Q. What is the first polar body? How different is it from the oocyte II?
In oogenesis the oogonium differentiates into oocyte I (2n) and this cell enters meiosis and after finishing the first meiotic division (meiosis I) the oocyte I forms two cells: the first polar body and the oocyte II (n). The oocyte II is bigger because it gets almost all the cytoplasmic and the cytoplasm structures of the oocyte I as a strategy for metabolite and nutrient storage. The oocyte II cell goes then to the second meiotic division the first polar body is very small and almost lacks cytoplasm it stays or disintegrates attached to the oocyte II.