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'd call that an intellectual leap if I thought you were guilty of anything intellectual.
Desperate attack of trolls placemarker.
Golly -- does this mean you can only dish it out? And you do dish it out with great gusto. Read your own posts on this thread, and perhaps you'll understand my amusement at you, of all people, whining about "insulting" comments.
However, my comment was justified, and I have provided specific examples to justify my concerns about your veracity. I was merely telling you the truth. Sometimes that hurts.
I understood that. I was trying to stay within the context of your comment ... my apologies if I slipped beyond it.
Not enough time to fully digest your post -- looks like some interesting thoughts. I'll try to respond later.
Tell you what, "son." When you can discuss like an adult -- honestly, and without a pile of insults -- then we can try this again.
Your behavior doesn't help your cause at all. The choir might like it (or not); anybody else just sees you tossing spittle, and they aren't impressed by you, or by the things you're saying.
How so, and why? Please try to refrain from circular reasoning in your reply.
Has occured to you that, if indeed God created the heavens and the earth and all therein, that He used scientific principles to do so, and that therefore it may be unnatural to separate theology and science? That a compulsion to separate the two may redound to a scientifically innaccurate assessment of reality, which of itself is the proper object of science. If God is at all involved with the universe as we know it, then He is also a proper object of science, of knowledge, and all human reason is about.
Certainly there will remain matters beyond the reach of science. To state outright that God is one of them and leave it at that is to create a stultifying fence.
Is it "unscientific" to be emotionally involved in scientitifc pursuits? Are emotions entirely outside the realm of scientific inquiry? Absolutely not. Science in general accords with reailty, and if God created reality, it is a particulary bumbleheaded idea to insist that science and religion must always be compartmentalized separately from one another. To maintain such a view is to introduce a false dichotomy.
"Religion and science don't mix." Really? Who says so, and what scientific reasoning can be held forth in support of such a sweeping point of view that it colors the interpretation of evidence and throttles the bounds of science itself?
Too many scientists who believe God is ultimately and physically invloved with the physical world are mewling out of fear for a bunch of misguided ideologues. Shame on them. They have the last laugh. Science and God belong together like flesh and blood, mind and matter. The physical evidence points solidly in that direction. There is no harm in pursuing science with just this point of view.
It's time for certain ideologues to ride their little cartesian rocking horses out of the science classroom and into the sunset.
How does one quantify the Lord? One cannot. Science is about measuring the measurable, and quantifying the quantifiable.
It's time for certain ideologues to ride their little cartesian rocking horses out of the science classroom and into the sunset.
Shame on you and your snide attitude.
I didn't say otherwise. I was questioning what indirect evidence had to do with ID's testing problems.
You know, debating anything with you is like trying to tackle a kangaroo. It's impossible to predict where you'll hop to next.
Proof positive they are related to us,...their wives wouldn't let them go on a drunkards walk.
The universe is vast and complex. So it follows that its creator must be even more complex. To paraphrase your statement, it seems implausible that we should believe a creator exponentially more complex than a watch could could just be.
Don't you dare go on the 'proof' trip. Evidence! Its all about evidence.
As far as those skulls are concerned, lineage is not just based on simple morphology but on a number of other factors such as observing and comparing diagnostic features, comparing changes in teeth placement and type as well as tooth mineral content. There are quite a few more physical attributes that are examined, depending of course on the condition of the fossil and what predictions have been made on its taxonomy (if possible). The environment the fossils are found in, type and number of accompanying local organisms, type and quantity of plants, evidence of climate, virtually anything that can be determined about the organism's habits, food source or competitors from its surroundings factor into its placement.
"Since the ID/creationist argument to which you refer already invokes argument from incredulity, adding in another logical fallacy shouldn't be any problem at all."
And since at least one creationist here has said that logical fallacies are compatible with science, there should be no problem. :)
Please if you cannot understand my points, simply ask me to expand upon them don't just jump off into wild tangents because you think I said something I didn't.
Many theories in science have been proved.
_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_- _-_-_-_-_-_-_-_-
Suggesting that Ichneumon has never... blah, blah, blah,... shows that you are definitely not paying attention, or you are deliberately misrepresenting Ichneumon's posts.
Since I initiated contact with neither one of you to begin with and both of you could only respond to what I had originally said with fallacies in logic...
There is no point of your complaint, you have no basis using the formal rules of logic to attack me with.
This is why many times I will break ranks with the orthodox atheists... there is no such thing as an ecumenical atheist...
I see no logic in attacking the religionists, especially using an ‘appeal to false authority’ (an informal fallacy in logic often used against religionists like yourself and Ichneumon).
Indeed. Every child who ever asked, "Where did God come from," expressed an intuitive understanding of the paradox.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.