01:119:116 Lecture Notes - Lecture 16: Acrosome Reaction, Lipid Bilayer Fusion, Polyspermy
25 Jul 2017
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Fertilization: seq fertilization, c/c fertilization in different animals. Cleavage: seq, iov cleavage, c/c cleavage patterns. All changes that occur during entire life cycle. Species chosen for research easily studied. Sperm (usually flagellated and motile) + ovum (large and nonmotile) zygote. Egg is one of the largest cell in human body, sperm are one of the smallest cells. N + n 2n: fertilization restores diploidy of cell. Activates egg (triggers biochemical reactions) and stimulates reactions promoting development. Usually based on the chromosomes within the cells. Barrier to interspecific fertilization especially for external fertilization. Bind to surface receptors ensure same species. Don"t want fusion of gametes from different species. Change to egg surface prevent polyspermy (2+ sperm fertilizing the same egg) Polyspermy is very bad results in 3n cell. Analyzing gg coverings from internal to external. 2nd layer = vitelline layer (fig 47. 3) 3rd layer = embedded in vitelline layer and pm are sperm-binding receptors.
