22 Dec 2011

Molecular motors - a lesson in nanotechnology from Nature

Roop Mallik

They are small, and there are billions of them inside you. Tiny machines, a thousandth of the thickness of human hair, but robust and designed for an amazing variety of functions. Science fiction? Think again … this is real, as real as flesh and blood !! If you can get your hands on a high school biology text book, flip through to the mandatory schematic of an animal cell. Look closely, what you will see is not a floppy bag with random things thrown in here and there. There is amazing structural organization within the cell, with several compartments (e.G. The nucleus, Golgi bodies, mitochondria) at specific locations. Many of these compartments are specialized “factories”, each with its own assembly line which requires specific raw material as input and generates specific products. A constant give-and-take of materials occurs within these factories, because each is dependent on the other. In the big picture of things this incessant exchange of material keeps the factories of the cell functioning, which in turn is what keeps us alive.

How do things get moved inside the cell?
Simplified schematic of the transport network of a typical cell. Molecular motors are shown ferrying different cargo. The Kinesin motors usually move towards the cell periphery, while Dyneins move towards the cell center. More detailed schematics of the motors shows the “legs” on which these motors walk while carrying cargo. For an idea of the size scales involved, kinesin and dynein motors have dimensions of approximately 50 nanometers. A nanometer is one-billionth of a meter (10-9 meters). These motors exert forces of pico-Newtons. A pico-Newton is one-thousand-billionth of a Newton (10-12 Newtons). We usually measure forces in Newtons in day-to-day life. “
See more:-Roop Mallik Lab

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