Fis gure 11.2 Assembly and structure of actin fila ments (A)Actin monomers(G actin) polymerize to form actin filaments (F actin). The first slep is the formation of dimers and trimers, which then grow by the addition of monomers to both ends.(B)Structure of an actin monomer(C")Space-filling model of F actin. Nine actin monomers an rpr nted in different colors. (O Dan Richardson