chp 13 and some 16

Sperm and Egg Cells

• Release of Sperm Cells

  • Many sperm cells are released during ejaculation.

  • The specific sperm that successfully reaches and fertilizes the egg cell is random.

• Ovulation

  • In females, during ovulation, a specific egg cell is released from the ovary.

  • Similar to sperm, the egg cell that is released is random among available eggs.

Meiosis in Gametes

• Arrested Meiosis

  • Meiosis in oocytes (egg cells) is paused for extended periods, sometimes for decades.

  • This prolonged arrest can happen at various stages of meiosis, particularly during prophase I until ovulation occurs.

• Spindle Attachment Checkpoint

  • Even if spindle fibers attach to chromosomes, cells may remain arrested before proceeding to meiosis II.

  • Cells can exist in this arrested state for many years before continuing the meiotic process, highlighting the complexity of gamete development.