01:119:116 Study Guide - Zona Pellucida, Acrosome Reaction, Cortical Reaction
30 Oct 2014
School
Department
Course
Professor
Document Summary
Will reference to echinoderms, frogs, chickens, and humans; each of these animals has different life histories and strategies and most importantly the amount of yolk varies to each animal. Yolk is the stored energy in the egg which serves as food for the developing embryo. Echinoderm eggs have very little yolk because it is only needed until the egg becomes a tiny larva which obtains its own food. Human (mammalian) eggs have little yolk also because most of the nutrients for the embryo are obtained from the mother. Reptile and bird eggs contain a lot of yolk to suffice the embryo until it hatches. Acrosome is the tip of the sperm which contains hydrolytic enzymes. The commonly known egg is technically called a secondary oocyte until it is fertilized. Non-cellular zona pellucida covers the secondary oocyte and granulosa cells from the follicle surround the secondary oocyte and the zona pellucida. Once fertilized, the granulosa cells become the cellular corona radiata.
