Microtubules originate on the centre of the cell taking the positive end to the periphery of the cell, while the negative end remains turned to the centre of the cell. The melanosomes move along these microtubules using motor proteins desiganted kinesins and dyneins. The kinesins are responsible for moving the melanosomes to the positive end of the microtubule (periphery of the cell) generating dark-colored cells, whereas dyneins move the melanosomes to the negative end of the microtubule (centre of the cell) generating light-colored cells.
They may depend on PH of the water, nutrients, and sunlight.
A prime mover is a muscle whose contraction is chiefly responsible for producing a particular movement. The muscles act on major joints within our bodies. Some more familiar ones are your biceps, triceps, and hamstrings.
