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Protein interaction between gametes(male & female

  • Male gamete is called SPERM &Female gamete is called OVUM.
  • Fertilization ,process male & female gamete fuse together to form Zygote(2n).
  • Sperm head contain special vesicle called Acrosomal vesicle or acrosome.
  • Acrosome is derived from Golgi bodies & acrosome contain hydrolytic enzyme(protein) ,help in dissolve the egg shell.
  • Ovum contain large amount of yolk ( comprises lipid,protein & polysaccharides) called megalecithel eg.birds,reptiles ,small amount of yolk, microlecithel egg -sea urchin ,mammals.Outer layer of ovum of lower organism called vitelline layer and higher organism (mammals) called Zona pellucida.
  • Zona pellucida is made up of three glycoprotein viz .ZP1 ,ZP2 & ZP3 (Z for zona & P for protein) and three glycoprotein are arranged as layer called outer ZP3 ,middle ZP2 & inner ZP1 and the 1st of all sperm head bind to outer ZP3 glycoprotein .
  • Protein interaction are possible when protein product(ligand & receptor) are express on the surface of sperm and ovum membrane.
  • Sperm membrane has immunoglobulin super family protein called IZUMO (discovered by Japanese researcher ) act  as ligand & their receptor are present on ovum membrane called JUNO.
  • When interaction occur then cortical granule release their content via exocytosis  .The content is enzyme called N-acetylglucosaminase that cleave the binding b/w sperm and N-acetylglucosamine of ZP3 then pro nucleus of gamete is fuse ,fertilization occur and Zygote is formed,
  • Zygote does not have Growth phase why? because all the content(protein ,enzyme which is require for division ) are already synthesized in diplotene phase .

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