WHAT HELPS THE SPERM LOCATE THE EGG

Scientists from MBL (Marine Biological Laboratory) have discovered a vital molecule that drives a chemical attraction between egg cells and sperm cells of marine invertebrates. Over a century ago, it was discovered that marine invertebrate eggs release a type of chemical that attracts sperm. This process is known as chemotaxis.

Once the sperm senses the chemical, it swims up toward the egg, with the help of an increase in the concentration of Calcium ion.

The Calcium ion concentration is in the sperm cell’s tail, which propels the sperm as it swims.
The molecule that helps the sperm’s tail become more alkaline is the one that’s elusive. If the sperm becomes alkaline, and the Calcium ion concentration increases, the sperm could reach the beckoning egg.

The said molecule shares characteristics with pacemaker channels, which control the brain’s electrical activity and heartbeat. The voltage sensor activates the exchange of protons and sodium in the sperm. When this is disabled, the sperm cannot reach the egg anymore because it is lost.

[Link: https://www.sciencedaily.com/releases/2018/08/180804100128.htm]