Unformatted text preview: ove, alm os t down to the atom . The dynein m otor, on
the other hand, is s till poorly unders tood. Myos in m olecules , bes t known for their role in m us cle contraction,
form chains that lie between filam ents of another protein called actin. Each m yos in m olecule has a tiny head
that pokes out from the chain like oars from a canoe. Jus t as rowers propel their boat by s troking their oars
through the water, the m yos in m olecules s tick their heads into the actin and hois t them s elves forward along the
filam ent. While m yos in m oves along in s hort s trokes , its cous in Kines in walks s teadily along a different type of
filam ent called a m icrotubule. Ins tead of us ing a projecting head as a lever, kines in walks on two â€˜legs â€™.
Bas ed on thes e differences , res earchers us ed to think that m yos in and kines in were virtually unrelated. But
newly dis covered s im ilarities in the m otors â€™ ATP-proces s ing m achinery now s ugges t that they s hare a
com m on ances tor-m olecule. At this point, s cientis ts can only s peculate as to what type of prim itive cell-like
s tructure this ances tor occupied as it l...
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This document was uploaded on 03/23/2014.
- Summer '14