egg cell

• • The egg cell is also called an ovum.
  • It is one of the largest cells in the body, approximately 0.12mm in diameter.
  • The cytoplasm has a large volume containing lots of nutrients and lots of organelles, including 1000s of mitochondria to supply large quantities of ATP (energy) for processes needed during growth such as cell division, protein synthesis and DNA replication.
• • The cell membrane of the cell is surrounded by the thick transparent protective layer called the zona pellucida.
  • On the outside of the zona pellucida of the egg cell is a layer of smaller cells (that originated from the ovary from which the egg was released at ovulation) called the corona radiata.
  • The corona radiata layer supplies proteins to the fertilised egg for its development
  • A fertilised egg cell will divide by mitosis to become the embryo