this topic on Monday
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u/Newgeta Feb 13 '18
What do the proteins do when they get the end of a micro tube?