BIOL 1082 Lecture Notes - Lecture 15: Allantois, Organogenesis, Cleavage Furrow
Document Summary
Animal development 1 (reading: concepts: 47. 1-47. 2 in textbook: describe the events necessary for fertilization to occur, including the effects of sperm on eggs. List the different ways that polyspermy is blocked. Acrosomal reaction: as soon as a sperm head contacts the jelly coat of an egg, molecules in the jelly coat trigger the acrosomal reaction in the sperm. This reaction begins with the discharge of hydrolytic enzymes from the acrosome, a specialized vesicle at the tip of the sperm. These enzymes partially digest the jelly coat, enabling a sperm structure called the acrosomal process to elongate and penetrate the coat. Protein molecules on the tip of the extended acrosomal process bind to specific receptor proteins that jut out from the plasma membrane of the egg. The recognition event b/w the sperm and egg triggers fusion of their plasma membranes. The sperm nucleus then enters the egg cytoplasm as ion channels open in the egg"s plasma membrane.
