Cleavage abruptly slows. MBT is at the 12th cleavage in the frog . If inhibited after fertilization by drugs that stop transcription, mammal eggs arrest at the two-cell stage. Translation of zygotic mRNA begins at the two-cell stage in the mouse and at the four cell stage in the human. MBT in Drosophila is is at the cellular blastoderm stage.
Humans have a blastocyst.
This applies to many, but not all, eggs. The human embryo has no yolk and cleavage is holoblastic. There is an increase in cell membrane at cytokinesis resulting from stretching and synthesis. This site maintained by the Life Sciences Web Team .