 However, prokaryotic flagella are entirely different in structure from eukaryotic flagella and do not contain microtubule-based structures.The cytoskeleton formed by microtubules is essential to the morphogenetic process of an organism's development.For example, a network of polarized microtubules is required within the oocyte of "Drosophila melanogaster" during its embryogenesis in order to establish the axis of the egg.