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Unformatted text preview: Discussion question set 8 I. The Cytoskeleton: Microfilaments 1) What are the differences between microtubules and microfilaments? • Microfilaments are smaller(8nm) whereas microtubules are larger in diameter (24nm) • Micofilament subunit is actin, microtubule subunit is tubulin • Microfilaments utilizes ATP during polymerization while microtubules utilize GTP • Actin filaments do not show dynamic stability they treadmill • Microfilaments have two protofilaments G actin and F actin • Rate limiting step in actin polymerization is nucleation (3 subunits) • 5x more proteins used in actin • Arp 2/3 can bind to preexisting filament, whereas gamma trp cant 2) This graph shows that the polymerization of microfilaments is dependent on the concentration of G-Actin. Lines A, B, and C represents 3 different polymerization rates. The black dots D, E, and F represent the critical concentration [Cc] on lines B, A, and C,...
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- Spring '08
- actin polymerization, FILA