Question

Q. Extrusion of second polar body from egg nucleus occurs:
A before entry of sperm into ovum
B simultaneously with first cleavage
C after entry of sperm but before fertilization
D after fertilization

Answer 1

Solution:
Extrusion of second polar body from egg nucleus occurs after entry of aperm but before fertilization.
The entry of aperm into the ovum induces completion of the meiotic division of the secondary oocyte.
Entry of sperm causes breakdown of metaphase promoting factor (MPF) and turns on anaphase promoting complex (APC).