Normally a cell has a mechanism that controls its division. As far as I know, it checks surface area and stuff like that to decide to go for mitosis or not.
However, this is not the case for a zygote. A zygote, after around ~14 days starts to divide rapidly and forms the blastula. What mechanism controlls this "rapid division"? Why can zygote divide rapidly when it has not reached a high surface area or doesn't have enough mitogens to induce the cell division? Does the zygotes mini-cells have a cell cycle like other cells but they are really fast? Or do they just copy the DNA and divide rightaway?
And when I first saw the video of this stage, I was surprised. The DNA is a one long molecule; how fast do those replicators work?