Sperm enzyme dissolves eggUploader: Kylen 6 days ago Subscribe 961
Animal Fertilization and Cleavage. The most common way is to prevent the entry of more than one sperm into the egg. On the left is a sea urchin blastula, and on the right is a frog blastula. Mucopolysaccharides released by the cortical granules produce an osmotic gradient that causes water to rush into the space between the plasma membrane and the vitelline envelope, causing the envelope to expand and become the fertilization envelope Figures 7. Positional information is already contained within many eggs, with the exception of mammals. The molecular mechanisms are less well understood than those of sea urchins. Changes in cell behavior and cell cleavage patterns during early embrogenesis results in a cell blastocyst consisting of the inner cell masswhich will form the embryo, and the trophoblastwhich will form extraembryonic tissues.