Bacterial flagellum

I think you're mistaken about that. The flagellum doesn't spin like the rotor of a motor. It whips about (hence the name "flagellum", from the latin for "whip") but doesn't actually rotate. It's more like a wisking action.It's not really like an electric motor. It's more like a whipping hair than anything else, as far as I know.

You believe wrong, according to my wife's cell-molec textbook (World of the Cell 4th Edition, Becker, Kliensmith, and Hardin). Bacterial flagella beat back and forth. They don't rotate in place like the shaft of an electric motor.Nothing in nature rotates freely, not even flagella.

I'm looking right at it; it has pictures and stuff, and it's pretty clear.Maybe we're miscommunicating or something. It seems to me that the Rat is saying that the bacterial flagellum free rotates within its socket, like the shaft of a motor, around the long axis of the flagellum.The textbook says that it beats back and forth, or whips around in a circular motion, but doesn't actually spin. The flagellum whips around like if you were to grab a garden hose in one hand and move your hand up and down and left and right, in a circle - the hose whips around, kind of in a helix, but doesn't actually spin freely of your hand.Like I said, the textbook is pretty clear about that. I don't think I'm misunderstanding it. From what I'm reading, bacterial flagella don't rotate in a socket like the shaft of a motor, they whip around like whips.

So, what exactly propels it? What's the mechanism? Oh, wait, never mind, I read further in the thread.Moreover, why doesn't it just spin the bacterium? Or does it, and that's why it's not all that efficient?This message has been edited by crashfrog, 05-20-2004 01:52 PM

Wild stuff. Well, never let it be said I won't admit it when I'm wrong - I was wrong about the bacterial flagellum. Clearly I misunderstood The World of the Cell; probably it was only referring to the eukaryotic flagellum.Neat stuff, though. I don't even begin to understand it, though.

It's not too hard to concieve of a metabolic pathway in a bacterium that would supply more or less energy to the flagellum based on the intensity of light at another part of the bacterium. Light can catalyze chemical reactions.