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)
I'm not being coy. What you do is design -- intelligent design. You are a living, breathing example of the fact that supernatural actions and agents are neither necessary nor sufficient to put forth an intelligent design hypothesis.
Just as there is need for you to claim that you "created everything," there is no reason to paste that claim onto the ID hypothesis.
Ill just continue to watch you dig deeper and deeper. It has been fun so far.
The bare facts are not what needs to be falsifiable it is the initial hypothesis (hypotheses) that need to be falsifiable. Without that ability, the theory will simply be a collection of hypotheses that may or may not be accurate. In other words it would be a collection of useless hypotheses.
Without the framework of a theory, the 'bare facts' are just random bits of information.
You and a good many others say so often and with a great deal of certitude, but I have no reason to believe this is truly the case. On what basis do you make this sweeping claim? Is this something you've taught yourself? Is it "intuitive?" For that matter is it a "falsifiable" claim?
You want the hands of science tied by a philosphy. Fine. But don't expect the rest of the world to follow suit.
Bare facts and "random bits of information" are not synonymous, but both can be scientific.
Hey, I'm not the one who's in a depression, am I?
"Coy" is exactly the right word. When you pin down any IDer he/she will eventually say the designer is God (Behe did under cross examination). You make "the biotech guy" do the same as God, they must therefore be as God.
So, by my Godness as defined by r9etb, I banish all IDers to the rug under the stairs where they are to remain until the Phorids and Ichneumons are finished. Then they will be removed to an entirely inappropriate rock stratum as fossils.
What a hoot!
Thanks for the ping. Very interesting. Especially that the RNA molecule moves up the DNA molecule with enough strength to pull the glass beads together. I wonder where that strength comes from, and whether the RNA molecule moves in ripples like an inch-worm.
Also, I wonder what happens if the free end of the RNA molecule encounters the middle of a DNA molecule. Does it start from the middle and replicate both ways, or does it first move to the end of the DNA molecule and start replicating from there?
If you had to live in this state with all these leftist nutjobs in chicago running the whole show you would have bouts of it too! ;)
I commented on the post I did cuz it sure looked to me like you were agreeing in a post you meant to make in opposition.
LOL!
Amazing. A "conservative" who elevates feelings to the level of facts.
I'm always amazed at how easily creationists take up Lib tactics. ID is the new PC - trying to re-define reality to conform to a political ideology.
The DNA dependent RNA polymerase starts at a unique place on one DNA strand and goes only in one direction.
I am sure reason has very little to do with what you believe or do not believe.
"On what basis do you make this sweeping claim?"
Because there is no evidence conceivable that could not be used to support the idea of a designer. What possible evidence would you accept as being against the idea of a designer? Is there even a hypothetical fact that could go against the idea of a designer? I know of none.
"Is this something you've taught yourself? Is it "intuitive?"
It's a logical necessity.
"You want the hands of science tied by a philosophy."
More than that, I want the hands of science to be constrained by reality; by EVIDENCE.
"Fine. But don't expect the rest of the world to follow suit."
I don't. Most of the world is perfectly content to follow whatever mystical mush that is thrown before them.
False. I'm not trying to force inscrutability. ID theory places no limits on the designer. "scrutability" is a limit. If you want the designer to be fathomable then you need to start saying what the designers motives are. If we don't know the designer's motives then of necessity the designer is inscrutable.
Please cite where Behe, et al., state that the designer "must be inscrutable."
Behe et al place no limits on the designer. They say nothing about the designer at all. The designer is a cipher, a blank, and therefore inscrutable. I can understand why you are desparate for this to be not so.
LOL
Would be great to see some DNA pictures as long as it wasn't mine. Don't want anyone seeing what's in my geans.
I reckon that places the reality ball firmly in my court, then. Why you feel so obligated to avoid reality is one of those mysteries that science will never solve.
You state"The 100 million corpses evokes the history of Communist China, Communist Russia, Communist Vietnam, Communist Cambodia, Communist North Korea.... All avowedly atheist. And they didn't really rely on modern technology to do it, either, except perhaps the use of firearms rather than swords.
There is a logic problem with this. It's called 'Joint Effect'
Are the deaths the direct result of atheism or the result of some other component of Communism, perhaps the demand within communism that class war is necessary?
Fester has been digging that particular hole for months now. He used to produce the standard anti-evolution canards but for some mysterious reason gave up on them, and now ploughs this singular lonely metaphysical furrow of, "everything is designed because I know that everything is designed and that is science."
I read. You should try it.
Science is continually discussing what can and cannot be studied productively. The list changes with available technology, but it will never include the supernatural. Except occasionally to demonstrate that a specific supernatural explanation is unproductive.
Yes, but it still doesn't explain a thing about the initial conditions and prior states of our universe, which lead up to the grand design we see today.
No. A conservative who understands the purpose and scope of science.
I'm always amazed at how easily creationists take up Lib tactics.
The lib tactics belong to people like you who would perpetrate fraud in the name of science, consistently misinterpret and misrepresent evidence, engage in ad-hominem ad nausaeum, all the while claiming to be intellectually superior.
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