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I should have loved biology

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Re: I should have loved biology

#151

Post by ta988 »

adrian_b wrote: post #120
Pulcinella wrote: post #36

Earlier quoted context omitted.

Yeah see the art of David Goodsell. I believe he said the concentrations of the various biomolecules are roughly accurate based on calculations he does before starting painting. Cells are incredibly crowded. The human body being 60-70% water is usually presented in pop-sci as “wow we are mostly water!” but that’s actually very concentrated for chemical reactions. You usually don’t perform reactions that concentrated…

All the living cells spend continuously a lot of energy as long as they are still alive for avoiding the appearance of precipitates inside the cell, e.g. by pumping out of the cells the ions of calcium and sodium and pumping inside the cell the ions of magnesium and potassium, because the former are much more prone to produce precipitates than the latter. This continuous ion pumping is a major component of the energy…

It is a big part of the communication, regulation and sensory system of cells. A lot of receptors are linked to ion channels for example. That's also the reason why there are pumps to bring the ions back on the other side too.

Re: I should have loved biology

#152

Post by [deleted] »

oldsecondhand wrote: post #102
Pulcinella wrote: post #36

Earlier quoted context omitted.

Yeah see the art of David Goodsell. I believe he said the concentrations of the various biomolecules are roughly accurate based on calculations he does before starting painting. Cells are incredibly crowded. The human body being 60-70% water is usually presented in pop-sci as “wow we are mostly water!” but that’s actually very concentrated for chemical reactions. You usually don’t perform reactions that concentrated…

> It’s a wonder all this stuff doesn’t just gunk up It does gunk up but it takes a few decades.

[deleted]

Re: I should have loved biology

#153

Post by Daniel_sk »

Modern biology is maybe able to fully disassemble the simplest living forms - but assembling these microstructures synthetically is still way beyond what our tools can do. It’s same like a microchip where a whole chain of small steps lead to factories and these produced the chips. And we don’t know how the original cell/life factories looked like, we just have the cells that are now self-assembling (they are now both the highly complex factory and the product). We can take a cell and modify the code, but it’s hard to do it from scratch because you would need to skip bilions of steps that lead to these microstructures.

I have been recently thinking what is actually life - could it be a manifestation of a fundamental physical law? And this article had an interesting take: https://www.pnas.org/doi/10.1073/pnas.1620001114 “How nonequilibrium thermodynamics speaks to the mystery of life”

Re: I should have loved biology

#154

Post by Koshkin »

Infinitesimus wrote: post #131
dataflow wrote: post #104

Earlier quoted context omitted.

Except it seems like a way harder question!

... it'll be fun if you start from what happens when the enter key is pressed- the mechanics and electronics involved in submitting that URL (and some chemistry and physics behind what your eyes see on the screen), the physical transmission of the signal from your computer to through the interwebs and some error correction protocols to ensure your signals are still useful. Maybe toss a line or two in about the comple…

> it'll be fun

Not during an interview, though. The interviewer would see it as trolling (at best), and you would fail the interview. And for a good reason! Because as an engineer (and an intelligent person in general) you must be able to separate what is essential from the non-essential for the subject in question. For instance, the physics or the physiology of the process of pushing a key on a keyboard is probably not what the question was about, nor do those things in fact have much to do with typing, even (which you can do on a touchscreen or using the mouse).

Re: I should have loved biology

#155

Post by AinderS »

azalemeth wrote: post #115
tambourine_man wrote: post #111

Earlier quoted context omitted.

> They are structurally like a cathedral built by a blind and deranged architect That's one of the best things I read all week.

The other word missing is "cheap". Proteins are under a massive selection pressure: many thermodynamic reactions in fundamental bits of biology are as thermodynamically efficient as they can be, else some slightly more efficient mutant would have out-competed it aeons ago. I became interested in biology as a physicist when I realised that all of the problems, on some level, boil down to putting a load of lego pieces…

> It's why I work at the intersection of the two fields.

Sounds fascinating. May I ask which field that is/what type of work you do?

Re: I should have loved biology

#156

Post by charlie0 »

randcraw wrote: post #126
MereInterest wrote: post #118

Earlier quoted context omitted.

There was a paper a few years ago about a similar effect in artificial neural networks [0]. The gist was that a large network can contain many subnetworks, and the number of subnetworks grows much faster than the size of the network they are contained in. They were able to find a subnetwork in a randomly weighted network with equivalent performance to a trained network of a much smaller size. [0] https://arxiv.org/ab…

Nice. Sounds like these self-assembling subnets could be the basis for a viable model explaining the mechanisms behind early evolution.

Skynet?

Re: I should have loved biology

#157

Post by conradev »

Daniel_sk wrote: post #153

Modern biology is maybe able to fully disassemble the simplest living forms - but assembling these microstructures synthetically is still way beyond what our tools can do. It’s same like a microchip where a whole chain of small steps lead to factories and these produced the chips. And we don’t know how the original cell/life factories looked like, we just have the cells that are now self-assembling (they are now both…

I enjoyed this paper on the relationship between entropy and life – lots of overlap with that article:

"Life and its evolution are time-oriented, irreversible phenomena that have produced a steady increase in complexity over billions of years. The second law of thermodynamics is the only fundamental law in physics that distinguishes the past from the future and so this law, and its statistical underpinning, offer the only physical principle that can govern any macroscopic irreversible phenomenon, including life."

https://www.mdpi.com/1099-4300/21/12/1211/htm

Re: I should have loved biology

#159

Post by _dain_ »

feet wrote: post #142
Balgair wrote: post #109

Earlier quoted context omitted.

The two questions I really remember from my neuroscience grad program are: "You discover a mouse that can sense radiation. How does it do it?" "You are riding a bicycle. Explain." We had to do it in 2 pages, NSF grant rules on spacing and margins.

>You are riding a bicycle. Explain Oh man, where do I even start? Sensory input from the inner ear to balance, the networks that handle feedback from afferent signals from the periphery, efferent pathways to control motor movement. I don't even know all the details but it's mind bogglingly complex. Do I explain the molecular basis of action potentials? The modulating effects of inhibitory feedback within the networks…

Or the physics of the bicycle itself! It can stay up even without a rider.
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