
Life's clockwork: Scientist shows how molecular engines keep us ticking - lelf
https://phys.org/news/2020-01-life-clockwork-scientist-molecular.html
======
Merrill
Adenosine triphosphate (ATP) is fascinating stuff. Your body makes roughly its
own weight of ATP daily.

~~~
Pinegulf
Really? I'd love to read more. Could you point to source? Edit: ATP is about
0.5kg/mol. So 80kg person would be 160 moles of ATP. Hmm.

~~~
Merrill
>Other processes regenerate ATP so that the human body recycles its own body
weight equivalent in ATP each day.

[https://en.wikipedia.org/wiki/Adenosine_triphosphate](https://en.wikipedia.org/wiki/Adenosine_triphosphate)

When ATP is used to power a biological process, it is converted to the
diphosphate or monophosphate. Metabolic processes, such as glycolysis, then
regenerate the triphosphate.

[https://en.wikipedia.org/wiki/Adenosine_triphosphate#ATP_rec...](https://en.wikipedia.org/wiki/Adenosine_triphosphate#ATP_recycling)

~~~
tremon
I wouldn't classify that as "makes", though. The basic structure (AxP) remains
roughly the same, only the energy transport (phospate group) is ejected or
reassembled.

It's a bit like arguing that unloading containers from a cargo ship, and
reloading it with new cargo, is the same as building a new ship.

~~~
gibbonsrcool
All definitions of the word "make" include phrases liking "combining parts"
and "putting together"

------
_Microft
"I made them work last night.

"Made _what_ work last night?

"The iterative machines!

"They worked before, what do you mean?

"No, not at this size. I re-designed the process and ran simulations until I
had a new starting point. I replicated the first specimens and left them to
themselves. They work now. They collect matter, they process it, they
function! They REPLICATE! All it took was setting the penalty correctly.

"What scales of size are we talking about? What components did you use?

"Well, there _are no_ components in that sense anymore. The level of
integration is astounding! Everything that wasn't absolutely needed for
function was removed by the optimizer and that what remained was functionally
compressed and reuses as many existing 'components' as possible. That's what I
meant. It required a severe penalty for the introduction of new 'components'
and that is what did the trick. The results are self-selecting now. Specimen
with more suitable parameters for the environment are able to out-replicate
others and the succeeding ones were more likely to be based on successful,
i.e. faster replicating ones. They improve themselves! And the results were
_orders of magnitude_ smaller than anticipated! This out-replication seems to
have taken the role of selection. The things that work best will sometimes, by
chance, create modified copies that work even better. Their faster self-
replication makes them replace the old ensemble.

"That's prettty crazy.. How many orders of magnitude are we talking about?

"Haha.. see, the power source is a component that uses chemical compounds as
fuel and extracts power from them. These are one of the larger parts of the
machines and even then they are not even a micron across. A micron! And I
wouldn't really call the rest of the parts _components_ anymore. They _are
not_ clearly separated components anymore. The boundaries are fluid, a lot of
parts are reused for different purposes, it is more one thing than a machine
with different components. The whole things look like an _awful mess_! There
is little discernable structure, heck, they don't even have a rigid structure
anymore! The whole things can warp and move but they work. They work! They
react to the environment! They can move in direction of a chemical gradient
when they require the material for replication! We are talking about micro-
machines. Heck, most of their parts are on a molecular level.

"Are you serious? That's madness. They are basically undetectable at these
sizes. Have you any idea how dangerous this might be if they ever escaped your
lab? How do you turn them off? What if they started converting available
matter into copies of themselves?!

"Nah, they sure won't escape and if they do, the range of materials they can
consume is too limited. It would be of concern if they managed - which I admit
is a possibility because of their self-replication and the mixing of
procedural parameters that occurs in the process - to increase the variety of
input materials or worse, if they could harvest ambient energy in the form of
heat or light.

"What do you mean by mixing of procedural parameters...?

"Yes, that was unfortunately required and makes the whole process somewhat
unpredictable. Unfortunately - or maybe exactly fortunately? - I didn't get
very far with intentionally designing these things. Once I went down the path
of self-replication and introduced a way to not only self-replicate but
letting them mix their own procedural parameters with the ones from other
copies in the process, working results appeared really fast. I'm wondering if
that might be the next level of machines? Us being no longer being assembled
from components that were created in a plant and being loaded with a program
but working machines from almost nothing! Starting out small, increasing
themselves in mass and complexity until they reach a working condition. They
are basically plants themselves.

"Spare me. How do you pause the process?

"Welll, that's sort of an issue so far. Since there are no separate components
anymore, you can't really switch off the power. You can physically destroy
them though or introduce substances that interfere with the machinery to
disrupt the processes enough so that they permanently stop working. Or you
withdraw the building materials but since they are such minuscule machines,
they require very little and will work for quite a while. They deteriorate on
their own with time if that's a relief. I do not know yet why this happens but
after a while the processes slow down and most of the machines stop working
shortly after that. On the other hand, they are frequently being replaced by
succeeding generations which are usually more capable than earlier. It's
definitely something we need to look out for.

\------

Yes, it's totally off-topic but a short story I started a while ago. It is
about a robo-engineer experimenting with microscopic machines and thereby
creating what we call life.

~~~
nkrisc
Thanks for sharing, off-topic or not, I really enjoyed it.

> Us being no longer being assembled from components that were created in a
> plant and being loaded with a program but working machines from almost
> nothing!

This sentence needs some love, though. Had to read it a few times.

~~~
_Microft
I'll rework that, thanks for the feedback! I'm not an native english speaker
and we Germans are prone to convoluted sentences ;)

~~~
nkrisc
I'm not going to try diagramming that sentence, but I wouldn't be surprised if
it was grammatically correct English nonetheless.

