What activity during oocyte activation prevents penetration by ...

[gonzo233]

What activity during oocyte activation prevents penetration by additional sperm?

Question 2

A gene's position on a chromosome is called a
 A) karyotype.
  B) map.
  C) recombinant.
  D) genome.
  E) locus.

[Yixagurpuldink]

Answer to Question 1

The first sperm to penetrate the oocyte triggers a sequence of changes that block entry by other sperm, or polyspermia. Polyspermy is prevented by depolarization of the egg membrane by opening of sodium channels and by the cortical reaction triggered by the release of calcium ion from smooth ER within the oocyte. The calcium ion stimulates the vesicles to undergo exocytosis. Their contents cause the zona pellucida to harden, creating a barrier against further sperm penetration.

Answer to Question 2

E

[gonzo233]

Gracias!

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