Question

The second maturation division of the mammalian ovum occurs

• A. Shortly after ovulation before the ovum makes entry into the fallopian tube
• B. After the ovum has been penetrated by a sperm
• C. Until the nucleus of the sperm has fused with that of the ovum
• D. In the Graafian follicle following the first maturation division

Answer 1

The correct option is B After the ovum has been penetrated by a sperm

In mammalian ovum, during maturation phase, meiosis occurs. Nucleus shifts towards animal pole and undergoes meiosis-I. After fertilization the second meiotic division is completed with unequal cytoplasmic cleavage. This forms a large cell called the ootid, with essentially whole of the cytoplasm and a very small cell, the second polar body.