The Transport Of Cargo By Several Molecular Motors

In human bodies, especially in cells, ATP and others like organelles are usually transported by several motors. And there are many results and existed theoretical models explaining the motion system. In this graduation thesis we mainly discussed the motion of the cargo transport by several motors. The model we use in the graduation thesis is an improved one of an existed model. In this model each motor is regarded as a bead-spring system. The improvement is making a idea of height. Then, we discuss the property of motion of the motor-cargo system, mainly about the velocity of the cargo and the stall-force of the system where the velocity of the cargo is zero. Firstly, we assume that motors could not bend to or drop from the system and the motors bend the cargo with spring. In order to get the final mean velocity, we must know the probability of each state where the system could be. We can assume the motors could only step forward and backward with fixed length L and the permutation of each state we used in the graduation thesis is the one similar to Dictionary ordering method. After that, we could use the probability, the change of the position of the cargo which is mainly determined by force balance condition to get the velocity. Secondly, assuming the motors could drop and bend to the system, we use the velocity got above to get the mean velocity. After that, we got the probability of molecular of different numbers. For the stall-force, we use the numerical method and discuss the difference. All the numerical examples in the paper are mainly for systems with three or four motors.