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1500 questions
26
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3 answers
Does any molecule other than DNA have a double-helical structure?
DNA is known to have a double-helical structure. Do any other molecules have this structure?
The Riddler
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Why do people have antibodies against other blood types?
The ABO blood type divides each blood type according to whether they have the "A" and "B" antigen(s) (AB has both, O has none). People also have antibodies against the antigens they don't have (AB has none, O has both), even before they have ever…
dtech
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26
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Do all proteins start with methionine?
Start codon AUG also codes for methionine and without start codon translation does not happen. And even the ambiguous codon GUG codes for methionine when it is first. So does this mean that all proteins start with methionine as the first amino acid.
sreekara
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26
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Why do mints make your mouth feel cold?
Why do mints make your mouth feel cold? And specifically, why does your mouth feel so cold if you eat a few mints and then drink a glass of cold water afterwards?
rotaredom
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26
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What's the mechanism for being mentally tired?
I notice that after long tests, or long periods of critical thinking, my body and mind feel noticeably tired. Why does this happen? Are the neurons in my head not firing as quickly, or is there just a perceived lack of mental concentration?
What…
Dupontrocks11
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5 answers
Why is a heritability coefficient not an index of how "genetic" something is?
On his blog, Eric Turkheimer writes:
[T]aken as a number, a unit of analysis, heritability coefficients are
funny things to aggregate on such a massive level. What exactly are
we supposed to make of the fact that twins studies in the
…
user1205901 - Слава Україні
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26
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1 answer
Why do you die if you cannot breathe?
I was wondering what the actual reason for death by suffocation is. Obviously it is related to oxygen deprivation. But what is the underlying cause of death?
Is it due to insufficient oxygen for aerobic respiration, and the resulting lack of ATP…
Meep
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26
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1 answer
Why does hair grow after trimming but remains at a constant length after a while?
Some hair especially body hair regrows after trimming but stops growing after a while. What is the mechanism behind control of hair growth and how is the length limit determined?
Mohini Yadav
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26
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3 answers
Why deoxyribose for DNA and ribose for RNA?
Why is DNA made out of deoxyribose and RNA made of ribose? Why can't they both use ribose or deoxyribose? I think that the deoxyribose gives an advantage in storing genes, the job of DNA and ribose is better dealt with outside the nucleus...but why?
TanMath
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What are the side-effects of long-term liquid breathing?
I just saw a recent Physics question that mentioned liquid breathing (which I had never heard of before) and I started to wonder about its long-term effects. Let's imagine a person underwent liquid breathing for some wacky reason - see the Wikipedia…
HDE 226868
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26
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2 answers
How is duration of efficacy estimated for vaccines?
Vaccines, especially those given in adulthood, usually have term limits attached, eg: 10 years for yellow fever or 3 years for typhoid. Since presumably the time course of an immune response is no great respecter of our calendrical conventions, and…
walkytalky
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3 answers
What limits our healing speed?
Our bodies can repair quite a number of injuries very well. However, it takes time. For larger wounds, complete recovery can last many weeks. Why is this time so long, what is the most important limiting factor? The speed of cell division? I thought…
vsz
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26
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Why do stars disappear when I look at them?
I've noticed that when I'm out at night stars seem to vanish when I focus on them. I assume the reason is physiological and not astronomic. Why does this happen? I would expect that things would be more clear when I focus on them.
Shep
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26
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4 answers
How many genes do we share with our mother?
Somewhere I have read we share more than 99% of our genes with every other other person and 98% of our genes with chimpanzees. What does this mean? Don't we share 50% of our genes with our mother and 50% with our father?
I've found an another…
cpx
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Are humans the only animal that requires "clean water"?
I've seen a number of animals - dogs, cats, squirrels, ducks and geese, etc drink from puddles, some of them were muddy, others had green flora growing under water. Same goes for lakes and rivers. A human would not drink that. Do animals experience…
Alex Stone
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