THREE TYPES OF FIBERS - I MICROTUBULES-made up of tubulin...

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