I.
MICROTUBULES
-made up of tubulin monomers
-thickest & largest polymer
-shape cell & guide movement of organelles
-help separate chromosome copies in
dividing cells
-grow out of a centrosome:
region near
nucleus considered “microtubule-organizing
center”
a) CILIA/FLAGELLA
Specialized arrangement:
core of
microtubles sheathed in plasma membrane –
9 doublets of microtubles in a ring, in center
are 2 single microtubles “9+2” ONLY IN
EUKARYOTES!
Prokaryotes have helical
filaments that rotate like screws
Flagella: (long/big, 1or 2)
Motion – snake-like, undulates, forward
motion
Cilia:
(short, lots of them)
Motion – back and forth motion “oar-like”,
power strokes and return stroke, beat
together
II.
MICROFILAMENTS
-actin filaments
-finest
-involved in cell division/cell pinching
-in all eukaryotes
-twisted double chain of actin subunits
-forms structural networks:
links/branches
-structural role:
bear tension(pulling forces)
-contain protein:
Myosin, Actin
-myosin act as motor protein by
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- Spring '08
- Bever
- motor protein, actin filaments CONTRACTION
-
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