BIOL 001 Lecture Notes - Lecture 30: Zp3, Acrosome, Cortical Reaction
6 Aug 2020
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Development: all changes that occur during your entire life cycle. Species chosen for research easily studied. Example: development events of frog (fig 47. 2) Sperm (usually flagellated, motile) + ovum (large, non motile) Aid in fertilization (attract sperm that can detect a specific chemical signal, unique to each species) Provide a physical barrier to interspecific fertilization especially important for external fertilization (ie gametic isolation) Sperm bind to surface receptors ensures that the two cells are of the same species (lock and key model) Results in changes to the surface of the egg prevent polyspermy (we don"t want this) Most research done on echinodermata (sea urchins) Jelly coat releases chemicals > attract sperm (chemotaxis) Only 1 sperm nucleus enters the egg. More than 1 sperm enters > usually fatal. Unfertilized egg polarized (concentration of ion is different from inside to outside) Ion channels open seconds after fusion > allows na+ to enter egg. Ca2+ released of the endoplasmic reticulum into the cytoplasm.
