Compare F-Actin with G-Actin

Compare F-actin with G-actin.

A) F actin is a twisted strand made up of two rows of G actin subunits where myosin heads can bind.
B) G actin is a twisted strand made up of two rows of F actin subunits where myosin heads can bind.
C) F actin binds myosin during muscle relaxation and G actin binds myosin during muscle contraction.
D) F actin binds myosin during muscle contraction and G actin binds myosin during muscle relaxation.
E) F actin is functional actin that contains myosin binding sites and G actin covers the binding sites on F actin to prevent actin-myosin interaction.