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)
"The dictionary definition of design suits me fine. No need for science to give it a special meaning of its own."
Which one would that be?
(I note you have still refused to give a definition. I assume you don't know of one. If you can't even define design, how do you know it when you see it?)
Two V's or double U?
Now that is REALLY the question!
Whew!
Got to here and now it's only 753!
You are supernatural? Cool!
Just wait!!!
Proverbs 22:6
Train a child in the way he should go, and when he is old he will not turn from it.
I've replied to the Beast!
Could you please take a short segment of DNA that contains some coding, highly preserved non-coding, and non-preserved non-coding sequences and perform your statistical/mathematical analysis on each sequence showing your results. Failing this, show why you believe it to be true, beyond your feeling that it can be done, preferably with cites.
"Islam is a threat of man against man in the name of and by the direction of allah. "
Sharia law is presented as the will of Allah on earth. also the Koran contains many versus where Mohamed acts on behalf of Allah as an instrument of vengeance on man woman and child.
"Islam is a threat of man against man in the name of and by the direction of Allah. While Christians of today aren't perpetrating such a thing, I would offer that the christian bible shows a God to man aggression, threat, punishment for lack of compliance in the area of worship. "
Yes I agree the old testament is full of such references, however if you believe in the Christian message that Jesus came and fulfilled Mossaic law then, Christians as such live in a new relationship with god. That of love,grace forgiveness. These are not things that existed in the old testament relationship. it may seem like a small difference but for example contrast the works of Jesus such as befriending a woman that was a prostitute and defending her from the religious hordes that wanted to kill her according to the mossaic law. If not for the love and compassion of Christ there would be no faith or religious possibility for me.
"At least christians have enough sense to know that doling out such punishment isn't theirs to dole out and they refrain from doing so. Maybe the Muslims will learn that someday."
Amen to that :-) wise words my friend
Did you know your left shoelace is untied? :)
Really? Have you read Exodus Chapter 20? In the Forth Commandment God claims that he made the heavens and the earth and all that in them is. Was that statement deleted from the tablets of stone?
Webster's. The same definition science uses when ascertaining the presence of the same. Both design and intelligence, as commonly understood, are within the scope of scientific endeavor. Therefore science is free to hypothesize and test for it whenever, wherever, and however it pleases. Science is not subject to your narrow definitions or constraints.
A premise is evidence or reason.
A conclusion is the proposition inferred from the premise.
Now you answer a question. What's the difference between inductive and deductive reasoning?
For extra points: What is a hypothetical syllogism?
actually that is not the fourth commandment that is a declaration from God concerning the Sabbath which IS a commandment. I think you are confusing the two sorry but you are ;-)
But now that you remind me, I'm accusing you of twisting words around, distorting the truth, and giving solidity to pure wind.
What did highball distort? You said that ID isn't scientific. That's what we on the evolution side have been saying all along.
Thanks for the backup. I'm still trying to figure out what I did to deserve the personal attacks - he said ID wasn't scientific, and I agreed.
Go figure.
There is more than a shred of evidence for organized matter and, by extension, and intelligent designer.
You're making inferences again, not based on physical evidence but on emotions.
There is not one shred of actual physical evidence for a designer. Not one. The only evidence IDers can point to involves feelings or desires.
Even black holes, which we cannot see, have some physical evidence to support their existence. This "designer" does not.
LOL yes there where some huge erros and poorly made arguments that could not be ignored. i was sorry to have offended anyone but I could not stay silent.
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