Question

Select all that apply.

Once an egg has been fertilized, _____.

a a zygote is formed
b a barrier to other sperm forms immediately
c new genes are formed
d cytoplasm is always exchanged
e the zygote becomes haploid

Answer 1

The answers would be (a.) a zygote is formed, (b.) a barrier to other sperm forms immediately and (c.) new genes are formed. The process of fertilization begins with the fusion of the ovum with a sperm that will lead into the formation of the zygote and will eventually result into the development of a embryo.

Answer 2

The correct answers would be:

• a a zygote is formed
• b a barrier to other sperm forms immediately

Acrosomal and cortical reactions take place at the time of fertilization of egg and sperm.

Acrosomal reaction helps in penetrating the zona pellucida so that sperm nuclei can enter the oocyte.

Cortical reaction results in the hardening the zona pellucida which prevents the entry of any other sperm cell.

Post-fertilization, the oocyte completes its second meiotic division and matures into the ovum.

The pronucleus of the male moves towards the center of the oocyte in order to fuse with the pronucleus of the female. It results in the formation of a diploid zygote nucleus. It divides with the help of mitotic divisions and develops into the embryo.