Mammalian Gamete

• Ovum


  Contains the zona pellucida which is a protective coating
• Fertilisation


  1. Sperm have to penetrate the zona pellucida

  2. Zona pellucida hardens after sperm have entered
• Zona pellucida


  Main purpose is to prevent polyspermy
• Ovum contains a haploid nucleus so that a full set of chromosomes is restored at fertilisation
• Cortical granules 


  Release substances which cause the zona pellucida to harden
• Follicle cells


  • Form a protective coating around the egg
• Spermatozoa


  • Contain many mitochondria to provide energy for rotation of the flagellum which enables the cell to move
• Acrosomes


  Contain digestive enzymes which break down the zona pellucida and allow sperm to penetrate the egg