5 - F 5.12 . Fertilization: F y 0 ) - the fusion of egg and...

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Fertilization: F --- the fusion of egg and sperm 0 ) X F X
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Fig.11.10 Acrosome: F Acrosomal vesicle: F Acrosomal reaction: F Capacitaion: F in female reproductive tract; 1951; MC Chang 0 )
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Sperm pronucleus Egg pronucleus External F frogs F fish Internal F fly F mammals F birds F Polyspermy (
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Fig.11.11 Fertilization of a mammalian egg Cumulus cell layer: X Cortical granules: F Zona pellucida F 1. Hyaluronidase X ( F X ) 2. SED1, which binds to the zona pellucida, ZP3(receptor) ( X ( ) 3. Acrosomal reaction: b-N- acetylglucosaminidase, acrosin (protease) 4. Binding to egg membrane: fertilin---CD9 (receptor in egg)
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Fig.11.12 Deploarization of the sea urchin egg plasma membrane at fertilization (when sperm-egg fusion) Changes in the egg membrane at fertilization block polyspermy In mouse fertilization, there is no change in membrane potential.
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Fig.11.13 The cortical reaction at fertilization in the sea urchin. Exocytosis: F Vitelline membrane: Hyaline layer: F Micovillus: F Fertilization membrane: F A wave of calcium release after sperm entering egg.
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Fig.11.14 A Calcium wave initiated at fertilization results in egg activation. A wave of calcium release after sperm entering egg. Fertilization and egg activation in mammals and sea urchins are associated with an explosive release of free Ca2+ ions within the egg, producing a wave of calcium that travels across it.
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The sharp increase in free Ca2+ is crucial for egg activation. F Artificial activation of egg: animal cloning; F Xenopus eggs activated by prodding with a glass needle. r Xian)
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Fig. 11.15 Profile of maturation-promoting factor (MPF) activity in early Xenopus development Mitosis: F Meiosis: F Zygote: F Calcium initiates development of the fertilized egg by its action on proteins that control the cell cycle Ca2+ Calmodulin-dependent protein kinase II Degradation of cyclin component of MPF Meiosis
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(abbreviated MPF , also called mitosis- promoting factor or M-Phase promoting factor ) is a heterodimeric protein composed of cyclin B and cyclin-dependent kinase ( CDK1 , also known as Cdc2) that stimulates the mitotic and meiotic cell cycles . MPF promotes the entrance into mitosis from the G2 phase by phosphorylating multiple proteins needed during mitosis. MPF is activated at the end of G2 by a phosphatase , which removes an inhibitory phosphate group added earlier. Cdk-cyclin complexes control the mitotic
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This note was uploaded on 09/03/2009 for the course BIO 503 taught by Professor Z.zyang during the Fall '09 term at Nanjing University.

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5 - F 5.12 . Fertilization: F y 0 ) - the fusion of egg and...

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