Actin and myoglobulin are the compositions building muscles' stretching function. Microtubulin is the basic substance which provides the flagellum and cilium the function of movement.

肌动蛋白及肌球蛋白乃是构成肌肉伸缩机构的组成部分，微管蛋白是赋予鞭毛及纤毛能动的基本物质。