Successful fertilization is most likely to occur when the oocyte is in:
Ans. A. The oviduct and has entered the second meiotic divisionFertilization occurs in the oviduct. The oocyte must have entered a second meiotic division to reduce the chromosome number of the oocyte to a haploid state (n) so that it may fuse with the sperm (also haploid), producing a 2n zygote. Fertilization does not occur in the uterus, especially not after the first meiotic division when the chromosome number is 2n. In the adult ovary, oocytes do not undergo mitosis. Graafian follicles do not enter the oviduct and are not fertilized. Fertilization does not occur in the uterus, and the oocyte does not implant. The blastocyst will implant in the uterus. In addition, extrusion of the polar body is associated with fertilization, but this event occurs within the oviduct.
The oviduct and has entered the second meiotic division
The uterus and has completed the first meiotic division
Metaphase of mitosis
The graafian follicle, which then enters the oviduct
Sex Hormones