Posted on 11/16/2005 3:40:35 AM PST by snarks_when_bored
* 14:02 15 November 2005
* NewScientist.com news service
* Gaia Vince
A new microscope sensitive enough to track the real-time motion of a single protein, right down to the scale of its individual atoms, has revealed how genes are copied from DNA – a process essential to life.
The novel device allows users to achieve the highest-resolution measurements ever, equivalent to the diameter of a single hydrogen atom, says Steven Block, who designed it with colleagues at Stanford University in California.
Block was able to use the microscope to track a molecule of DNA from an E.coli bacterium, settling a long-standing scientific debate about the precise method in which genetic material is copied for use.
The molecular double-helix of DNA resembles a twisted ladder consisting of two strands connected by “rungs” called bases. The bases, which are known by the abbreviations A, T, G and C, encode genetic information, and the sequence in which they appear “spell out” different genes.
Every time a new protein is made, the genetic information for that protein must first be transcribed from its DNA blueprint. The transcriber, an enzyme called RNA polymerase (RNAP), latches on to the DNA ladder and pulls a small section apart lengthwise. As it works its way down the section of DNA, RNAP copies the sequence of bases and builds a complementary strand of RNA – the first step in a new protein.
“For years, people have known that RNA is made up one base at a time,” Block says. “But that has left open the question of whether the RNAP enzyme actually climbs up the DNA ladder one rung at a time, or does it move instead in chunks – for example, does it add three bases, then jump along and add another three bases.
Light and helium
In order to settle the question, the researchers designed equipment that was able to very accurately monitor the movements of a single DNA molecule.
Block chemically bonded one end of the DNA length to a glass bead. The bead was just 1 micrometre across, a thousand times the length of the DNA molecule and, crucially, a billion times its volume. He then bonded the RNAP enzyme to another bead. Both beads were placed in a watery substrate on a microscope slide.
Using mirrors, he then focused two infrared laser beams down onto each bead. Because the glass bead was in water, there was a refractive (optical density) difference between the glass and water, which caused the laser to bend and focus the light so that Block knew exactly where each bead was.
But in dealing with such small objects, he could not afford any of the normal wobbles in the light that occur when the photons have to pass through different densities of air at differing temperatures. So, he encased the whole microscope in a box containing helium. Helium has a very low refractive index so, even if temperature fluctuations occurred, the effect would be too small to matter.
One by one
The group then manipulated one of the glass beads until the RNAP latched on to a rung on the DNA molecule. As the enzyme moved along the bases, it tugged the glass bead it was bonded too, moving the two beads toward each together. The RNAP jerked along the DNA, pausing between jerks to churn out RNA transcribed bases. It was by precisely measuring the lengths of the jerks that Block determined how many bases it transcribed each time.
“The RNAP climbs the DNA ladder one base pair at a time – that is probably the right answer,” he says.
“It’s a very neat system – amazing to be able see molecular details and work out how DNA is transcribed for the first time,” said Justin Molloy, who has pioneered similar work at the National Institute for Medical Research, London. “It’s pretty incredible. You would never have believed it could be possible 10 years ago.”
Journal reference: Nature (DOI: 10.1038/nature04268)
And in the experiment glued a glass bead on one end of the strands in effect adding an unnatural load the "unbonding" had to drag from one end and you have in effect altered the normal condition (maybe it unzips from both end to the middle normally)
Bottom line it's no more amazing for mechanical bonds to upzip one bond at a time then a zipper to unzip one tooth at a time... all you need in a little force to start the unzipping (say a chemical reaction creating a electrify charge?)
IIRC it was Jane Curtin. ;-)
Cheers!
Zarqawi attempts to impose the death sentence himself, rather than waiting for the afterlife; no "cross" (and for that matter, no Father-Son-Holy Spirit) in Islam; Islam was founded by a militaristic pedophile; and other differences too numerous to mention.
Your theology is as insound as Fester's science.
