Question

Frog development. Explain the connection between the sperm’s introduction of the centriole and the formation of the “Organizer”. Include molecular details! Please explain in least 2 paragraphs

Answer 1

The entry point of the sperm into the egg is more like the dot that goes on to break the egg symmetry.After sperm entry into the egg and  by the time the two nuclei meet, the two sperm centrosomes undergo separation and they are start to form the division spindle for the first cleavage.The sperm donates a centrosome to the egg then triggers the cytoskeletal rearrangements.The sperm centrosome, a tiny organelle then functions to start the microtubule formation and this acts as an organizer of the spindle apparatus and this defines the axis of the first cleavage.Also, with the sperm entry,the rotation of the cortex of the cell relative to the inner cell massis triggered and this rotation moves the determinants present on the on the vegetal (yolky) side of the egg towards the animal/vegetal border of the egg.. A grey "cresent" appears to be formed  where the clear vegetal cortex lies over the grey animal inner cell mass.TThe grey crescent is the actual site of the formatuion of the future organizer that runs along the anterioposterior axis.