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HalfMooner
Dingaling
Philippines
15831 Posts |
 Posted - 02/04/2008 : 04:32:26
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PZ Myers has posted a criticism of Harvard's beautiful, now (largely due to the Discovery Institute's plagiarism) famous, but flawed animation, "The Inner Life of a Cell."
Left foot forward, march! Kinesin, as shown in Harvard's "Inner Life of a Cell"
Myers has a problem with the precision of molecular interactions shown in the video. Through examples, PZ brilliantly demonstrates that things on such a nano scale simply don't behave so neatly.
They way they are portrayed in the Harvard video is so precise that it unintentionally but effectively invites Creationists like the Disco Institute's chuckleheaded liar Michael Behe to compare the molecules to precisely operating and "designed" machines: | They're little trucks and busses that run around the cell that take supplies from one end of the cell to the other. They're little traffic signals to regulate the flow. They're sign posts to tell them when they get to the right destination. They're little outboard motors that allow some cells to swim. If you look at the parts of these, they're remarkably like the machineries that we use in our everyday world. |
PZ points out that the oversimplification in the video is a problem, and that realistically, the molecules behave more like "a mosh pit filled with meth addicts." He says, in part:| Take for instance the behavior of kinesin, that stalk-like molecule seen marching in a stately way down a tubule, with two "feet" in alternating step, towing a large vesicle. That's not how it moves! We have experiments in which kinesin is tagged — it's towing a fluorescent sphere — and far from a steady march, what it does is take one step forward, two steps forward, one step back, two steps forward, one back, one forward … it jitters. On average it progresses in one direction, but moment by moment it's a shivery little dance. Similarly, the movie shows the monomers of tubulin zooming in to assemble a microtubule. No! What it should show is a wobbly cloud of monomers bouncing about, and when one bumps into an appropriate place in the polymer, then it locks down. |
Good reading, this post. PZ's not just a tough, in-the-trenches scientist, he also knows how to turn a phrase.
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“Biology is just physics that has begun to smell bad.” —HalfMooner
Here's a link to Moonscape News, and one to its Archive. |
Edited by - HalfMooner on 02/04/2008 04:43:47
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"A mosh pit filled with meth addicts"
