NEET2010ZoologyHuman ReproductionActual
The second maturation division of the mammalian ovum occurs
Options
- Ashortly after ovulation before the ovum makes entry into the Fallopian tube
- Buntil after the ovum has been penetrated by a sperm
- Cuntil the nucleus of the sperm has fused with that of the ovum
- Din the Graafian follicle following the first maturation division
Correct answer
B. until after the ovum has been penetrated by a sperm
Step-by-step solution
In mammalian ovum during maturation phase, meiosis occurs, nucleus shifts towards animal pole and undergoes meiosis-I. After fertilization (penetration of sperm), the second meiotic division is completed with unequal cytoplasmic cleavage. This forms a large cell the ootid with essentially whole of the cytoplasm and a very small cell, the second polar body.