Answer to Question #126834 in Biology for Larry Charleston

Question

3) Calcium ions are not present when an egg comes into contact with multiple sperm cells. What is likely to happen in this scenario? Please include both the results for the process of fertilization itself, and the end result that would be expected for the embryo (

Answer 1

When an egg comes into contact with the single sperm cells, the concentration of calcium in the cytoplasm increases. Calcium induces the release of cortical granules and blocks polyspermy, reactivates cell cycle, and stimulates the pronucleus formation. As a result, the absence of calcium will lead to polyspermy (the fertilized egg will contain a higher number of chromosomes). On the other hand, the lack of calcium will block the progression of the cell cycle and egg cells will not proliferate while the embryo will not be formed.