Question

Fertilization is fusion of
a. Diploid spermatozoan with the diploid ovum to produce a diploid zygote
b. Haploid spermatozoa with the diploid ovum to form a diploid zygote
c. Diploid spermatozoan with the haploid ovum to form a diploid zygote
d. Haploid spermatozoa with the haploid ovum to form a diploid zygote

Answer 1

Hint: Fertilization is the fusion of spermatozoan with the ovum to form a diploid zygote. It is a physicochemical process involving male and female gametes which leads to the formation of the zygote, which later by the process of mitotic divisions form an embryo.

Complete answer:
Syngamy: this is also called fertilization in which two haploid gametes fuse to form a diploid zygote. The male gamete is small and motile called sperm and the female gamete is large and non-motile called an ovum. The sperm enters and swims to fertilize the ovum of its species by the process of capacitation, it occurs in the female reproductive tract.

The process of fertilization is carried out in three steps:
> Penetration of sperm: The sperm comes in contact with an ovum, it releases sperm lysin which dissolves the zona pellucida layer of the ovum, and finally, it penetrates the ovum leaving behind its tail part.

> Activation of ovum: this includes a series of events constituting the activation of ovum which is initiated by sperm penetration.

> The fusion of gametes: This is also called amphimixis. The nuclear membrane of both sperm and egg nucleus breaks followed by the fusion of both pronuclei. This results in the formation of zygote. The zygote further undergoes a series of mitotic divisions to form an embryo. The zygote further undergoes a series of mitotic divisions to form an embryo. The zygote further undergoes a series of mitotic divisions to form an embryo.

Hence, the correct answer is option (D).

Note: The sperms are formed by spermatogenesis. In this, through division haploid spermatid is formed which by spermatogenesis forms a motile sperm. The ovum is formed by oogenesis. In this, primordial germ cells through divisions form a haploid ovum. The haploid spermatozoa and haploid ovum fertilized to form a diploid zygote.