The Cooperative Behaviors Of Molecular Motors During Muscle Contraction

This dissertation is mainly concerned with the cooperative behaviors of molecular motors in muscle contraction.Molecular motors are protein molecules in cells that can convert chemical energy into mechanical energy. The dynamic behavior of single motor and the cooperative behaviors of large number motors become an interesting topic in biophysics now.In this dissertation,two particular cooperative behaviors of the molecular motors in muscle isotonic contraction are introduced: (l)no attached cross-bridges work at the same tempo, the working process is not affected by the environment; (2)no attached cross-bridges work at the same tempo, and the working rate is proportional to the very velocity of thin filament in the contraction. The relationship between velocity and extern load for the two cooperative behaviors are calculated based on the energy conservation.In this dissertation, the muscle cell is also investigated from the point of view of complexity. We propose a springs coupled little balls model. We compare two ways of activating little balls in which we find the random activating system runs more quickly than the assembled activating system.The whole dissertation is arranged as following:is an introduction for the relationship between physics and biology.Chapter is some biological knowledge about the muscle. Because we are particularly interested in skeletal muscle, we pay much attention to the skeletal muscle.In chapter t, the cooperative behavior of molecular motors in investigated. Two particular cooperative behaviors(mentioned above) are introduced.In chapter three we try to investigate the muscle cell from the point view of complexity system. We propose a springs coupled little balls model. We compare two ways of activating little balls in which we find the random activating system runs more quickly than the assembled activating system.Chapter-fou-ris a conclusion of the whole dissertation.