Question

Second maturation division of mammalian ovum occurs:

• A. Until after sperm has penetrated ovum
• B. Until nuclei of sperm and ovum fuse
• C. In Graafian follicle soon after first maturation division
• D. Shortly after ovulation before entry into fallopian tube

Answer 1

The correct option is A Until after sperm has penetrated ovum

During oogenesis, primary oocyte grows and completes meiosis I (first maturation division) producing a large secondary oocyte and a small polar body. The secondary oocyte proceeds with meiosis II (second maturation division) but the division gets arrested at metaphase stage. In this stage of oocyte, the ovum is shed during ovulation. It passes into oviduct, where the cell cycle resumes only after the entry of sperm. So, the correct answer is option a.