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Physicists Find Clue as To Why the DNA Double Helix Twists To the Right
New submitter Annanag writes Most organic molecules have left- or right-handed versions, mirror images of each other, just like gloves. For some reason, life always seems to favor one version over the other — the DNA double helix in its standard form always twists like a right-handed screw, for example. But why this preference for left or right happens has always been a mystery. Now, in an experiment that took 13 years to perfect, physicists have found hints that this asymmetry of life could have been caused by electrons from nuclear decay in the early days of evolution.
Nowadays it seems like almost everything is twisting to the right...
#DeleteChrome
Nope. A helix has an intrinsic twist direction invariant from the point of view.
Check it yourself. Get two identical springs and put them side by side, flip one and voila you have the same configuration than before.
Depending on how you define "life", yes. In fact, almost certainly, regardless of which definition of "life" you choose. Selection can occur in any kind of chemical or physical process in which produces similar but not always identical results. There's nothing special about the particular chemical processes we call "life", nor some magic line in the sand you can draw and say "this is life, and this isn't" -- it gets rather fuzzy on the edges, and the distinction between life and other chemical processes is as arbitrary as the distinction between which celestial bodies we decide to call "planets" and which we decide don't qualify. Nature doesn't care much for our arbitrary distinctions.
"Convictions are more dangerous enemies of truth than lies."
http://en.wikipedia.org/wiki/T...
If there's anything I learned from Star Trek TOS, is that no matter what planet you land on, you can always hook up with the local humanoid females.
Oh yeah? We'll soon see about -
Hmm. Maybe one of these is broken. I'm getting more springs.
systemd is Roko's Basilisk.
If it bent to the left, that'd be a bit...sinister.
Chas - The one, the only.
THANK GOD!!!
Article:
The interaction of left-handed electrons with organic molecules is not the only potential explanation for the chiral asymmetry of life.. Meierhenrich favours an alternative â" the circularly polarized light that is produced by the scattering of light in the atmosphere and in neutron stars3. In 2011, Meierhenrich and colleages showed4 that such light could transfer its handedness to amino acids.
But even demonstrating how a common physical phenomenon would have favoured left-handed amino acids over right-handed ones would not tell us that this was how life evolved, adds Laurence Barron, a chemist at the University of Glasgow, UK. âoeThere are no clinchers. We may never know.â
The new work is interesting and important, but its primary significance is that it makes future work distinguishing the possible alternatives more challenging. It's also interesting because unlike the other two proposed mechanisms it is a result of the fundamental asymmetry in the weak force rather than an accidental boundary condition, so it implies that life everywhere is more likely than not to be right-handed, whereas the explanations involving magnetic fields will make a universe that's 50/50 right/left.
Blasphemy is a human right. Blasphemophobia kills.