Question

Egg apparatus consists of

• A. Oosphere + Central Cell
• B. Oosphere + Antipodal Cells
• C. Oosphere + One Synergid
• D. Oosphere + Two Synergids

Answer 1

The Correct Option is D

An egg apparatus is a group of three cells located in the embryo sac near to the micropyle. It consists of one egg cell and two associated cells known as synergids. In flowering plants, the functional megaspore undergoes mitotic divisions three times. During the first mitotic division, it gives rise to the embryo-sac. The two nuclei present in the sac divides to form four nucleate and then eight nucleate structures. One nucleus from each side shifts to the middle and are called polar nuclei. The three nuclei present at the micropylar end forms an egg apparatus and the remaining three cells at the chalazal end are called as antipodal cells. 

The other two options antipodal cells and central cell are incorrect as they are not a part of egg apparatus.

• Antipodal Cells: These are the three haploid cells situated at the chalazal end of a mature embryo sac. 
• Central Cell: The central cell is a binucleate cell that fuses with a sperm cell to form a triploid endosperm. 

Since an egg apparatus contains three cells - an egg cell (oosphere) and two synergids, not just one, hence option C is also incorrect.