Question

What happens during fertilization in humans after many sperms reach close to the ovum?
A. Secretions of acrosome help one sperm enter the cytoplasm of the ovum through zona pellucida
B. All sperms except the one nearest to the ovum lose their tails
C. Only two sperms nearest the ovum penetrate zona pellucida
D. All of the above

Answer 1

The structure of the ovum is a bit complex as compared to that of sperm and it is large. The process of fusion of a sperm cell with an associated egg cell is termed fertilization. The ovum is stationary while the sperm is motile.

Complete step by step answer: Humans internally fertilize through the process of copulation. Once a male has ejaculated, several sperms move to the higher duct (upper vagina) through the cervix and across the uterus fulfill the gamete within the Fallopian tube. Around solely 15% of the sperms can reach the fallopian tube.

Sperms undergo a process of the acrosomal reaction in which when they come in contact with the surface of the egg covering, the outgrowth releases its contained hydrolytic enzymes, additionally known as sperm cell lysins. Here because the spermatozoa approach the zona pellucida of the egg, the membrane encompassing the acrosome fuses with the cell membrane of the gametocyte (oocyte) thereby exposing the contents of the acrosome. During fertilization, a gamete comes in contact with the zona layer of the ovum or the egg cell and induces changes within the membrane that block the entry of further sperms. Thus only one sperm enters to fertilize the ovum. Contents embrace surface antigens, varied enzymes (like hyaluronidase) that are accountable for breaking the egg coating, to help the sperm enter the cytoplasm of the ovum and permitting the fertilization to occur.
Hence, the correct answer is Option A
Note: Before fertilization in humans to occur, certain conditions got to exist, to support the process. In females and males, the process of gametes formation is the process called gametogenesis. The gametes are typically haploid cells. The combination of genes is important to help humans to adapt to the changes in their atmosphere. The constant shuffling of the human genes will increase the standard variations within the offsprings of humans. The mix of completely different chromosomes from different oldsters is additionally necessary to permit the offspring to receive variations.