The blank spots

[nancylebov]

They’re called “vaults”. They‘re in our cells, and in those of every plant, animal, and fungus. Like ribosomes, they’re atomically precise self-assembled structures made of protein and RNA, but they’re big and hollow, large enough to pack many ribosomes inside. They’re relatively simple and symmetric: A vault consists of two identical halves, each consisting almost entirely of 39 identical copies of a single, large protein (see figure). The vault structure was recently determined to near-atomic resolution, revealing enough detail to show how the proteins fold and fit together. Looking forward, this information could help protein engineers develop methodologies for designing large self-assembling structures.

Vaults are unusual in many ways, but what I find most surprising about them is this:

To this day, no one knows what they do.

No one knows what sleep is for, either, though at least part of its function seems to have something to do with memory.

What are some other notable blank spots?

Link thanks to shadesong.

Comments

[tamnonlinear.livejournal.com]

When people have been deprived of sleep for long periods of time, they also lose the ability to regulate their metabolism. Body core temperature starts dropping, and is thought to be the eventual cause of death in the few documented cases of death by lack of sleep. Interestingly, dreaming (REM sleep) is most common in mammals and birds, warm-blooded creatures, and rarer in cold blooded creatures that may sleep but don't seem to undergo REM cycles.

[siderea]

Why does the brain have opioid receptors? Was it just a terrible coincidence that opioids are found in plants/food?

Why do humans (and other mammals) get drunk upon consuming ethanol? Was our highly-specific alcohol-metabolizing system the best evolution could come up with? Because ethanol is a natural product of rot in food, and thus a high-likelihood hazzard -- becoming intoxicated by it does not seem like an evolutionary advantage.

Schizophrenia. Depression.

Why do we have personalities?

Of course: music and dance, but then I've spoken of my thoughts on that recently. :)

Why don't female humans have estrus?

[holzman.livejournal.com]

becoming intoxicated by it does not seem like an evolutionary advantage.

It doesn't have to be. It just has to fail to be more disadvantageous than other reactions to ethanol, which might be why ethanol doesn't kill us on contact.

[ckd]

Knowledge is fractal: the more you know, the more you find out that you don't know.

[autopope.livejournal.com]

Okay, you've just officially blown my mind.

(Vaults weren't discovered until around the time I graduated -- and stopped tracking discoveries in cell biology -- and they haven't surfaced in the glossy science news mags like NS or SciAm. And they're just plain freaky. Something that big has got to do something important, otherwise a single nucleotide mutation would put paid to them pretty quickly.)

[communicator.livejournal.com]

Brilliant information

[dcseain.livejournal.com]

How cool is that! It's amazing the advances since my days in molecular biology/genetics. :D

[litch.livejournal.com]

Why do we have personalities?

Dennet's take on this in Consciousness Explained (http://en.wikipedia.org/wiki/Consciousness_Explained) is one of the better approaches to an explanation I have encountered

some other questions:
how is memory encoded

I think what initiates cell devision is still pretty murky, but there have been a lot of advances in cell cycle knowledge in the last decade that may be closer to addressing that.

[avram]

According to Wikipedia, Drexler is exaggerating. First, not every species has vaults in its cells. (One that doesn't: Drosophila melanogaster, the fruit fly used in so many biology experiments.) Second, while vaults aren't fully understood, there does seem to have been some fruitful research done into their function.

Also, that link is broken. Knock the space off the end of it.

[marykaykare.livejournal.com]

We know amazingly little about the brain: how it works, why it goes wrong and how to fix it when it does. I suspect the brain of not wanting us to know just how much of 'us' is electrical/chemical.

MKK

[sterlingspider.livejournal.com]

Beat me to it :)

Notably: the actual mechanism of death is thought to be immunological. The lowered core temperature leaves us exposed to infections that we are nearly constantly exposed to, yet a person with a normal temperature range would never have to worry about. This was apparently the main source of confusion about these deaths as no one could find anything weird going on in these people's bodies (other then the whole... death... thing).

Another interesting sleep fact: when systematically deprived of REM sleep we do not bother to make up much of it in subsequent (uninterrupted) sleep cycles, yet when deprived of slow wave sleep (the super deep, near-catatonia sleep) we make it up to the minute, almost to the exclusion of the other stages of sleep in the sleep cycles immediately subsequent to the deprivation.

[demonspawnmom.livejournal.com]

Error 404 - I'll give the links another try later.

[(Anonymous)]

In general, we don't know lower bounds on how much work problems take to solve. That is, we have some known solutions, but as far as I know, there just aren't any results that say "this problem cannot be solved in less than K steps." (I suppose you could come up with problems that can be solved in one step to contradict this, but you get the idea here.)

We do have reduction proofs, showing that solving one problem lets you solve others. We even have the set of NP-complete problems, where a polynomial-time algorithm for any of those problems can be used to construct a polynomial-time algorithm for any other problem. But we don't actually know that any of those problems are hard. There's nothing stopping someone from showing up tomorrow with a polynomial-time algorithm for the knapsack problem or traveling salesman or whatever, and just knocking all our assumed hardness-of-problems ideas over at once.


--albatross