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)
Cute cartoon. You have a problem with Hovind's material and/or the way he presents it. Apart from Hovind are you aware that there are scientific questions about carbon 14 dating? I find it strange that you roll on the floor laughing at the fact that neither evolutionists nor creationists can prove the age of the earth.
Is it possible that you are reading only either Hovind's material or material that supports your point of view so that you are not aware of other problems around carbon 14 dating? Have you read the Gentry "halos" findings? Interesting scientific area of study that presents some problems for the evolutionary theory?
You should take my wife's advice...
"Don't laugh: you'll only encourage him!"
I'm on this reply and the count is 725 now???
What have I slept through??
(I geuss I'll see as I waste my life away reading these things. GRrrr....)
You snipped out the context of my post. The OP I was responding to created the sharp delineation. He was using a false premise, I simply pointed it out.
"Suppose we created artificial life in a computer. Our position would be in some sense "supernatural" with respect to the universe of that electronic life form, in much the same way that God is "supernatural" to us.
Good point. However if this life is unable to communicate directly with us and unable to run tests on our reality it would hardly consider us part of its 'natural' environment.
Our ability to test is limited to those events and objects that follow the laws of physics in a consistent way. If we lose that consistency because some cause is 'above' those laws we loose the ability to test.
In the case of our little computer friends, if we set up their environment with consistent rules and reactions and avoid interfering, they could fully investigate their environment without relying on our environment or our input. Our existence becomes unimportant to their investigation of their own environment. If we instead play with their tests by overcoming the 'laws' of their environment, they will be unable to differentiate between what is a consistent law and what is, in their view, supernatural. They will never be able to trust their tests.
If communication between our creations and ourselves is common place, then the situation would be different. In fact they would not need to investigate their environment because they could just ask us. We would no longer be supernatural, because their environment would be a subset of our environment.
The former case is the situation we find ourselves in, we do not know and can not communicate with anything in the environmental superset we are a subset of, if it indeed exists. What we do know is the consistency we experience in our efforts to examine our environment. It allows us to trust the outcome of our tests.
It is true that the sharp line between natural and supernatural we observe in our own lives may break down and be blurred in the quantum microcosm.
Funny thing is, the more physical phenomena we find we can test, the more inclusive and larger the natural environment becomes. However, the supernatural stays the supernatural, simply because it is definitional. What is included in the category may change, because of our abilities, but the categories will not change.
That's enough of my rambling. If I say too much more I may not be able to understand what I said. :)
I will add that this 'supernatural influence problem' really isn't all that is wrong with the current incarnation of ID, especially the version pushed by Behe and Dembski. That version has major problems with methodology and the prevalence of false positives and false negatives. Dembski's 'complexity' has major problems as well.
Kinda like: "Katrina is on her way. Be sure you are safe."?
You've pegged it correctly. THIS is the choice most Science puts us into as well.
When fishin', and they ain't bitin'; change yer bait.
"But because you are lukewarm...."
Go to Wally-World and pick up a pair of SpongeBob © underpants that state, boldly: "I've got gas!"
$7.92
No sir, that is not what is meant by supernatural in the case of God or in these discussions about science. What is meant by supernatural is a phenomena or cause that not only is exempt from the physical laws we utilize in testing science but can willfully change or circumvent those laws. This potential inconsistency in physical laws makes any result of tests we perform useless.
I'm sorry you find this difficult to understand.
John 14:12
12 I tell you the truth, anyone who has faith in me will do what I have been doing. He will do even greater things than these, because I am going to the Father.
Was Jesus nuts?
"Aye... there's the rub" isn't it?
Vast amounts of research and thought go into figuring THIS out!
(You are obviously not a KJV only type of guy ;^)
Do you deny that the long ages obtained through C14 dating are used to support the theory that earth is very old? I see your point, but you would agree that there is a correlation between the two issues wouldn't you?
OOoooh!
My doctor says I can tell folks I've been cured of this!
(Stitches come out in two days...)
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