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1500 questions
45
votes
6 answers
Why are amino acids in biology homochiral?
Why are nearly all amino acids in organisms left-handed (exception is glycine which has no isomer) when abiotic samples typical have an even mix of left- and right-handed molecules?
Poshpaws
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45
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4 answers
Why do eukaryotic organisms have introns in their DNA?
We touched on introns and exons in my bio class, but unfortunately we didn't really talk about why Eukaryotes have introns. It would seem they would have to have some purpose since prokaryotes do not have them and they evolved first chronologically,…
Gordon Gustafson
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45
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2 answers
How do cockroaches resist the effects of ionizing radiation?
Cockroaches are very hardy insects. It is known that, among other things, they are able to withstand bursts of ionizing radiation that would kill a human being.
The explanations of this observed resistance I've seen include cell division not being…
user132
44
votes
4 answers
Is there any advantage to one blood type over another?
All humans can be grouped into ABO and Rh+/- blood groups (at a minimum). Is there any advantage at all to one group or the other? This article hints that there are some pathogens that display a preference to a blood type (for example…
Rory M
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44
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4 answers
Why are bruises not lethal?
Given the following:
bruises are caused by minor trauma which breaks blood vessels beneath the skin, causing bleeding
the mechanism by which bleeding stops is clotting
blood clots inside the body have an unfortunate tendency to get into the…
Mason Wheeler
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43
votes
6 answers
How do scientists kill the bacteria they themselves made resistant?
I was reading this article on researching bacteria resistance to silver by removing some of their genes.
Researchers then used "colony-scoring" software to measure the differences in growth and size of each plate's bacterial colony. E. coli strains…
WhatHiFi
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43
votes
3 answers
If the brain has no pain receptors, how come you can get a headache?
I've read many years ago in books, that the brain has no nerves on it, and if someone was touching your brain, you couldn't feel a thing.
Just two days before now, I had a very bad migraine, due to a cold. It's become better now, but when I had it I…
Zerium
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43
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3 answers
Why draw blood from veins rather than arteries?
Why draw blood from veins rather than arteries? Is it more convenient or safer?
ZZZ
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43
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2 answers
Can brain cells move?
I was discussing this with my brother. I'm pretty sure I read somewhere that they can move.
Thanks
EDIT: By movement I mean long distance migration (preferably within the brain only).
DLV
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43
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4 answers
Do plants produce any heat?
Many plants (e.g. roses, palms) can be protected from frost during the winter if shielded with an appropriate coat that can be bought in garden shops. Do plants produce any heat that can be kept inside with these "clothes"?
jabal
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43
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2 answers
Why don't we develop immunity against common cold?
We all suffer from common cold, and that, frequently. Why have we not developed immunity against it till now? By immunity I mean immunity as a species.
kinshukkashyap
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42
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3 answers
Why does vaccine development take so long?
The main principle behind a vaccine is to take a deactivated virus, "show" it to the immune system so it can "learn" how it looks like, so if and when the real virus does attack us, our immune system is already prepared for it. Vaccines have been…
vsz
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42
votes
5 answers
Why is cold water more refreshing than warm water?
Obviously, the temperature of water does not affect its chemical composition. At least not in the ranges we are likely to drink it in. Yet it is clearly far more pleasant and refreshing to drink cool water than it is to drink tepid or warm water.
Is…
terdon
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42
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6 answers
If evolution is not about increased complexity, why does so much complexity evolve?
In my last question I asked why we don't see increased complexity in artificial life simulations of evolution. It seems I had fallen for a common misconception, that evolution was about improvement by increasing complexity. One comment discussing…
vonjd
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42
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4 answers
Why would a plant evolve to produce an addictive chemical?
It seems kind of anti-productive in terms of survival for a plant to produce an addictive chemical as that plant will constantly be sought after by animals that ingest it. In this instance, I'm looking for a possible general & inclusive answer here…
rhill45
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