In the presence of testosterone, the M llerian ducts develop while the Wolffian ducts degenerate. In Drosophila sex determination is controlled by the environmental temperature. Collagen a. Collagen self-assembles from tubulin dimers. The procollagen peptides are synthesized within the cytoplasm. Three procollagen peptides form a triple helix.
Collagen fibers have important functions in the mitotic spindle.
Spermatogonia may be connected with each other by cytoplasmic bridges. The axoneme arises from a basal body. The acrosome arises from fused mitochondria. Most of the spermatid cytoplasm is eventually sloughed off. Some differentiated plant cells were shown to be totipotent.