fertilization, union of a sperm nucleus, of paternal origin, with an egg nucleus, of maternal origin, to form the primary nucleus of an embryo. In all organisms the essence of fertilizati… See more

Maturation is the final step in the production of functional eggs (oogenesis) that can associate with a spermatozoon and develop a reaction that prevents the entry of more tha… See more

Certain components of an egg’s surface, especially the cortical granules, are associated with a mature condition. Cortical granules of sea urchin eggs, aligned beneath th… See more

The surfaces of most animal eggs are surrounded by envelopes, which may be soft gelatinous coats (as in echinoderms and some amphibians) or thick membranes (as in fishe… See more