Cheers, you lovable apostate, you! ;-)
Well, they both tend to overcharge;
and neither one likes to be exposed;
and they hate laywers (...who doesn't ?)
Full Disclosure:
Ooh-eee-ooh-ah-ah, ting-tang, walla-walla-bing-bang,
ooh-eee-ooh-ah-ah, ting-tang-walla-walla bang bang!
BZZZZZT!!! Go sit in the corner.
Automobiles are not organic, are not alive, and have no ability to reproduce. Makes it kinda hard to evolve, now, doesn't it?
Full Disclosure: Paraphrase from Science Made Stupid: "Early mammals generally bore their young alive which was a great advantage. As research has conclusively shown, animals that bore their young dead generally got nowhere."
Cheers!
You're right! She and Dan were great weren't they?
¡Feliz Navidad!
You never answered my question; What is wrong with interracial relationships?
Also, who forced you to remove that quote from your homepage? It wasn't us.
My quibble was with your words "The ONLY reason...".
I had assumed you had got caught up in the heat of the argument and overstated your case.
Since automobiles aren't alive, they can't evolve; and they are far too large, complex, and useful that "a natural process" would be the first explanation that came to mind--I would take such machinery to be a sign of either a) civilization or b) non-union machinists :-)
" Full Disclosure: Paraphrase from Science Made Stupid:..."
Now, you're generally harmless, but are you in competition with Elsie for most meaningless posts?
Science Made Stupid is an side-splittingly funny, juvenile, and tasteless paperback purporting to instruct the layperson about science, and getting it all wrong. Think Dave Barry crossed with Science for Dummies. The reference was merely to underscore the point that automobiles really aren't alive and so cannot have evolved to their present position.
As far as meaningless posts, I have taken it upon myself to liberally populate these threads with bad puns, in order to provide a change of pace from some of the flame wars.
Cheers!
By and large it appears you know where I'm coming from. Yes, I make a "huge" assumption, namely that every particle of matter is, and should prove to be, evidence of intelligent design.
Just use a standard definiton of intelligence. I'm not into semantic games. If there is a scientific means of ascertaining the presence of intelligence, what is it?
It is my contention that, if there are any phenomena human reason is able to comprehend, then it was intelligently designed. I do not have a set of hypotheses and tests to satisfy the purist, but I certainly am not about to throw in the towel as if the possibility is totally beyond the realm of scientific endeavor.
Yes indeed. I read words more carefully than you blow them out uranus.
Sorry, didn't want to embarrass you with the words you have described as giving a glimpse of your ideology.
"I had just posted today trying to start a small, but concise, homepage, to let everyone know a little about me and my ideology, beliefs etc" If the quote wasn't what you believed, why did you post it on your homepage? It's not like it's that ambiguous; it's an open criticism of race-mixing. How could you NOT know what it was saying? You say, "Since I did not fully agreed with the quote, I decided to remove it." That makes no sense. It's a very small quote with only one point, that race-mixing is destroying the *culture*. It seems pretty far-fetched that you would put such a clear-meaning quote on your homepage, a page you said you were building "...to let everyone know a little about me and my ideology, beliefs etc." if you didn't agree with it. If you don't believe in race-mixing, why not just say it? Are you scared to stand for what you believe in?
"You're trying arent you all? You think you can stifle me by digressing from the topic, don't you?"
I actually asked you other questions in my previous posts too, which you have also not answered. I still have not received an answer about your odd theory of divine emotional inferences. I asked if I had an emotional inference that it was ok to kill babies, was that from God? You said previously that, "Whatever emotional inferences I make, or anyone else makes for that matter, emanate from the Supreme One - God." The right or wrong of killing babies should make no difference in whether the emotional inference came from God, since you said, " Whatever emotional inferences I make..."; there was no differentiation between good or evil ones.
"It's not as if you were born to live like a brute and ignoramus - you were born to follow virtue and knowledge."
Courage to say what you believe is also a virtue.
"Let not fear rule your lives."
Pretty funny coming from someone ashamed of his own beliefs and too scared to discuss them publicly.
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